Pileus Git - ~andy/linux/blob - Documentation/DocBook/media/v4l/controls.xml

   1   <section id="control">
   2     <title>User Controls</title>
   3
   4     <para>Devices typically have a number of user-settable controls
   5 such as brightness, saturation and so on, which would be presented to
   6 the user on a graphical user interface. But, different devices
   7 will have different controls available, and furthermore, the range of
   8 possible values, and the default value will vary from device to
   9 device. The control ioctls provide the information and a mechanism to
  10 create a nice user interface for these controls that will work
  11 correctly with any device.</para>
  12
  13     <para>All controls are accessed using an ID value. V4L2 defines
  14 several IDs for specific purposes. Drivers can also implement their
  15 own custom controls using <constant>V4L2_CID_PRIVATE_BASE</constant>
  16 and higher values. The pre-defined control IDs have the prefix
  17 <constant>V4L2_CID_</constant>, and are listed in <xref
  18 linkend="control-id" />. The ID is used when querying the attributes of
  19 a control, and when getting or setting the current value.</para>
  20
  21     <para>Generally applications should present controls to the user
  22 without assumptions about their purpose. Each control comes with a
  23 name string the user is supposed to understand. When the purpose is
  24 non-intuitive the driver writer should provide a user manual, a user
  25 interface plug-in or a driver specific panel application. Predefined
  26 IDs were introduced to change a few controls programmatically, for
  27 example to mute a device during a channel switch.</para>
  28
  29     <para>Drivers may enumerate different controls after switching
  30 the current video input or output, tuner or modulator, or audio input
  31 or output. Different in the sense of other bounds, another default and
  32 current value, step size or other menu items. A control with a certain
  33 <emphasis>custom</emphasis> ID can also change name and
  34 type.<footnote>
  35         <para>It will be more convenient for applications if drivers
  36 make use of the <constant>V4L2_CTRL_FLAG_DISABLED</constant> flag, but
  37 that was never required.</para>
  38       </footnote> Control values are stored globally, they do not
  39 change when switching except to stay within the reported bounds. They
  40 also do not change &eg; when the device is opened or closed, when the
  41 tuner radio frequency is changed or generally never without
  42 application request. Since V4L2 specifies no event mechanism, panel
  43 applications intended to cooperate with other panel applications (be
  44 they built into a larger application, as a TV viewer) may need to
  45 regularly poll control values to update their user
  46 interface.<footnote>
  47         <para>Applications could call an ioctl to request events.
  48 After another process called &VIDIOC-S-CTRL; or another ioctl changing
  49 shared properties the &func-select; function would indicate
  50 readability until any ioctl (querying the properties) is
  51 called.</para>
  52       </footnote></para>
  53
  54     <para>
  55       All controls use machine endianness.
  56     </para>
  57
  58     <table pgwide="1" frame="none" id="control-id">
  59       <title>Control IDs</title>
  60       <tgroup cols="3">
  61         &cs-def;
  62         <thead>
  63           <row>
  64             <entry>ID</entry>
  65             <entry>Type</entry>
  66             <entry>Description</entry>
  67           </row>
  68         </thead>
  69         <tbody valign="top">
  70           <row>
  71             <entry><constant>V4L2_CID_BASE</constant></entry>
  72             <entry></entry>
  73             <entry>First predefined ID, equal to
  74 <constant>V4L2_CID_BRIGHTNESS</constant>.</entry>
  75           </row>
  76           <row>
  77             <entry><constant>V4L2_CID_USER_BASE</constant></entry>
  78             <entry></entry>
  79             <entry>Synonym of <constant>V4L2_CID_BASE</constant>.</entry>
  80           </row>
  81           <row>
  82             <entry><constant>V4L2_CID_BRIGHTNESS</constant></entry>
  83             <entry>integer</entry>
  84             <entry>Picture brightness, or more precisely, the black
  85 level.</entry>
  86           </row>
  87           <row>
  88             <entry><constant>V4L2_CID_CONTRAST</constant></entry>
  89             <entry>integer</entry>
  90             <entry>Picture contrast or luma gain.</entry>
  91           </row>
  92           <row>
  93             <entry><constant>V4L2_CID_SATURATION</constant></entry>
  94             <entry>integer</entry>
  95             <entry>Picture color saturation or chroma gain.</entry>
  96           </row>
  97           <row>
  98             <entry><constant>V4L2_CID_HUE</constant></entry>
  99             <entry>integer</entry>
 100             <entry>Hue or color balance.</entry>
 101           </row>
 102           <row>
 103             <entry><constant>V4L2_CID_AUDIO_VOLUME</constant></entry>
 104             <entry>integer</entry>
 105             <entry>Overall audio volume. Note some drivers also
 106 provide an OSS or ALSA mixer interface.</entry>
 107           </row>
 108           <row>
 109             <entry><constant>V4L2_CID_AUDIO_BALANCE</constant></entry>
 110             <entry>integer</entry>
 111             <entry>Audio stereo balance. Minimum corresponds to all
 112 the way left, maximum to right.</entry>
 113           </row>
 114           <row>
 115             <entry><constant>V4L2_CID_AUDIO_BASS</constant></entry>
 116             <entry>integer</entry>
 117             <entry>Audio bass adjustment.</entry>
 118           </row>
 119           <row>
 120             <entry><constant>V4L2_CID_AUDIO_TREBLE</constant></entry>
 121             <entry>integer</entry>
 122             <entry>Audio treble adjustment.</entry>
 123           </row>
 124           <row>
 125             <entry><constant>V4L2_CID_AUDIO_MUTE</constant></entry>
 126             <entry>boolean</entry>
 127             <entry>Mute audio, &ie; set the volume to zero, however
 128 without affecting <constant>V4L2_CID_AUDIO_VOLUME</constant>. Like
 129 ALSA drivers, V4L2 drivers must mute at load time to avoid excessive
 130 noise. Actually the entire device should be reset to a low power
 131 consumption state.</entry>
 132           </row>
 133           <row>
 134             <entry><constant>V4L2_CID_AUDIO_LOUDNESS</constant></entry>
 135             <entry>boolean</entry>
 136             <entry>Loudness mode (bass boost).</entry>
 137           </row>
 138           <row>
 139             <entry><constant>V4L2_CID_BLACK_LEVEL</constant></entry>
 140             <entry>integer</entry>
 141             <entry>Another name for brightness (not a synonym of
 142 <constant>V4L2_CID_BRIGHTNESS</constant>). This control is deprecated
 143 and should not be used in new drivers and applications.</entry>
 144           </row>
 145           <row>
 146             <entry><constant>V4L2_CID_AUTO_WHITE_BALANCE</constant></entry>
 147             <entry>boolean</entry>
 148             <entry>Automatic white balance (cameras).</entry>
 149           </row>
 150           <row>
 151             <entry><constant>V4L2_CID_DO_WHITE_BALANCE</constant></entry>
 152             <entry>button</entry>
 153             <entry>This is an action control. When set (the value is
 154 ignored), the device will do a white balance and then hold the current
 155 setting. Contrast this with the boolean
 156 <constant>V4L2_CID_AUTO_WHITE_BALANCE</constant>, which, when
 157 activated, keeps adjusting the white balance.</entry>
 158           </row>
 159           <row>
 160             <entry><constant>V4L2_CID_RED_BALANCE</constant></entry>
 161             <entry>integer</entry>
 162             <entry>Red chroma balance.</entry>
 163           </row>
 164           <row>
 165             <entry><constant>V4L2_CID_BLUE_BALANCE</constant></entry>
 166             <entry>integer</entry>
 167             <entry>Blue chroma balance.</entry>
 168           </row>
 169           <row>
 170             <entry><constant>V4L2_CID_GAMMA</constant></entry>
 171             <entry>integer</entry>
 172             <entry>Gamma adjust.</entry>
 173           </row>
 174           <row>
 175             <entry><constant>V4L2_CID_WHITENESS</constant></entry>
 176             <entry>integer</entry>
 177             <entry>Whiteness for grey-scale devices. This is a synonym
 178 for <constant>V4L2_CID_GAMMA</constant>. This control is deprecated
 179 and should not be used in new drivers and applications.</entry>
 180           </row>
 181           <row>
 182             <entry><constant>V4L2_CID_EXPOSURE</constant></entry>
 183             <entry>integer</entry>
 184             <entry>Exposure (cameras). [Unit?]</entry>
 185           </row>
 186           <row>
 187             <entry><constant>V4L2_CID_AUTOGAIN</constant></entry>
 188             <entry>boolean</entry>
 189             <entry>Automatic gain/exposure control.</entry>
 190           </row>
 191           <row>
 192             <entry><constant>V4L2_CID_GAIN</constant></entry>
 193             <entry>integer</entry>
 194             <entry>Gain control.</entry>
 195           </row>
 196           <row>
 197             <entry><constant>V4L2_CID_HFLIP</constant></entry>
 198             <entry>boolean</entry>
 199             <entry>Mirror the picture horizontally.</entry>
 200           </row>
 201           <row>
 202             <entry><constant>V4L2_CID_VFLIP</constant></entry>
 203             <entry>boolean</entry>
 204             <entry>Mirror the picture vertically.</entry>
 205           </row>
 206         <row>
 207           <entry><constant>V4L2_CID_HCENTER_DEPRECATED</constant> (formerly <constant>V4L2_CID_HCENTER</constant>)</entry>
 208             <entry>integer</entry>
 209             <entry>Horizontal image centering. This control is
 210 deprecated. New drivers and applications should use the <link
 211 linkend="camera-controls">Camera class controls</link>
 212 <constant>V4L2_CID_PAN_ABSOLUTE</constant>,
 213 <constant>V4L2_CID_PAN_RELATIVE</constant> and
 214 <constant>V4L2_CID_PAN_RESET</constant> instead.</entry>
 215           </row>
 216           <row>
 217             <entry><constant>V4L2_CID_VCENTER_DEPRECATED</constant>
 218             (formerly <constant>V4L2_CID_VCENTER</constant>)</entry>
 219             <entry>integer</entry>
 220             <entry>Vertical image centering. Centering is intended to
 221 <emphasis>physically</emphasis> adjust cameras. For image cropping see
 222 <xref linkend="crop" />, for clipping <xref linkend="overlay" />. This
 223 control is deprecated. New drivers and applications should use the
 224 <link linkend="camera-controls">Camera class controls</link>
 225 <constant>V4L2_CID_TILT_ABSOLUTE</constant>,
 226 <constant>V4L2_CID_TILT_RELATIVE</constant> and
 227 <constant>V4L2_CID_TILT_RESET</constant> instead.</entry>
 228           </row>
 229           <row id="v4l2-power-line-frequency">
 230             <entry><constant>V4L2_CID_POWER_LINE_FREQUENCY</constant></entry>
 231             <entry>enum</entry>
 232             <entry>Enables a power line frequency filter to avoid
 233 flicker. Possible values for <constant>enum v4l2_power_line_frequency</constant> are:
 234 <constant>V4L2_CID_POWER_LINE_FREQUENCY_DISABLED</constant> (0),
 235 <constant>V4L2_CID_POWER_LINE_FREQUENCY_50HZ</constant> (1),
 236 <constant>V4L2_CID_POWER_LINE_FREQUENCY_60HZ</constant> (2) and
 237 <constant>V4L2_CID_POWER_LINE_FREQUENCY_AUTO</constant> (3).</entry>
 238           </row>
 239           <row>
 240             <entry><constant>V4L2_CID_HUE_AUTO</constant></entry>
 241             <entry>boolean</entry>
 242             <entry>Enables automatic hue control by the device. The
 243 effect of setting <constant>V4L2_CID_HUE</constant> while automatic
 244 hue control is enabled is undefined, drivers should ignore such
 245 request.</entry>
 246           </row>
 247           <row>
 248             <entry><constant>V4L2_CID_WHITE_BALANCE_TEMPERATURE</constant></entry>
 249             <entry>integer</entry>
 250             <entry>This control specifies the white balance settings
 251 as a color temperature in Kelvin. A driver should have a minimum of
 252 2800 (incandescent) to 6500 (daylight). For more information about
 253 color temperature see <ulink
 254 url="http://en.wikipedia.org/wiki/Color_temperature">Wikipedia</ulink>.</entry>
 255           </row>
 256           <row>
 257             <entry><constant>V4L2_CID_SHARPNESS</constant></entry>
 258             <entry>integer</entry>
 259             <entry>Adjusts the sharpness filters in a camera. The
 260 minimum value disables the filters, higher values give a sharper
 261 picture.</entry>
 262           </row>
 263           <row>
 264             <entry><constant>V4L2_CID_BACKLIGHT_COMPENSATION</constant></entry>
 265             <entry>integer</entry>
 266             <entry>Adjusts the backlight compensation in a camera. The
 267 minimum value disables backlight compensation.</entry>
 268           </row>
 269           <row>
 270             <entry><constant>V4L2_CID_CHROMA_AGC</constant></entry>
 271             <entry>boolean</entry>
 272             <entry>Chroma automatic gain control.</entry>
 273           </row>
 274           <row>
 275             <entry><constant>V4L2_CID_CHROMA_GAIN</constant></entry>
 276             <entry>integer</entry>
 277             <entry>Adjusts the Chroma gain control (for use when chroma AGC
 278             is disabled).</entry>
 279           </row>
 280           <row>
 281             <entry><constant>V4L2_CID_COLOR_KILLER</constant></entry>
 282             <entry>boolean</entry>
 283             <entry>Enable the color killer (&ie; force a black &amp; white image in case of a weak video signal).</entry>
 284           </row>
 285           <row id="v4l2-colorfx">
 286             <entry><constant>V4L2_CID_COLORFX</constant></entry>
 287             <entry>enum</entry>
 288             <entry>Selects a color effect. Possible values for
 289 <constant>enum v4l2_colorfx</constant> are:
 290 <constant>V4L2_COLORFX_NONE</constant> (0),
 291 <constant>V4L2_COLORFX_BW</constant> (1),
 292 <constant>V4L2_COLORFX_SEPIA</constant> (2),
 293 <constant>V4L2_COLORFX_NEGATIVE</constant> (3),
 294 <constant>V4L2_COLORFX_EMBOSS</constant> (4),
 295 <constant>V4L2_COLORFX_SKETCH</constant> (5),
 296 <constant>V4L2_COLORFX_SKY_BLUE</constant> (6),
 297 <constant>V4L2_COLORFX_GRASS_GREEN</constant> (7),
 298 <constant>V4L2_COLORFX_SKIN_WHITEN</constant> (8) and
 299 <constant>V4L2_COLORFX_VIVID</constant> (9).</entry>
 300           </row>
 301           <row>
 302             <entry><constant>V4L2_CID_ROTATE</constant></entry>
 303             <entry>integer</entry>
 304             <entry>Rotates the image by specified angle. Common angles are 90,
 305             270 and 180. Rotating the image to 90 and 270 will reverse the height
 306             and width of the display window. It is necessary to set the new height and
 307             width of the picture using the &VIDIOC-S-FMT; ioctl according to
 308             the rotation angle selected.</entry>
 309           </row>
 310           <row>
 311             <entry><constant>V4L2_CID_BG_COLOR</constant></entry>
 312             <entry>integer</entry>
 313             <entry>Sets the background color on the current output device.
 314             Background color needs to be specified in the RGB24 format. The
 315             supplied 32 bit value is interpreted as bits 0-7 Red color information,
 316             bits 8-15 Green color information, bits 16-23 Blue color
 317             information and bits 24-31 must be zero.</entry>
 318           </row>
 319           <row>
 320             <entry><constant>V4L2_CID_ILLUMINATORS_1</constant>
 321                 <constant>V4L2_CID_ILLUMINATORS_2</constant></entry>
 322             <entry>boolean</entry>
 323             <entry>Switch on or off the illuminator 1 or 2 of the device
 324                 (usually a microscope).</entry>
 325           </row>
 326           <row>
 327             <entry><constant>V4L2_CID_MIN_BUFFERS_FOR_CAPTURE</constant></entry>
 328             <entry>integer</entry>
 329             <entry>This is a read-only control that can be read by the application
 330 and used as a hint to determine the number of CAPTURE buffers to pass to REQBUFS.
 331 The value is the minimum number of CAPTURE buffers that is necessary for hardware
 332 to work.</entry>
 333           </row>
 334           <row>
 335             <entry><constant>V4L2_CID_MIN_BUFFERS_FOR_OUTPUT</constant></entry>
 336             <entry>integer</entry>
 337             <entry>This is a read-only control that can be read by the application
 338 and used as a hint to determine the number of OUTPUT buffers to pass to REQBUFS.
 339 The value is the minimum number of OUTPUT buffers that is necessary for hardware
 340 to work.</entry>
 341           </row>
 342           <row id="v4l2-alpha-component">
 343             <entry><constant>V4L2_CID_ALPHA_COMPONENT</constant></entry>
 344             <entry>integer</entry>
 345             <entry> Sets the alpha color component on the capture device or on
 346             the capture buffer queue of a mem-to-mem device. When a mem-to-mem
 347             device produces frame format that includes an alpha component
 348             (e.g. <link linkend="rgb-formats">packed RGB image formats</link>)
 349             and the alpha value is not defined by the mem-to-mem input data
 350             this control lets you select the alpha component value of all
 351             pixels. It is applicable to any pixel format that contains an alpha
 352             component.
 353             </entry>
 354           </row>
 355           <row>
 356             <entry><constant>V4L2_CID_LASTP1</constant></entry>
 357             <entry></entry>
 358             <entry>End of the predefined control IDs (currently
 359               <constant>V4L2_CID_ALPHA_COMPONENT</constant> + 1).</entry>
 360           </row>
 361           <row>
 362             <entry><constant>V4L2_CID_PRIVATE_BASE</constant></entry>
 363             <entry></entry>
 364             <entry>ID of the first custom (driver specific) control.
 365 Applications depending on particular custom controls should check the
 366 driver name and version, see <xref linkend="querycap" />.</entry>
 367           </row>
 368         </tbody>
 369       </tgroup>
 370     </table>
 371
 372     <para>Applications can enumerate the available controls with the
 373 &VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls, get and set a
 374 control value with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls.
 375 Drivers must implement <constant>VIDIOC_QUERYCTRL</constant>,
 376 <constant>VIDIOC_G_CTRL</constant> and
 377 <constant>VIDIOC_S_CTRL</constant> when the device has one or more
 378 controls, <constant>VIDIOC_QUERYMENU</constant> when it has one or
 379 more menu type controls.</para>
 380
 381     <example>
 382       <title>Enumerating all controls</title>
 383
 384       <programlisting>
 385 &v4l2-queryctrl; queryctrl;
 386 &v4l2-querymenu; querymenu;
 387
 388 static void
 389 enumerate_menu (void)
 390 {
 391         printf ("  Menu items:\n");
 392
 393         memset (&amp;querymenu, 0, sizeof (querymenu));
 394         querymenu.id = queryctrl.id;
 395
 396         for (querymenu.index = queryctrl.minimum;
 397              querymenu.index &lt;= queryctrl.maximum;
 398               querymenu.index++) {
 399                 if (0 == ioctl (fd, &VIDIOC-QUERYMENU;, &amp;querymenu)) {
 400                         printf ("  %s\n", querymenu.name);
 401                 }
 402         }
 403 }
 404
 405 memset (&amp;queryctrl, 0, sizeof (queryctrl));
 406
 407 for (queryctrl.id = V4L2_CID_BASE;
 408      queryctrl.id &lt; V4L2_CID_LASTP1;
 409      queryctrl.id++) {
 410         if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;queryctrl)) {
 411                 if (queryctrl.flags &amp; V4L2_CTRL_FLAG_DISABLED)
 412                         continue;
 413
 414                 printf ("Control %s\n", queryctrl.name);
 415
 416                 if (queryctrl.type == V4L2_CTRL_TYPE_MENU)
 417                         enumerate_menu ();
 418         } else {
 419                 if (errno == EINVAL)
 420                         continue;
 421
 422                 perror ("VIDIOC_QUERYCTRL");
 423                 exit (EXIT_FAILURE);
 424         }
 425 }
 426
 427 for (queryctrl.id = V4L2_CID_PRIVATE_BASE;;
 428      queryctrl.id++) {
 429         if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;queryctrl)) {
 430                 if (queryctrl.flags &amp; V4L2_CTRL_FLAG_DISABLED)
 431                         continue;
 432
 433                 printf ("Control %s\n", queryctrl.name);
 434
 435                 if (queryctrl.type == V4L2_CTRL_TYPE_MENU)
 436                         enumerate_menu ();
 437         } else {
 438                 if (errno == EINVAL)
 439                         break;
 440
 441                 perror ("VIDIOC_QUERYCTRL");
 442                 exit (EXIT_FAILURE);
 443         }
 444 }
 445 </programlisting>
 446     </example>
 447
 448     <example>
 449       <title>Changing controls</title>
 450
 451       <programlisting>
 452 &v4l2-queryctrl; queryctrl;
 453 &v4l2-control; control;
 454
 455 memset (&amp;queryctrl, 0, sizeof (queryctrl));
 456 queryctrl.id = V4L2_CID_BRIGHTNESS;
 457
 458 if (-1 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;queryctrl)) {
 459         if (errno != EINVAL) {
 460                 perror ("VIDIOC_QUERYCTRL");
 461                 exit (EXIT_FAILURE);
 462         } else {
 463                 printf ("V4L2_CID_BRIGHTNESS is not supported\n");
 464         }
 465 } else if (queryctrl.flags &amp; V4L2_CTRL_FLAG_DISABLED) {
 466         printf ("V4L2_CID_BRIGHTNESS is not supported\n");
 467 } else {
 468         memset (&amp;control, 0, sizeof (control));
 469         control.id = V4L2_CID_BRIGHTNESS;
 470         control.value = queryctrl.default_value;
 471
 472         if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &amp;control)) {
 473                 perror ("VIDIOC_S_CTRL");
 474                 exit (EXIT_FAILURE);
 475         }
 476 }
 477
 478 memset (&amp;control, 0, sizeof (control));
 479 control.id = V4L2_CID_CONTRAST;
 480
 481 if (0 == ioctl (fd, &VIDIOC-G-CTRL;, &amp;control)) {
 482         control.value += 1;
 483
 484         /* The driver may clamp the value or return ERANGE, ignored here */
 485
 486         if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &amp;control)
 487             &amp;&amp; errno != ERANGE) {
 488                 perror ("VIDIOC_S_CTRL");
 489                 exit (EXIT_FAILURE);
 490         }
 491 /* Ignore if V4L2_CID_CONTRAST is unsupported */
 492 } else if (errno != EINVAL) {
 493         perror ("VIDIOC_G_CTRL");
 494         exit (EXIT_FAILURE);
 495 }
 496
 497 control.id = V4L2_CID_AUDIO_MUTE;
 498 control.value = TRUE; /* silence */
 499
 500 /* Errors ignored */
 501 ioctl (fd, VIDIOC_S_CTRL, &amp;control);
 502 </programlisting>
 503     </example>
 504   </section>
 505
 506   <section id="extended-controls">
 507     <title>Extended Controls</title>
 508
 509     <section>
 510       <title>Introduction</title>
 511
 512       <para>The control mechanism as originally designed was meant
 513 to be used for user settings (brightness, saturation, etc). However,
 514 it turned out to be a very useful model for implementing more
 515 complicated driver APIs where each driver implements only a subset of
 516 a larger API.</para>
 517
 518       <para>The MPEG encoding API was the driving force behind
 519 designing and implementing this extended control mechanism: the MPEG
 520 standard is quite large and the currently supported hardware MPEG
 521 encoders each only implement a subset of this standard. Further more,
 522 many parameters relating to how the video is encoded into an MPEG
 523 stream are specific to the MPEG encoding chip since the MPEG standard
 524 only defines the format of the resulting MPEG stream, not how the
 525 video is actually encoded into that format.</para>
 526
 527       <para>Unfortunately, the original control API lacked some
 528 features needed for these new uses and so it was extended into the
 529 (not terribly originally named) extended control API.</para>
 530
 531       <para>Even though the MPEG encoding API was the first effort
 532 to use the Extended Control API, nowadays there are also other classes
 533 of Extended Controls, such as Camera Controls and FM Transmitter Controls.
 534 The Extended Controls API as well as all Extended Controls classes are
 535 described in the following text.</para>
 536     </section>
 537
 538     <section>
 539       <title>The Extended Control API</title>
 540
 541       <para>Three new ioctls are available: &VIDIOC-G-EXT-CTRLS;,
 542 &VIDIOC-S-EXT-CTRLS; and &VIDIOC-TRY-EXT-CTRLS;. These ioctls act on
 543 arrays of controls (as opposed to the &VIDIOC-G-CTRL; and
 544 &VIDIOC-S-CTRL; ioctls that act on a single control). This is needed
 545 since it is often required to atomically change several controls at
 546 once.</para>
 547
 548       <para>Each of the new ioctls expects a pointer to a
 549 &v4l2-ext-controls;. This structure contains a pointer to the control
 550 array, a count of the number of controls in that array and a control
 551 class. Control classes are used to group similar controls into a
 552 single class. For example, control class
 553 <constant>V4L2_CTRL_CLASS_USER</constant> contains all user controls
 554 (&ie; all controls that can also be set using the old
 555 <constant>VIDIOC_S_CTRL</constant> ioctl). Control class
 556 <constant>V4L2_CTRL_CLASS_MPEG</constant> contains all controls
 557 relating to MPEG encoding, etc.</para>
 558
 559       <para>All controls in the control array must belong to the
 560 specified control class. An error is returned if this is not the
 561 case.</para>
 562
 563       <para>It is also possible to use an empty control array (count
 564 == 0) to check whether the specified control class is
 565 supported.</para>
 566
 567       <para>The control array is a &v4l2-ext-control; array. The
 568 <structname>v4l2_ext_control</structname> structure is very similar to
 569 &v4l2-control;, except for the fact that it also allows for 64-bit
 570 values and pointers to be passed.</para>
 571
 572       <para>It is important to realize that due to the flexibility of
 573 controls it is necessary to check whether the control you want to set
 574 actually is supported in the driver and what the valid range of values
 575 is. So use the &VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls to
 576 check this. Also note that it is possible that some of the menu
 577 indices in a control of type <constant>V4L2_CTRL_TYPE_MENU</constant>
 578 may not be supported (<constant>VIDIOC_QUERYMENU</constant> will
 579 return an error). A good example is the list of supported MPEG audio
 580 bitrates. Some drivers only support one or two bitrates, others
 581 support a wider range.</para>
 582
 583       <para>
 584         All controls use machine endianness.
 585       </para>
 586     </section>
 587
 588     <section>
 589       <title>Enumerating Extended Controls</title>
 590
 591       <para>The recommended way to enumerate over the extended
 592 controls is by using &VIDIOC-QUERYCTRL; in combination with the
 593 <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> flag:</para>
 594
 595       <informalexample>
 596         <programlisting>
 597 &v4l2-queryctrl; qctrl;
 598
 599 qctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL;
 600 while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;qctrl)) {
 601         /* ... */
 602         qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
 603 }
 604 </programlisting>
 605       </informalexample>
 606
 607       <para>The initial control ID is set to 0 ORed with the
 608 <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> flag. The
 609 <constant>VIDIOC_QUERYCTRL</constant> ioctl will return the first
 610 control with a higher ID than the specified one. When no such controls
 611 are found an error is returned.</para>
 612
 613       <para>If you want to get all controls within a specific control
 614 class, then you can set the initial
 615 <structfield>qctrl.id</structfield> value to the control class and add
 616 an extra check to break out of the loop when a control of another
 617 control class is found:</para>
 618
 619       <informalexample>
 620         <programlisting>
 621 qctrl.id = V4L2_CTRL_CLASS_MPEG | V4L2_CTRL_FLAG_NEXT_CTRL;
 622 while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;qctrl)) {
 623         if (V4L2_CTRL_ID2CLASS (qctrl.id) != V4L2_CTRL_CLASS_MPEG)
 624                 break;
 625                 /* ... */
 626                 qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
 627         }
 628 </programlisting>
 629       </informalexample>
 630
 631       <para>The 32-bit <structfield>qctrl.id</structfield> value is
 632 subdivided into three bit ranges: the top 4 bits are reserved for
 633 flags (&eg; <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant>) and are not
 634 actually part of the ID. The remaining 28 bits form the control ID, of
 635 which the most significant 12 bits define the control class and the
 636 least significant 16 bits identify the control within the control
 637 class. It is guaranteed that these last 16 bits are always non-zero
 638 for controls. The range of 0x1000 and up are reserved for
 639 driver-specific controls. The macro
 640 <constant>V4L2_CTRL_ID2CLASS(id)</constant> returns the control class
 641 ID based on a control ID.</para>
 642
 643       <para>If the driver does not support extended controls, then
 644 <constant>VIDIOC_QUERYCTRL</constant> will fail when used in
 645 combination with <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant>. In
 646 that case the old method of enumerating control should be used (see
 647 1.8). But if it is supported, then it is guaranteed to enumerate over
 648 all controls, including driver-private controls.</para>
 649     </section>
 650
 651     <section>
 652       <title>Creating Control Panels</title>
 653
 654       <para>It is possible to create control panels for a graphical
 655 user interface where the user can select the various controls.
 656 Basically you will have to iterate over all controls using the method
 657 described above. Each control class starts with a control of type
 658 <constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant>.
 659 <constant>VIDIOC_QUERYCTRL</constant> will return the name of this
 660 control class which can be used as the title of a tab page within a
 661 control panel.</para>
 662
 663       <para>The flags field of &v4l2-queryctrl; also contains hints on
 664 the behavior of the control. See the &VIDIOC-QUERYCTRL; documentation
 665 for more details.</para>
 666     </section>
 667
 668     <section id="mpeg-controls">
 669       <title>MPEG Control Reference</title>
 670
 671       <para>Below all controls within the MPEG control class are
 672 described. First the generic controls, then controls specific for
 673 certain hardware.</para>
 674
 675       <section>
 676         <title>Generic MPEG Controls</title>
 677
 678         <table pgwide="1" frame="none" id="mpeg-control-id">
 679           <title>MPEG Control IDs</title>
 680           <tgroup cols="4">
 681             <colspec colname="c1" colwidth="1*" />
 682             <colspec colname="c2" colwidth="6*" />
 683             <colspec colname="c3" colwidth="2*" />
 684             <colspec colname="c4" colwidth="6*" />
 685             <spanspec namest="c1" nameend="c2" spanname="id" />
 686             <spanspec namest="c2" nameend="c4" spanname="descr" />
 687             <thead>
 688               <row>
 689                 <entry spanname="id" align="left">ID</entry>
 690                 <entry align="left">Type</entry>
 691               </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
 692               </row>
 693             </thead>
 694             <tbody valign="top">
 695               <row><entry></entry></row>
 696               <row>
 697                 <entry spanname="id"><constant>V4L2_CID_MPEG_CLASS</constant>&nbsp;</entry>
 698                 <entry>class</entry>
 699               </row><row><entry spanname="descr">The MPEG class
 700 descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a
 701 description of this control class. This description can be used as the
 702 caption of a Tab page in a GUI, for example.</entry>
 703               </row>
 704               <row><entry></entry></row>
 705               <row id="v4l2-mpeg-stream-type">
 706                 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_TYPE</constant>&nbsp;</entry>
 707                 <entry>enum&nbsp;v4l2_mpeg_stream_type</entry>
 708               </row><row><entry spanname="descr">The MPEG-1, -2 or -4
 709 output stream type. One cannot assume anything here. Each hardware
 710 MPEG encoder tends to support different subsets of the available MPEG
 711 stream types. This control is specific to multiplexed MPEG streams.
 712 The currently defined stream types are:</entry>
 713               </row>
 714               <row>
 715                 <entrytbl spanname="descr" cols="2">
 716                   <tbody valign="top">
 717                     <row>
 718                       <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_PS</constant>&nbsp;</entry>
 719                       <entry>MPEG-2 program stream</entry>
 720                     </row>
 721                     <row>
 722                       <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_TS</constant>&nbsp;</entry>
 723                       <entry>MPEG-2 transport stream</entry>
 724                     </row>
 725                     <row>
 726                       <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG1_SS</constant>&nbsp;</entry>
 727                       <entry>MPEG-1 system stream</entry>
 728                     </row>
 729                     <row>
 730                       <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_DVD</constant>&nbsp;</entry>
 731                       <entry>MPEG-2 DVD-compatible stream</entry>
 732                     </row>
 733                     <row>
 734                       <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG1_VCD</constant>&nbsp;</entry>
 735                       <entry>MPEG-1 VCD-compatible stream</entry>
 736                     </row>
 737                     <row>
 738                       <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_SVCD</constant>&nbsp;</entry>
 739                       <entry>MPEG-2 SVCD-compatible stream</entry>
 740                     </row>
 741                   </tbody>
 742                 </entrytbl>
 743               </row>
 744               <row><entry></entry></row>
 745               <row>
 746                 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_PMT</constant>&nbsp;</entry>
 747                 <entry>integer</entry>
 748               </row><row><entry spanname="descr">Program Map Table
 749 Packet ID for the MPEG transport stream (default 16)</entry>
 750               </row>
 751               <row><entry></entry></row>
 752               <row>
 753                 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_AUDIO</constant>&nbsp;</entry>
 754                 <entry>integer</entry>
 755               </row><row><entry spanname="descr">Audio Packet ID for
 756 the MPEG transport stream (default 256)</entry>
 757               </row>
 758               <row><entry></entry></row>
 759               <row>
 760                 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_VIDEO</constant>&nbsp;</entry>
 761                 <entry>integer</entry>
 762               </row><row><entry spanname="descr">Video Packet ID for
 763 the MPEG transport stream (default 260)</entry>
 764               </row>
 765               <row><entry></entry></row>
 766               <row>
 767                 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_PCR</constant>&nbsp;</entry>
 768                 <entry>integer</entry>
 769               </row><row><entry spanname="descr">Packet ID for the
 770 MPEG transport stream carrying PCR fields (default 259)</entry>
 771               </row>
 772               <row><entry></entry></row>
 773               <row>
 774                 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PES_ID_AUDIO</constant>&nbsp;</entry>
 775                 <entry>integer</entry>
 776               </row><row><entry spanname="descr">Audio ID for MPEG
 777 PES</entry>
 778               </row>
 779               <row><entry></entry></row>
 780               <row>
 781                 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PES_ID_VIDEO</constant>&nbsp;</entry>
 782                 <entry>integer</entry>
 783               </row><row><entry spanname="descr">Video ID for MPEG
 784 PES</entry>
 785               </row>
 786               <row><entry></entry></row>
 787               <row id="v4l2-mpeg-stream-vbi-fmt">
 788                 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_VBI_FMT</constant>&nbsp;</entry>
 789                 <entry>enum&nbsp;v4l2_mpeg_stream_vbi_fmt</entry>
 790               </row><row><entry spanname="descr">Some cards can embed
 791 VBI data (&eg; Closed Caption, Teletext) into the MPEG stream. This
 792 control selects whether VBI data should be embedded, and if so, what
 793 embedding method should be used. The list of possible VBI formats
 794 depends on the driver. The currently defined VBI format types
 795 are:</entry>
 796               </row>
 797               <row>
 798                 <entrytbl spanname="descr" cols="2">
 799                   <tbody valign="top">
 800                     <row>
 801                       <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_NONE</constant>&nbsp;</entry>
 802                       <entry>No VBI in the MPEG stream</entry>
 803                     </row>
 804                     <row>
 805                       <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_IVTV</constant>&nbsp;</entry>
 806                       <entry>VBI in private packets, IVTV format (documented
 807 in the kernel sources in the file <filename>Documentation/video4linux/cx2341x/README.vbi</filename>)</entry>
 808                     </row>
 809                   </tbody>
 810                 </entrytbl>
 811               </row>
 812               <row><entry></entry></row>
 813               <row id="v4l2-mpeg-audio-sampling-freq">
 814                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ</constant>&nbsp;</entry>
 815                 <entry>enum&nbsp;v4l2_mpeg_audio_sampling_freq</entry>
 816               </row><row><entry spanname="descr">MPEG Audio sampling
 817 frequency. Possible values are:</entry>
 818               </row>
 819               <row>
 820                 <entrytbl spanname="descr" cols="2">
 821                   <tbody valign="top">
 822                     <row>
 823                       <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_44100</constant>&nbsp;</entry>
 824                       <entry>44.1 kHz</entry>
 825                     </row>
 826                     <row>
 827                       <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_48000</constant>&nbsp;</entry>
 828                       <entry>48 kHz</entry>
 829                     </row>
 830                     <row>
 831                       <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_32000</constant>&nbsp;</entry>
 832                       <entry>32 kHz</entry>
 833                     </row>
 834                   </tbody>
 835                 </entrytbl>
 836               </row>
 837               <row><entry></entry></row>
 838               <row id="v4l2-mpeg-audio-encoding">
 839                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_ENCODING</constant>&nbsp;</entry>
 840                 <entry>enum&nbsp;v4l2_mpeg_audio_encoding</entry>
 841               </row><row><entry spanname="descr">MPEG Audio encoding.
 842 This control is specific to multiplexed MPEG streams.
 843 Possible values are:</entry>
 844               </row>
 845               <row>
 846                 <entrytbl spanname="descr" cols="2">
 847                   <tbody valign="top">
 848                     <row>
 849                       <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_1</constant>&nbsp;</entry>
 850                       <entry>MPEG-1/2 Layer I encoding</entry>
 851                     </row>
 852                     <row>
 853                       <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_2</constant>&nbsp;</entry>
 854                       <entry>MPEG-1/2 Layer II encoding</entry>
 855                     </row>
 856                     <row>
 857                       <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_3</constant>&nbsp;</entry>
 858                       <entry>MPEG-1/2 Layer III encoding</entry>
 859                     </row>
 860                     <row>
 861                       <entry><constant>V4L2_MPEG_AUDIO_ENCODING_AAC</constant>&nbsp;</entry>
 862                       <entry>MPEG-2/4 AAC (Advanced Audio Coding)</entry>
 863                     </row>
 864                     <row>
 865                       <entry><constant>V4L2_MPEG_AUDIO_ENCODING_AC3</constant>&nbsp;</entry>
 866                       <entry>AC-3 aka ATSC A/52 encoding</entry>
 867                     </row>
 868                   </tbody>
 869                 </entrytbl>
 870               </row>
 871               <row><entry></entry></row>
 872               <row id="v4l2-mpeg-audio-l1-bitrate">
 873                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L1_BITRATE</constant>&nbsp;</entry>
 874                 <entry>enum&nbsp;v4l2_mpeg_audio_l1_bitrate</entry>
 875               </row><row><entry spanname="descr">MPEG-1/2 Layer I bitrate.
 876 Possible values are:</entry>
 877               </row>
 878               <row>
 879                 <entrytbl spanname="descr" cols="2">
 880                   <tbody valign="top">
 881                     <row>
 882                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_32K</constant>&nbsp;</entry>
 883                       <entry>32 kbit/s</entry></row>
 884                     <row>
 885                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_64K</constant>&nbsp;</entry>
 886                       <entry>64 kbit/s</entry>
 887                     </row>
 888                     <row>
 889                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_96K</constant>&nbsp;</entry>
 890                       <entry>96 kbit/s</entry>
 891                     </row>
 892                     <row>
 893                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_128K</constant>&nbsp;</entry>
 894                       <entry>128 kbit/s</entry>
 895                     </row>
 896                     <row>
 897                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_160K</constant>&nbsp;</entry>
 898                       <entry>160 kbit/s</entry>
 899                     </row>
 900                     <row>
 901                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_192K</constant>&nbsp;</entry>
 902                       <entry>192 kbit/s</entry>
 903                     </row>
 904                     <row>
 905                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_224K</constant>&nbsp;</entry>
 906                       <entry>224 kbit/s</entry>
 907                     </row>
 908                     <row>
 909                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_256K</constant>&nbsp;</entry>
 910                       <entry>256 kbit/s</entry>
 911                     </row>
 912                     <row>
 913                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_288K</constant>&nbsp;</entry>
 914                       <entry>288 kbit/s</entry>
 915                     </row>
 916                     <row>
 917                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_320K</constant>&nbsp;</entry>
 918                       <entry>320 kbit/s</entry>
 919                     </row>
 920                     <row>
 921                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_352K</constant>&nbsp;</entry>
 922                       <entry>352 kbit/s</entry>
 923                     </row>
 924                     <row>
 925                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_384K</constant>&nbsp;</entry>
 926                       <entry>384 kbit/s</entry>
 927                     </row>
 928                     <row>
 929                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_416K</constant>&nbsp;</entry>
 930                       <entry>416 kbit/s</entry>
 931                     </row>
 932                     <row>
 933                       <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_448K</constant>&nbsp;</entry>
 934                       <entry>448 kbit/s</entry>
 935                     </row>
 936                   </tbody>
 937                 </entrytbl>
 938               </row>
 939               <row><entry></entry></row>
 940               <row id="v4l2-mpeg-audio-l2-bitrate">
 941                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L2_BITRATE</constant>&nbsp;</entry>
 942                 <entry>enum&nbsp;v4l2_mpeg_audio_l2_bitrate</entry>
 943               </row><row><entry spanname="descr">MPEG-1/2 Layer II bitrate.
 944 Possible values are:</entry>
 945               </row>
 946               <row>
 947                 <entrytbl spanname="descr" cols="2">
 948                   <tbody valign="top">
 949                     <row>
 950                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_32K</constant>&nbsp;</entry>
 951                       <entry>32 kbit/s</entry>
 952                     </row>
 953                     <row>
 954                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_48K</constant>&nbsp;</entry>
 955                       <entry>48 kbit/s</entry>
 956                     </row>
 957                     <row>
 958                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_56K</constant>&nbsp;</entry>
 959                       <entry>56 kbit/s</entry>
 960                     </row>
 961                     <row>
 962                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_64K</constant>&nbsp;</entry>
 963                       <entry>64 kbit/s</entry>
 964                     </row>
 965                     <row>
 966                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_80K</constant>&nbsp;</entry>
 967                       <entry>80 kbit/s</entry>
 968                     </row>
 969                     <row>
 970                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_96K</constant>&nbsp;</entry>
 971                       <entry>96 kbit/s</entry>
 972                     </row>
 973                     <row>
 974                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_112K</constant>&nbsp;</entry>
 975                       <entry>112 kbit/s</entry>
 976                     </row>
 977                     <row>
 978                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_128K</constant>&nbsp;</entry>
 979                       <entry>128 kbit/s</entry>
 980                     </row>
 981                     <row>
 982                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_160K</constant>&nbsp;</entry>
 983                       <entry>160 kbit/s</entry>
 984                     </row>
 985                     <row>
 986                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_192K</constant>&nbsp;</entry>
 987                       <entry>192 kbit/s</entry>
 988                     </row>
 989                     <row>
 990                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_224K</constant>&nbsp;</entry>
 991                       <entry>224 kbit/s</entry>
 992                     </row>
 993                     <row>
 994                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_256K</constant>&nbsp;</entry>
 995                       <entry>256 kbit/s</entry>
 996                     </row>
 997                     <row>
 998                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_320K</constant>&nbsp;</entry>
 999                       <entry>320 kbit/s</entry>
1000                     </row>
1001                     <row>
1002                       <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_384K</constant>&nbsp;</entry>
1003                       <entry>384 kbit/s</entry>
1004                     </row>
1005                   </tbody>
1006                 </entrytbl>
1007               </row>
1008               <row><entry></entry></row>
1009               <row id="v4l2-mpeg-audio-l3-bitrate">
1010                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L3_BITRATE</constant>&nbsp;</entry>
1011                 <entry>enum&nbsp;v4l2_mpeg_audio_l3_bitrate</entry>
1012               </row><row><entry spanname="descr">MPEG-1/2 Layer III bitrate.
1013 Possible values are:</entry>
1014               </row>
1015               <row>
1016                 <entrytbl spanname="descr" cols="2">
1017                   <tbody valign="top">
1018                     <row>
1019                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_32K</constant>&nbsp;</entry>
1020                       <entry>32 kbit/s</entry>
1021                     </row>
1022                     <row>
1023                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_40K</constant>&nbsp;</entry>
1024                       <entry>40 kbit/s</entry>
1025                     </row>
1026                     <row>
1027                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_48K</constant>&nbsp;</entry>
1028                       <entry>48 kbit/s</entry>
1029                     </row>
1030                     <row>
1031                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_56K</constant>&nbsp;</entry>
1032                       <entry>56 kbit/s</entry>
1033                     </row>
1034                     <row>
1035                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_64K</constant>&nbsp;</entry>
1036                       <entry>64 kbit/s</entry>
1037                     </row>
1038                     <row>
1039                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_80K</constant>&nbsp;</entry>
1040                       <entry>80 kbit/s</entry>
1041                     </row>
1042                     <row>
1043                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_96K</constant>&nbsp;</entry>
1044                       <entry>96 kbit/s</entry>
1045                     </row>
1046                     <row>
1047                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_112K</constant>&nbsp;</entry>
1048                       <entry>112 kbit/s</entry>
1049                     </row>
1050                     <row>
1051                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_128K</constant>&nbsp;</entry>
1052                       <entry>128 kbit/s</entry>
1053                     </row>
1054                     <row>
1055                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_160K</constant>&nbsp;</entry>
1056                       <entry>160 kbit/s</entry>
1057                     </row>
1058                     <row>
1059                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_192K</constant>&nbsp;</entry>
1060                       <entry>192 kbit/s</entry>
1061                     </row>
1062                     <row>
1063                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_224K</constant>&nbsp;</entry>
1064                       <entry>224 kbit/s</entry>
1065                     </row>
1066                     <row>
1067                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_256K</constant>&nbsp;</entry>
1068                       <entry>256 kbit/s</entry>
1069                     </row>
1070                     <row>
1071                       <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_320K</constant>&nbsp;</entry>
1072                       <entry>320 kbit/s</entry>
1073                     </row>
1074                   </tbody>
1075                 </entrytbl>
1076               </row>
1077               <row><entry></entry></row>
1078               <row>
1079                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_AAC_BITRATE</constant>&nbsp;</entry>
1080                 <entry>integer</entry>
1081               </row><row><entry spanname="descr">AAC bitrate in bits per second.</entry>
1082               </row>
1083               <row><entry></entry></row>
1084               <row id="v4l2-mpeg-audio-ac3-bitrate">
1085                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_AC3_BITRATE</constant>&nbsp;</entry>
1086                 <entry>enum&nbsp;v4l2_mpeg_audio_ac3_bitrate</entry>
1087               </row><row><entry spanname="descr">AC-3 bitrate.
1088 Possible values are:</entry>
1089               </row>
1090               <row>
1091                 <entrytbl spanname="descr" cols="2">
1092                   <tbody valign="top">
1093                     <row>
1094                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_32K</constant>&nbsp;</entry>
1095                       <entry>32 kbit/s</entry>
1096                     </row>
1097                     <row>
1098                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_40K</constant>&nbsp;</entry>
1099                       <entry>40 kbit/s</entry>
1100                     </row>
1101                     <row>
1102                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_48K</constant>&nbsp;</entry>
1103                       <entry>48 kbit/s</entry>
1104                     </row>
1105                     <row>
1106                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_56K</constant>&nbsp;</entry>
1107                       <entry>56 kbit/s</entry>
1108                     </row>
1109                     <row>
1110                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_64K</constant>&nbsp;</entry>
1111                       <entry>64 kbit/s</entry>
1112                     </row>
1113                     <row>
1114                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_80K</constant>&nbsp;</entry>
1115                       <entry>80 kbit/s</entry>
1116                     </row>
1117                     <row>
1118                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_96K</constant>&nbsp;</entry>
1119                       <entry>96 kbit/s</entry>
1120                     </row>
1121                     <row>
1122                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_112K</constant>&nbsp;</entry>
1123                       <entry>112 kbit/s</entry>
1124                     </row>
1125                     <row>
1126                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_128K</constant>&nbsp;</entry>
1127                       <entry>128 kbit/s</entry>
1128                     </row>
1129                     <row>
1130                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_160K</constant>&nbsp;</entry>
1131                       <entry>160 kbit/s</entry>
1132                     </row>
1133                     <row>
1134                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_192K</constant>&nbsp;</entry>
1135                       <entry>192 kbit/s</entry>
1136                     </row>
1137                     <row>
1138                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_224K</constant>&nbsp;</entry>
1139                       <entry>224 kbit/s</entry>
1140                     </row>
1141                     <row>
1142                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_256K</constant>&nbsp;</entry>
1143                       <entry>256 kbit/s</entry>
1144                     </row>
1145                     <row>
1146                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_320K</constant>&nbsp;</entry>
1147                       <entry>320 kbit/s</entry>
1148                     </row>
1149                     <row>
1150                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_384K</constant>&nbsp;</entry>
1151                       <entry>384 kbit/s</entry>
1152                     </row>
1153                     <row>
1154                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_448K</constant>&nbsp;</entry>
1155                       <entry>448 kbit/s</entry>
1156                     </row>
1157                     <row>
1158                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_512K</constant>&nbsp;</entry>
1159                       <entry>512 kbit/s</entry>
1160                     </row>
1161                     <row>
1162                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_576K</constant>&nbsp;</entry>
1163                       <entry>576 kbit/s</entry>
1164                     </row>
1165                     <row>
1166                       <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_640K</constant>&nbsp;</entry>
1167                       <entry>640 kbit/s</entry>
1168                     </row>
1169                   </tbody>
1170                 </entrytbl>
1171               </row>
1172               <row><entry></entry></row>
1173               <row id="v4l2-mpeg-audio-mode">
1174                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MODE</constant>&nbsp;</entry>
1175                 <entry>enum&nbsp;v4l2_mpeg_audio_mode</entry>
1176               </row><row><entry spanname="descr">MPEG Audio mode.
1177 Possible values are:</entry>
1178               </row>
1179               <row>
1180                 <entrytbl spanname="descr" cols="2">
1181                   <tbody valign="top">
1182                     <row>
1183                       <entry><constant>V4L2_MPEG_AUDIO_MODE_STEREO</constant>&nbsp;</entry>
1184                       <entry>Stereo</entry>
1185                     </row>
1186                     <row>
1187                       <entry><constant>V4L2_MPEG_AUDIO_MODE_JOINT_STEREO</constant>&nbsp;</entry>
1188                       <entry>Joint Stereo</entry>
1189                     </row>
1190                     <row>
1191                       <entry><constant>V4L2_MPEG_AUDIO_MODE_DUAL</constant>&nbsp;</entry>
1192                       <entry>Bilingual</entry>
1193                     </row>
1194                     <row>
1195                       <entry><constant>V4L2_MPEG_AUDIO_MODE_MONO</constant>&nbsp;</entry>
1196                       <entry>Mono</entry>
1197                     </row>
1198                   </tbody>
1199                 </entrytbl>
1200               </row>
1201               <row><entry></entry></row>
1202               <row id="v4l2-mpeg-audio-mode-extension">
1203                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MODE_EXTENSION</constant>&nbsp;</entry>
1204                 <entry>enum&nbsp;v4l2_mpeg_audio_mode_extension</entry>
1205               </row><row><entry spanname="descr">Joint Stereo
1206 audio mode extension. In Layer I and II they indicate which subbands
1207 are in intensity stereo. All other subbands are coded in stereo. Layer
1208 III is not (yet) supported. Possible values
1209 are:</entry>
1210               </row>
1211               <row>
1212                 <entrytbl spanname="descr" cols="2">
1213                   <tbody valign="top">
1214                     <row>
1215                       <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_4</constant>&nbsp;</entry>
1216                       <entry>Subbands 4-31 in intensity stereo</entry>
1217                     </row>
1218                     <row>
1219                       <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_8</constant>&nbsp;</entry>
1220                       <entry>Subbands 8-31 in intensity stereo</entry>
1221                     </row>
1222                     <row>
1223                       <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_12</constant>&nbsp;</entry>
1224                       <entry>Subbands 12-31 in intensity stereo</entry>
1225                     </row>
1226                     <row>
1227                       <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_16</constant>&nbsp;</entry>
1228                       <entry>Subbands 16-31 in intensity stereo</entry>
1229                     </row>
1230                   </tbody>
1231                 </entrytbl>
1232               </row>
1233               <row><entry></entry></row>
1234               <row id="v4l2-mpeg-audio-emphasis">
1235                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_EMPHASIS</constant>&nbsp;</entry>
1236                 <entry>enum&nbsp;v4l2_mpeg_audio_emphasis</entry>
1237               </row><row><entry spanname="descr">Audio Emphasis.
1238 Possible values are:</entry>
1239               </row>
1240               <row>
1241                 <entrytbl spanname="descr" cols="2">
1242                   <tbody valign="top">
1243                     <row>
1244                       <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_NONE</constant>&nbsp;</entry>
1245                       <entry>None</entry>
1246                     </row>
1247                     <row>
1248                       <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_50_DIV_15_uS</constant>&nbsp;</entry>
1249                       <entry>50/15 microsecond emphasis</entry>
1250                     </row>
1251                     <row>
1252                       <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_CCITT_J17</constant>&nbsp;</entry>
1253                       <entry>CCITT J.17</entry>
1254                     </row>
1255                   </tbody>
1256                 </entrytbl>
1257               </row>
1258               <row><entry></entry></row>
1259               <row id="v4l2-mpeg-audio-crc">
1260                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_CRC</constant>&nbsp;</entry>
1261                 <entry>enum&nbsp;v4l2_mpeg_audio_crc</entry>
1262               </row><row><entry spanname="descr">CRC method. Possible
1263 values are:</entry>
1264               </row>
1265               <row>
1266                 <entrytbl spanname="descr" cols="2">
1267                   <tbody valign="top">
1268                     <row>
1269                       <entry><constant>V4L2_MPEG_AUDIO_CRC_NONE</constant>&nbsp;</entry>
1270                       <entry>None</entry>
1271                     </row>
1272                     <row>
1273                       <entry><constant>V4L2_MPEG_AUDIO_CRC_CRC16</constant>&nbsp;</entry>
1274                       <entry>16 bit parity check</entry>
1275                     </row>
1276                   </tbody>
1277                 </entrytbl>
1278               </row>
1279               <row><entry></entry></row>
1280               <row>
1281                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MUTE</constant>&nbsp;</entry>
1282                 <entry>boolean</entry>
1283               </row><row><entry spanname="descr">Mutes the audio when
1284 capturing. This is not done by muting audio hardware, which can still
1285 produce a slight hiss, but in the encoder itself, guaranteeing a fixed
1286 and reproducible audio bitstream. 0 = unmuted, 1 = muted.</entry>
1287               </row>
1288               <row><entry></entry></row>
1289               <row id="v4l2-mpeg-audio-dec-playback">
1290                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_DEC_PLAYBACK</constant>&nbsp;</entry>
1291                 <entry>enum&nbsp;v4l2_mpeg_audio_dec_playback</entry>
1292               </row><row><entry spanname="descr">Determines how monolingual audio should be played back.
1293 Possible values are:</entry>
1294               </row>
1295               <row>
1296                 <entrytbl spanname="descr" cols="2">
1297                   <tbody valign="top">
1298                     <row>
1299                       <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_AUTO</constant>&nbsp;</entry>
1300                       <entry>Automatically determines the best playback mode.</entry>
1301                     </row>
1302                     <row>
1303                       <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_STEREO</constant>&nbsp;</entry>
1304                       <entry>Stereo playback.</entry>
1305                     </row>
1306                     <row>
1307                       <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_LEFT</constant>&nbsp;</entry>
1308                       <entry>Left channel playback.</entry>
1309                     </row>
1310                     <row>
1311                       <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_RIGHT</constant>&nbsp;</entry>
1312                       <entry>Right channel playback.</entry>
1313                     </row>
1314                     <row>
1315                       <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_MONO</constant>&nbsp;</entry>
1316                       <entry>Mono playback.</entry>
1317                     </row>
1318                     <row>
1319                       <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_SWAPPED_STEREO</constant>&nbsp;</entry>
1320                       <entry>Stereo playback with swapped left and right channels.</entry>
1321                     </row>
1322                   </tbody>
1323                 </entrytbl>
1324               </row>
1325               <row><entry></entry></row>
1326               <row id="v4l2-mpeg-audio-dec-multilingual-playback">
1327                 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_DEC_MULTILINGUAL_PLAYBACK</constant>&nbsp;</entry>
1328                 <entry>enum&nbsp;v4l2_mpeg_audio_dec_playback</entry>
1329               </row><row><entry spanname="descr">Determines how multilingual audio should be played back.</entry>
1330               </row>
1331               <row><entry></entry></row>
1332               <row id="v4l2-mpeg-video-encoding">
1333                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_ENCODING</constant>&nbsp;</entry>
1334                 <entry>enum&nbsp;v4l2_mpeg_video_encoding</entry>
1335               </row><row><entry spanname="descr">MPEG Video encoding
1336 method. This control is specific to multiplexed MPEG streams.
1337 Possible values are:</entry>
1338               </row>
1339               <row>
1340                 <entrytbl spanname="descr" cols="2">
1341                   <tbody valign="top">
1342                     <row>
1343                       <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_1</constant>&nbsp;</entry>
1344                       <entry>MPEG-1 Video encoding</entry>
1345                     </row>
1346                     <row>
1347                       <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_2</constant>&nbsp;</entry>
1348                       <entry>MPEG-2 Video encoding</entry>
1349                     </row>
1350                     <row>
1351                       <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC</constant>&nbsp;</entry>
1352                       <entry>MPEG-4 AVC (H.264) Video encoding</entry>
1353                     </row>
1354                   </tbody>
1355                 </entrytbl>
1356               </row>
1357               <row><entry></entry></row>
1358               <row id="v4l2-mpeg-video-aspect">
1359                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_ASPECT</constant>&nbsp;</entry>
1360                 <entry>enum&nbsp;v4l2_mpeg_video_aspect</entry>
1361               </row><row><entry spanname="descr">Video aspect.
1362 Possible values are:</entry>
1363               </row>
1364               <row>
1365                 <entrytbl spanname="descr" cols="2">
1366                   <tbody valign="top">
1367                     <row>
1368                       <entry><constant>V4L2_MPEG_VIDEO_ASPECT_1x1</constant>&nbsp;</entry>
1369                     </row>
1370                     <row>
1371                       <entry><constant>V4L2_MPEG_VIDEO_ASPECT_4x3</constant>&nbsp;</entry>
1372                     </row>
1373                     <row>
1374                       <entry><constant>V4L2_MPEG_VIDEO_ASPECT_16x9</constant>&nbsp;</entry>
1375                     </row>
1376                     <row>
1377                       <entry><constant>V4L2_MPEG_VIDEO_ASPECT_221x100</constant>&nbsp;</entry>
1378                     </row>
1379                   </tbody>
1380                 </entrytbl>
1381               </row>
1382               <row><entry></entry></row>
1383               <row>
1384                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_B_FRAMES</constant>&nbsp;</entry>
1385                 <entry>integer</entry>
1386               </row><row><entry spanname="descr">Number of B-Frames
1387 (default 2)</entry>
1388               </row>
1389               <row><entry></entry></row>
1390               <row>
1391                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_GOP_SIZE</constant>&nbsp;</entry>
1392                 <entry>integer</entry>
1393               </row><row><entry spanname="descr">GOP size (default
1394 12)</entry>
1395               </row>
1396               <row><entry></entry></row>
1397               <row>
1398                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_GOP_CLOSURE</constant>&nbsp;</entry>
1399                 <entry>boolean</entry>
1400               </row><row><entry spanname="descr">GOP closure (default
1401 1)</entry>
1402               </row>
1403               <row><entry></entry></row>
1404               <row>
1405                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_PULLDOWN</constant>&nbsp;</entry>
1406                 <entry>boolean</entry>
1407               </row><row><entry spanname="descr">Enable 3:2 pulldown
1408 (default 0)</entry>
1409               </row>
1410               <row><entry></entry></row>
1411               <row id="v4l2-mpeg-video-bitrate-mode">
1412                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE_MODE</constant>&nbsp;</entry>
1413                 <entry>enum&nbsp;v4l2_mpeg_video_bitrate_mode</entry>
1414               </row><row><entry spanname="descr">Video bitrate mode.
1415 Possible values are:</entry>
1416               </row>
1417               <row>
1418                 <entrytbl spanname="descr" cols="2">
1419                   <tbody valign="top">
1420                     <row>
1421                       <entry><constant>V4L2_MPEG_VIDEO_BITRATE_MODE_VBR</constant>&nbsp;</entry>
1422                       <entry>Variable bitrate</entry>
1423                     </row>
1424                     <row>
1425                       <entry><constant>V4L2_MPEG_VIDEO_BITRATE_MODE_CBR</constant>&nbsp;</entry>
1426                       <entry>Constant bitrate</entry>
1427                     </row>
1428                   </tbody>
1429                 </entrytbl>
1430               </row>
1431               <row><entry></entry></row>
1432               <row>
1433                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE</constant>&nbsp;</entry>
1434                 <entry>integer</entry>
1435               </row><row><entry spanname="descr">Video bitrate in bits
1436 per second.</entry>
1437               </row>
1438               <row><entry></entry></row>
1439               <row>
1440                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE_PEAK</constant>&nbsp;</entry>
1441                 <entry>integer</entry>
1442               </row><row><entry spanname="descr">Peak video bitrate in
1443 bits per second. Must be larger or equal to the average video bitrate.
1444 It is ignored if the video bitrate mode is set to constant
1445 bitrate.</entry>
1446               </row>
1447               <row><entry></entry></row>
1448               <row>
1449                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION</constant>&nbsp;</entry>
1450                 <entry>integer</entry>
1451               </row><row><entry spanname="descr">For every captured
1452 frame, skip this many subsequent frames (default 0).</entry>
1453               </row>
1454               <row><entry></entry></row>
1455               <row>
1456                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MUTE</constant>&nbsp;</entry>
1457                 <entry>boolean</entry>
1458               </row>
1459               <row><entry spanname="descr">"Mutes" the video to a
1460 fixed color when capturing. This is useful for testing, to produce a
1461 fixed video bitstream. 0 = unmuted, 1 = muted.</entry>
1462               </row>
1463               <row><entry></entry></row>
1464               <row>
1465                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MUTE_YUV</constant>&nbsp;</entry>
1466                 <entry>integer</entry>
1467               </row><row><entry spanname="descr">Sets the "mute" color
1468 of the video. The supplied 32-bit integer is interpreted as follows (bit
1469 0 = least significant bit):</entry>
1470               </row>
1471               <row>
1472                 <entrytbl spanname="descr" cols="2">
1473                   <tbody valign="top">
1474                     <row>
1475                       <entry>Bit 0:7</entry>
1476                       <entry>V chrominance information</entry>
1477                     </row>
1478                     <row>
1479                       <entry>Bit 8:15</entry>
1480                       <entry>U chrominance information</entry>
1481                     </row>
1482                     <row>
1483                       <entry>Bit 16:23</entry>
1484                       <entry>Y luminance information</entry>
1485                     </row>
1486                     <row>
1487                       <entry>Bit 24:31</entry>
1488                       <entry>Must be zero.</entry>
1489                     </row>
1490                   </tbody>
1491                 </entrytbl>
1492               </row>
1493               <row><entry></entry></row>
1494               <row id="v4l2-mpeg-video-dec-pts">
1495                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DEC_PTS</constant>&nbsp;</entry>
1496                 <entry>integer64</entry>
1497               </row><row><entry spanname="descr">This read-only control returns the
1498 33-bit video Presentation Time Stamp as defined in ITU T-REC-H.222.0 and ISO/IEC 13818-1 of
1499 the currently displayed frame. This is the same PTS as is used in &VIDIOC-DECODER-CMD;.</entry>
1500               </row>
1501               <row><entry></entry></row>
1502               <row id="v4l2-mpeg-video-dec-frame">
1503                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DEC_FRAME</constant>&nbsp;</entry>
1504                 <entry>integer64</entry>
1505               </row><row><entry spanname="descr">This read-only control returns the
1506 frame counter of the frame that is currently displayed (decoded). This value is reset to 0 whenever
1507 the decoder is started.</entry>
1508               </row>
1509
1510
1511               <row><entry></entry></row>
1512               <row>
1513                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DECODER_SLICE_INTERFACE</constant>&nbsp;</entry>
1514                 <entry>boolean</entry>
1515               </row>
1516               <row><entry spanname="descr">If enabled the decoder expects to receive a single slice per buffer, otherwise
1517 the decoder expects a single frame in per buffer. Applicable to the decoder, all codecs.
1518 </entry>
1519               </row>
1520
1521               <row><entry></entry></row>
1522               <row>
1523                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_ENABLE</constant>&nbsp;</entry>
1524                 <entry>boolean</entry>
1525               </row>
1526               <row><entry spanname="descr">Enable writing sample aspect ratio in the Video Usability Information.
1527 Applicable to the H264 encoder.</entry>
1528               </row>
1529
1530               <row><entry></entry></row>
1531               <row id="v4l2-mpeg-video-h264-vui-sar-idc">
1532                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC</constant>&nbsp;</entry>
1533                 <entry>enum&nbsp;v4l2_mpeg_video_h264_vui_sar_idc</entry>
1534               </row>
1535               <row><entry spanname="descr">VUI sample aspect ratio indicator for H.264 encoding. The value
1536 is defined in the table E-1 in the standard. Applicable to the H264 encoder.</entry>
1537               </row>
1538               <row>
1539                 <entrytbl spanname="descr" cols="2">
1540                   <tbody valign="top">
1541
1542                         <row>
1543                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_UNSPECIFIED</constant>&nbsp;</entry>
1544                           <entry>Unspecified</entry>
1545                         </row>
1546                         <row>
1547                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_1x1</constant>&nbsp;</entry>
1548                           <entry>1x1</entry>
1549                         </row>
1550                         <row>
1551                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_12x11</constant>&nbsp;</entry>
1552                           <entry>12x11</entry>
1553                         </row>
1554                         <row>
1555                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_10x11</constant>&nbsp;</entry>
1556                           <entry>10x11</entry>
1557                         </row>
1558                         <row>
1559                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_16x11</constant>&nbsp;</entry>
1560                           <entry>16x11</entry>
1561                         </row>
1562                         <row>
1563                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_40x33</constant>&nbsp;</entry>
1564                           <entry>40x33</entry>
1565                         </row>
1566                         <row>
1567                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_24x11</constant>&nbsp;</entry>
1568                           <entry>24x11</entry>
1569                         </row>
1570                         <row>
1571                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_20x11</constant>&nbsp;</entry>
1572                           <entry>20x11</entry>
1573                         </row>
1574                         <row>
1575                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_32x11</constant>&nbsp;</entry>
1576                           <entry>32x11</entry>
1577                         </row>
1578                         <row>
1579                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_80x33</constant>&nbsp;</entry>
1580                           <entry>80x33</entry>
1581                         </row>
1582                         <row>
1583                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_18x11</constant>&nbsp;</entry>
1584                           <entry>18x11</entry>
1585                         </row>
1586                         <row>
1587                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_15x11</constant>&nbsp;</entry>
1588                           <entry>15x11</entry>
1589                         </row>
1590                         <row>
1591                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_64x33</constant>&nbsp;</entry>
1592                           <entry>64x33</entry>
1593                         </row>
1594                         <row>
1595                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_160x99</constant>&nbsp;</entry>
1596                           <entry>160x99</entry>
1597                         </row>
1598                         <row>
1599                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_4x3</constant>&nbsp;</entry>
1600                           <entry>4x3</entry>
1601                         </row>
1602                         <row>
1603                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_3x2</constant>&nbsp;</entry>
1604                           <entry>3x2</entry>
1605                         </row>
1606                         <row>
1607                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_2x1</constant>&nbsp;</entry>
1608                           <entry>2x1</entry>
1609                         </row>
1610                         <row>
1611                           <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_EXTENDED</constant>&nbsp;</entry>
1612                           <entry>Extended SAR</entry>
1613                         </row>
1614                   </tbody>
1615                 </entrytbl>
1616               </row>
1617
1618               <row><entry></entry></row>
1619               <row>
1620                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_EXT_SAR_WIDTH</constant>&nbsp;</entry>
1621                 <entry>integer</entry>
1622               </row>
1623               <row><entry spanname="descr">Extended sample aspect ratio width for H.264 VUI encoding.
1624 Applicable to the H264 encoder.</entry>
1625               </row>
1626
1627               <row><entry></entry></row>
1628               <row>
1629                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_EXT_SAR_HEIGHT</constant>&nbsp;</entry>
1630                 <entry>integer</entry>
1631               </row>
1632               <row><entry spanname="descr">Extended sample aspect ratio height for H.264 VUI encoding.
1633 Applicable to the H264 encoder.</entry>
1634               </row>
1635
1636               <row><entry></entry></row>
1637               <row id="v4l2-mpeg-video-h264-level">
1638                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LEVEL</constant>&nbsp;</entry>
1639                 <entry>enum&nbsp;v4l2_mpeg_video_h264_level</entry>
1640               </row>
1641               <row><entry spanname="descr">The level information for the H264 video elementary stream.
1642 Applicable to the H264 encoder.
1643 Possible values are:</entry>
1644               </row>
1645               <row>
1646                 <entrytbl spanname="descr" cols="2">
1647                   <tbody valign="top">
1648                     <row>
1649                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1_0</constant>&nbsp;</entry>
1650                       <entry>Level 1.0</entry>
1651                     </row>
1652                     <row>
1653                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1B</constant>&nbsp;</entry>
1654                       <entry>Level 1B</entry>
1655                     </row>
1656                     <row>
1657                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1_1</constant>&nbsp;</entry>
1658                       <entry>Level 1.1</entry>
1659                     </row>
1660                     <row>
1661                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1_2</constant>&nbsp;</entry>
1662                       <entry>Level 1.2</entry>
1663                     </row>
1664                     <row>
1665                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1_3</constant>&nbsp;</entry>
1666                       <entry>Level 1.3</entry>
1667                     </row>
1668                     <row>
1669                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_2_0</constant>&nbsp;</entry>
1670                       <entry>Level 2.0</entry>
1671                     </row>
1672                     <row>
1673                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_2_1</constant>&nbsp;</entry>
1674                       <entry>Level 2.1</entry>
1675                     </row>
1676                     <row>
1677                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_2_2</constant>&nbsp;</entry>
1678                       <entry>Level 2.2</entry>
1679                     </row>
1680                     <row>
1681                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_3_0</constant>&nbsp;</entry>
1682                       <entry>Level 3.0</entry>
1683                     </row>
1684                     <row>
1685                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_3_1</constant>&nbsp;</entry>
1686                       <entry>Level 3.1</entry>
1687                     </row>
1688                     <row>
1689                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_3_2</constant>&nbsp;</entry>
1690                       <entry>Level 3.2</entry>
1691                     </row>
1692                     <row>
1693                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_4_0</constant>&nbsp;</entry>
1694                       <entry>Level 4.0</entry>
1695                     </row>
1696                     <row>
1697                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_4_1</constant>&nbsp;</entry>
1698                       <entry>Level 4.1</entry>
1699                     </row>
1700                     <row>
1701                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_4_2</constant>&nbsp;</entry>
1702                       <entry>Level 4.2</entry>
1703                     </row>
1704                     <row>
1705                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_5_0</constant>&nbsp;</entry>
1706                       <entry>Level 5.0</entry>
1707                     </row>
1708                     <row>
1709                       <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_5_1</constant>&nbsp;</entry>
1710                       <entry>Level 5.1</entry>
1711                     </row>
1712                   </tbody>
1713                 </entrytbl>
1714               </row>
1715
1716               <row><entry></entry></row>
1717               <row id="v4l2-mpeg-video-mpeg4-level">
1718                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL</constant>&nbsp;</entry>
1719                 <entry>enum&nbsp;v4l2_mpeg_video_mpeg4_level</entry>
1720               </row>
1721               <row><entry spanname="descr">The level information for the MPEG4 elementary stream.
1722 Applicable to the MPEG4 encoder.
1723 Possible values are:</entry>
1724               </row>
1725               <row>
1726                 <entrytbl spanname="descr" cols="2">
1727                   <tbody valign="top">
1728                     <row>
1729                       <entry><constant>V4L2_MPEG_VIDEO_LEVEL_0</constant>&nbsp;</entry>
1730                       <entry>Level 0</entry>
1731                     </row>
1732                     <row>
1733                       <entry><constant>V4L2_MPEG_VIDEO_LEVEL_0B</constant>&nbsp;</entry>
1734                       <entry>Level 0b</entry>
1735                     </row>
1736                     <row>
1737                       <entry><constant>V4L2_MPEG_VIDEO_LEVEL_1</constant>&nbsp;</entry>
1738                       <entry>Level 1</entry>
1739                     </row>
1740                     <row>
1741                       <entry><constant>V4L2_MPEG_VIDEO_LEVEL_2</constant>&nbsp;</entry>
1742                       <entry>Level 2</entry>
1743                     </row>
1744                     <row>
1745                       <entry><constant>V4L2_MPEG_VIDEO_LEVEL_3</constant>&nbsp;</entry>
1746                       <entry>Level 3</entry>
1747                     </row>
1748                     <row>
1749                       <entry><constant>V4L2_MPEG_VIDEO_LEVEL_3B</constant>&nbsp;</entry>
1750                       <entry>Level 3b</entry>
1751                     </row>
1752                     <row>
1753                       <entry><constant>V4L2_MPEG_VIDEO_LEVEL_4</constant>&nbsp;</entry>
1754                       <entry>Level 4</entry>
1755                     </row>
1756                     <row>
1757                       <entry><constant>V4L2_MPEG_VIDEO_LEVEL_5</constant>&nbsp;</entry>
1758                       <entry>Level 5</entry>
1759                     </row>
1760                   </tbody>
1761                 </entrytbl>
1762               </row>
1763
1764               <row><entry></entry></row>
1765               <row id="v4l2-mpeg-video-h264-profile">
1766                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_PROFILE</constant>&nbsp;</entry>
1767                 <entry>enum&nbsp;v4l2_mpeg_video_h264_profile</entry>
1768               </row>
1769               <row><entry spanname="descr">The profile information for H264.
1770 Applicable to the H264 encoder.
1771 Possible values are:</entry>
1772               </row>
1773               <row>
1774                 <entrytbl spanname="descr" cols="2">
1775                   <tbody valign="top">
1776                     <row>
1777                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_BASELINE</constant>&nbsp;</entry>
1778                       <entry>Baseline profile</entry>
1779                     </row>
1780                     <row>
1781                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_CONSTRAINED_BASELINE</constant>&nbsp;</entry>
1782                       <entry>Constrained Baseline profile</entry>
1783                     </row>
1784                     <row>
1785                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_MAIN</constant>&nbsp;</entry>
1786                       <entry>Main profile</entry>
1787                     </row>
1788                     <row>
1789                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_EXTENDED</constant>&nbsp;</entry>
1790                       <entry>Extended profile</entry>
1791                     </row>
1792                     <row>
1793                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH</constant>&nbsp;</entry>
1794                       <entry>High profile</entry>
1795                     </row>
1796                     <row>
1797                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_10</constant>&nbsp;</entry>
1798                       <entry>High 10 profile</entry>
1799                     </row>
1800                     <row>
1801                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_422</constant>&nbsp;</entry>
1802                       <entry>High 422 profile</entry>
1803                     </row>
1804                     <row>
1805                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_444_PREDICTIVE</constant>&nbsp;</entry>
1806                       <entry>High 444 Predictive profile</entry>
1807                     </row>
1808                     <row>
1809                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_10_INTRA</constant>&nbsp;</entry>
1810                       <entry>High 10 Intra profile</entry>
1811                     </row>
1812                     <row>
1813                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_422_INTRA</constant>&nbsp;</entry>
1814                       <entry>High 422 Intra profile</entry>
1815                     </row>
1816                     <row>
1817                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_444_INTRA</constant>&nbsp;</entry>
1818                       <entry>High 444 Intra profile</entry>
1819                     </row>
1820                     <row>
1821                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_CAVLC_444_INTRA</constant>&nbsp;</entry>
1822                       <entry>CAVLC 444 Intra profile</entry>
1823                     </row>
1824                     <row>
1825                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_BASELINE</constant>&nbsp;</entry>
1826                       <entry>Scalable Baseline profile</entry>
1827                     </row>
1828                     <row>
1829                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_HIGH</constant>&nbsp;</entry>
1830                       <entry>Scalable High profile</entry>
1831                     </row>
1832                     <row>
1833                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_HIGH_INTRA</constant>&nbsp;</entry>
1834                       <entry>Scalable High Intra profile</entry>
1835                     </row>
1836                     <row>
1837                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_STEREO_HIGH</constant>&nbsp;</entry>
1838                       <entry>Stereo High profile</entry>
1839                     </row>
1840                     <row>
1841                       <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_MULTIVIEW_HIGH</constant>&nbsp;</entry>
1842                       <entry>Multiview High profile</entry>
1843                     </row>
1844
1845                   </tbody>
1846                 </entrytbl>
1847               </row>
1848
1849               <row><entry></entry></row>
1850               <row id="v4l2-mpeg-video-mpeg4-profile">
1851                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_PROFILE</constant>&nbsp;</entry>
1852                 <entry>enum&nbsp;v4l2_mpeg_video_mpeg4_profile</entry>
1853               </row>
1854               <row><entry spanname="descr">The profile information for MPEG4.
1855 Applicable to the MPEG4 encoder.
1856 Possible values are:</entry>
1857               </row>
1858               <row>
1859                 <entrytbl spanname="descr" cols="2">
1860                   <tbody valign="top">
1861                     <row>
1862                       <entry><constant>V4L2_MPEG_VIDEO_PROFILE_SIMPLE</constant>&nbsp;</entry>
1863                       <entry>Simple profile</entry>
1864                     </row>
1865                     <row>
1866                       <entry><constant>V4L2_MPEG_VIDEO_PROFILE_ADVANCED_SIMPLE</constant>&nbsp;</entry>
1867                       <entry>Advanced Simple profile</entry>
1868                     </row>
1869                     <row>
1870                       <entry><constant>V4L2_MPEG_VIDEO_PROFILE_CORE</constant>&nbsp;</entry>
1871                       <entry>Core profile</entry>
1872                     </row>
1873                     <row>
1874                       <entry><constant>V4L2_MPEG_VIDEO_PROFILE_SIMPLE_SCALABLE</constant>&nbsp;</entry>
1875                       <entry>Simple Scalable profile</entry>
1876                     </row>
1877                     <row>
1878                       <entry><constant>V4L2_MPEG_VIDEO_PROFILE_ADVANCED_CODING_EFFICIENCY</constant>&nbsp;</entry>
1879                       <entry></entry>
1880                     </row>
1881                   </tbody>
1882                 </entrytbl>
1883               </row>
1884
1885               <row><entry></entry></row>
1886               <row>
1887                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MAX_REF_PIC</constant>&nbsp;</entry>
1888                 <entry>integer</entry>
1889               </row>
1890               <row><entry spanname="descr">The maximum number of reference pictures used for encoding.
1891 Applicable to the encoder.
1892 </entry>
1893               </row>
1894
1895               <row><entry></entry></row>
1896               <row id="v4l2-mpeg-video-multi-slice-mode">
1897                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE</constant>&nbsp;</entry>
1898                 <entry>enum&nbsp;v4l2_mpeg_video_multi_slice_mode</entry>
1899               </row>
1900               <row><entry spanname="descr">Determines how the encoder should handle division of frame into slices.
1901 Applicable to the encoder.
1902 Possible values are:</entry>
1903               </row>
1904               <row>
1905                 <entrytbl spanname="descr" cols="2">
1906                   <tbody valign="top">
1907                     <row>
1908                       <entry><constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_SINGLE</constant>&nbsp;</entry>
1909                       <entry>Single slice per frame.</entry>
1910                     </row>
1911                     <row>
1912                       <entry><constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB</constant>&nbsp;</entry>
1913                       <entry>Multiple slices with set maximum number of macroblocks per slice.</entry>
1914                     </row>
1915                     <row>
1916                       <entry><constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_BYTES</constant>&nbsp;</entry>
1917                       <entry>Multiple slice with set maximum size in bytes per slice.</entry>
1918                     </row>
1919                   </tbody>
1920                 </entrytbl>
1921               </row>
1922
1923               <row><entry></entry></row>
1924               <row>
1925                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_MB</constant>&nbsp;</entry>
1926                 <entry>integer</entry>
1927               </row>
1928               <row><entry spanname="descr">The maximum number of macroblocks in a slice. Used when
1929 <constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE</constant> is set to <constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB</constant>.
1930 Applicable to the encoder.</entry>
1931               </row>
1932
1933               <row><entry></entry></row>
1934               <row>
1935                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_BYTES</constant>&nbsp;</entry>
1936                 <entry>integer</entry>
1937               </row>
1938               <row><entry spanname="descr">The maximum size of a slice in bytes. Used when
1939 <constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE</constant> is set to <constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_BYTES</constant>.
1940 Applicable to the encoder.</entry>
1941               </row>
1942
1943               <row><entry></entry></row>
1944               <row id="v4l2-mpeg-video-h264-loop-filter-mode">
1945                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_MODE</constant>&nbsp;</entry>
1946                 <entry>enum&nbsp;v4l2_mpeg_video_h264_loop_filter_mode</entry>
1947               </row>
1948               <row><entry spanname="descr">Loop filter mode for H264 encoder.
1949 Possible values are:</entry>
1950               </row>
1951               <row>
1952                 <entrytbl spanname="descr" cols="2">
1953                   <tbody valign="top">
1954                     <row>
1955                       <entry><constant>V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_ENABLED</constant>&nbsp;</entry>
1956                       <entry>Loop filter is enabled.</entry>
1957                     </row>
1958                     <row>
1959                       <entry><constant>V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_DISABLED</constant>&nbsp;</entry>
1960                       <entry>Loop filter is disabled.</entry>
1961                     </row>
1962                     <row>
1963                       <entry><constant>V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_DISABLED_AT_SLICE_BOUNDARY</constant>&nbsp;</entry>
1964                       <entry>Loop filter is disabled at the slice boundary.</entry>
1965                     </row>
1966                   </tbody>
1967                 </entrytbl>
1968               </row>
1969
1970               <row><entry></entry></row>
1971               <row>
1972                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_ALPHA</constant>&nbsp;</entry>
1973                 <entry>integer</entry>
1974               </row>
1975               <row><entry spanname="descr">Loop filter alpha coefficient, defined in the H264 standard.
1976 Applicable to the H264 encoder.</entry>
1977               </row>
1978
1979               <row><entry></entry></row>
1980               <row>
1981                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_BETA</constant>&nbsp;</entry>
1982                 <entry>integer</entry>
1983               </row>
1984               <row><entry spanname="descr">Loop filter beta coefficient, defined in the H264 standard.
1985 Applicable to the H264 encoder.</entry>
1986               </row>
1987
1988               <row><entry></entry></row>
1989               <row id="v4l2-mpeg-video-h264-entropy-mode">
1990                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_ENTROPY_MODE</constant>&nbsp;</entry>
1991                 <entry>enum&nbsp;v4l2_mpeg_video_h264_entropy_mode</entry>
1992               </row>
1993               <row><entry spanname="descr">Entropy coding mode for H264 - CABAC/CAVALC.
1994 Applicable to the H264 encoder.
1995 Possible values are:</entry>
1996               </row>
1997               <row>
1998                 <entrytbl spanname="descr" cols="2">
1999                   <tbody valign="top">
2000                     <row>
2001                       <entry><constant>V4L2_MPEG_VIDEO_H264_ENTROPY_MODE_CAVLC</constant>&nbsp;</entry>
2002                       <entry>Use CAVLC entropy coding.</entry>
2003                     </row>
2004                     <row>
2005                       <entry><constant>V4L2_MPEG_VIDEO_H264_ENTROPY_MODE_CABAC</constant>&nbsp;</entry>
2006                       <entry>Use CABAC entropy coding.</entry>
2007                     </row>
2008                   </tbody>
2009                 </entrytbl>
2010               </row>
2011
2012               <row><entry></entry></row>
2013               <row>
2014                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_8X8_TRANSFORM</constant>&nbsp;</entry>
2015                 <entry>boolean</entry>
2016               </row>
2017               <row><entry spanname="descr">Enable 8X8 transform for H264. Applicable to the H264 encoder.</entry>
2018               </row>
2019
2020               <row><entry></entry></row>
2021               <row>
2022                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_CYCLIC_INTRA_REFRESH_MB</constant>&nbsp;</entry>
2023                 <entry>integer</entry>
2024               </row>
2025               <row><entry spanname="descr">Cyclic intra macroblock refresh. This is the number of continuous macroblocks
2026 refreshed every frame. Each frame a succesive set of macroblocks is refreshed until the cycle completes and starts from the
2027 top of the frame. Applicable to H264, H263 and MPEG4 encoder.</entry>
2028               </row>
2029
2030               <row><entry></entry></row>
2031               <row>
2032                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE</constant>&nbsp;</entry>
2033                 <entry>boolean</entry>
2034               </row>
2035               <row><entry spanname="descr">Frame level rate control enable.
2036 If this control is disabled then the quantization parameter for each frame type is constant and set with appropriate controls
2037 (e.g. <constant>V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP</constant>).
2038 If frame rate control is enabled then quantization parameter is adjusted to meet the chosen bitrate. Minimum and maximum value
2039 for the quantization parameter can be set with appropriate controls (e.g. <constant>V4L2_CID_MPEG_VIDEO_H263_MIN_QP</constant>).
2040 Applicable to encoders.</entry>
2041               </row>
2042
2043               <row><entry></entry></row>
2044               <row>
2045                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>&nbsp;</entry>
2046                 <entry>boolean</entry>
2047               </row>
2048               <row><entry spanname="descr">Macroblock level rate control enable.
2049 Applicable to the MPEG4 and H264 encoders.</entry>
2050               </row>
2051
2052               <row><entry></entry></row>
2053               <row>
2054                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_QPEL</constant>&nbsp;</entry>
2055                 <entry>boolean</entry>
2056               </row>
2057               <row><entry spanname="descr">Quarter pixel motion estimation for MPEG4. Applicable to the MPEG4 encoder.</entry>
2058               </row>
2059
2060               <row><entry></entry></row>
2061               <row>
2062                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP</constant>&nbsp;</entry>
2063                 <entry>integer</entry>
2064               </row>
2065               <row><entry spanname="descr">Quantization parameter for an I frame for H263. Valid range: from 1 to 31.</entry>
2066               </row>
2067
2068               <row><entry></entry></row>
2069               <row>
2070                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_MIN_QP</constant>&nbsp;</entry>
2071                 <entry>integer</entry>
2072               </row>
2073               <row><entry spanname="descr">Minimum quantization parameter for H263. Valid range: from 1 to 31.</entry>
2074               </row>
2075
2076               <row><entry></entry></row>
2077               <row>
2078                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_MAX_QP</constant>&nbsp;</entry>
2079                 <entry>integer</entry>
2080               </row>
2081               <row><entry spanname="descr">Maximum quantization parameter for H263. Valid range: from 1 to 31.</entry>
2082               </row>
2083
2084               <row><entry></entry></row>
2085               <row>
2086                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_P_FRAME_QP</constant>&nbsp;</entry>
2087                 <entry>integer</entry>
2088               </row>
2089               <row><entry spanname="descr">Quantization parameter for an P frame for H263. Valid range: from 1 to 31.</entry>
2090               </row>
2091
2092               <row><entry></entry></row>
2093               <row>
2094                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_B_FRAME_QP</constant>&nbsp;</entry>
2095                 <entry>integer</entry>
2096               </row>
2097               <row><entry spanname="descr">Quantization parameter for an B frame for H263. Valid range: from 1 to 31.</entry>
2098               </row>
2099
2100               <row><entry></entry></row>
2101               <row>
2102                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_I_FRAME_QP</constant>&nbsp;</entry>
2103                 <entry>integer</entry>
2104               </row>
2105               <row><entry spanname="descr">Quantization parameter for an I frame for H264. Valid range: from 0 to 51.</entry>
2106               </row>
2107
2108               <row><entry></entry></row>
2109               <row>
2110                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_MIN_QP</constant>&nbsp;</entry>
2111                 <entry>integer</entry>
2112               </row>
2113               <row><entry spanname="descr">Minimum quantization parameter for H264. Valid range: from 0 to 51.</entry>
2114               </row>
2115
2116               <row><entry></entry></row>
2117               <row>
2118                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_MAX_QP</constant>&nbsp;</entry>
2119                 <entry>integer</entry>
2120               </row>
2121               <row><entry spanname="descr">Maximum quantization parameter for H264. Valid range: from 0 to 51.</entry>
2122               </row>
2123
2124               <row><entry></entry></row>
2125               <row>
2126                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_P_FRAME_QP</constant>&nbsp;</entry>
2127                 <entry>integer</entry>
2128               </row>
2129               <row><entry spanname="descr">Quantization parameter for an P frame for H264. Valid range: from 0 to 51.</entry>
2130               </row>
2131
2132               <row><entry></entry></row>
2133               <row>
2134                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_B_FRAME_QP</constant>&nbsp;</entry>
2135                 <entry>integer</entry>
2136               </row>
2137               <row><entry spanname="descr">Quantization parameter for an B frame for H264. Valid range: from 0 to 51.</entry>
2138               </row>
2139
2140               <row><entry></entry></row>
2141               <row>
2142                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP</constant>&nbsp;</entry>
2143                 <entry>integer</entry>
2144               </row>
2145               <row><entry spanname="descr">Quantization parameter for an I frame for MPEG4. Valid range: from 1 to 31.</entry>
2146               </row>
2147
2148               <row><entry></entry></row>
2149               <row>
2150                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_MIN_QP</constant>&nbsp;</entry>
2151                 <entry>integer</entry>
2152               </row>
2153               <row><entry spanname="descr">Minimum quantization parameter for MPEG4. Valid range: from 1 to 31.</entry>
2154               </row>
2155
2156               <row><entry></entry></row>
2157               <row>
2158                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_MAX_QP</constant>&nbsp;</entry>
2159                 <entry>integer</entry>
2160               </row>
2161               <row><entry spanname="descr">Maximum quantization parameter for MPEG4. Valid range: from 1 to 31.</entry>
2162               </row>
2163
2164               <row><entry></entry></row>
2165               <row>
2166                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_P_FRAME_QP</constant>&nbsp;</entry>
2167                 <entry>integer</entry>
2168               </row>
2169               <row><entry spanname="descr">Quantization parameter for an P frame for MPEG4. Valid range: from 1 to 31.</entry>
2170               </row>
2171
2172               <row><entry></entry></row>
2173               <row>
2174                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_B_FRAME_QP</constant>&nbsp;</entry>
2175                 <entry>integer</entry>
2176               </row>
2177               <row><entry spanname="descr">Quantization parameter for an B frame for MPEG4. Valid range: from 1 to 31.</entry>
2178               </row>
2179
2180               <row><entry></entry></row>
2181               <row>
2182                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_VBV_SIZE</constant>&nbsp;</entry>
2183                 <entry>integer</entry>
2184               </row>
2185               <row><entry spanname="descr">The Video Buffer Verifier size in kilobytes, it is used as a limitation of frame skip.
2186 The VBV is defined in the standard as a mean to verify that the produced stream will be succesfully decoded.
2187 The standard describes it as "Part of a hypothetical decoder that is conceptually connected to the
2188 output of the encoder. Its purpose is to provide a constraint on the variability of the data rate that an
2189 encoder or editing process may produce.".
2190 Applicable to the MPEG1, MPEG2, MPEG4 encoders.</entry>
2191               </row>
2192
2193               <row><entry></entry></row>
2194               <row>
2195                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_CPB_SIZE</constant>&nbsp;</entry>
2196                 <entry>integer</entry>
2197               </row>
2198               <row><entry spanname="descr">The Coded Picture Buffer size in kilobytes, it is used as a limitation of frame skip.
2199 The CPB is defined in the H264 standard as a mean to verify that the produced stream will be succesfully decoded.
2200 Applicable to the H264 encoder.</entry>
2201               </row>
2202
2203               <row><entry></entry></row>
2204               <row>
2205                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_I_PERIOD</constant>&nbsp;</entry>
2206                 <entry>integer</entry>
2207               </row>
2208               <row><entry spanname="descr">Period between I-frames in the open GOP for H264. In case of an open GOP
2209 this is the period between two I-frames. The period between IDR (Instantaneous Decoding Refresh) frames is taken from the GOP_SIZE control.
2210 An IDR frame, which stands for Instantaneous Decoding Refresh is an I-frame after which no prior frames are
2211 referenced. This means that a stream can be restarted from an IDR frame without the need to store or decode any
2212 previous frames. Applicable to the H264 encoder.</entry>
2213               </row>
2214
2215               <row><entry></entry></row>
2216               <row id="v4l2-mpeg-video-header-mode">
2217                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_HEADER_MODE</constant>&nbsp;</entry>
2218                 <entry>enum&nbsp;v4l2_mpeg_video_header_mode</entry>
2219               </row>
2220               <row><entry spanname="descr">Determines whether the header is returned as the first buffer or is
2221 it returned together with the first frame. Applicable to encoders.
2222 Possible values are:</entry>
2223               </row>
2224               <row>
2225                 <entrytbl spanname="descr" cols="2">
2226                   <tbody valign="top">
2227                     <row>
2228                       <entry><constant>V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE</constant>&nbsp;</entry>
2229                       <entry>The stream header is returned separately in the first buffer.</entry>
2230                     </row>
2231                     <row>
2232                       <entry><constant>V4L2_MPEG_VIDEO_HEADER_MODE_JOINED_WITH_1ST_FRAME</constant>&nbsp;</entry>
2233                       <entry>The stream header is returned together with the first encoded frame.</entry>
2234                     </row>
2235                   </tbody>
2236                 </entrytbl>
2237               </row>
2238               <row><entry></entry></row>
2239               <row>
2240                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DECODER_MPEG4_DEBLOCK_FILTER</constant>&nbsp;</entry>
2241                 <entry>boolean</entry>
2242               </row><row><entry spanname="descr">Enabled the deblocking post processing filter for MPEG4 decoder.
2243 Applicable to the MPEG4 decoder.</entry>
2244               </row>
2245               <row><entry></entry></row>
2246               <row>
2247                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_VOP_TIME_RES</constant>&nbsp;</entry>
2248                 <entry>integer</entry>
2249               </row><row><entry spanname="descr">vop_time_increment_resolution value for MPEG4. Applicable to the MPEG4 encoder.</entry>
2250               </row>
2251               <row><entry></entry></row>
2252               <row>
2253                 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_VOP_TIME_INC</constant>&nbsp;</entry>
2254                 <entry>integer</entry>
2255               </row><row><entry spanname="descr">vop_time_increment value for MPEG4. Applicable to the MPEG4 encoder.</entry>
2256               </row>
2257
2258             </tbody>
2259           </tgroup>
2260         </table>
2261       </section>
2262
2263       <section>
2264         <title>MFC 5.1 MPEG Controls</title>
2265
2266         <para>The following MPEG class controls deal with MPEG
2267 decoding and encoding settings that are specific to the Multi Format Codec 5.1 device present
2268 in the S5P family of SoCs by Samsung.
2269 </para>
2270
2271         <table pgwide="1" frame="none" id="mfc51-control-id">
2272           <title>MFC 5.1 Control IDs</title>
2273           <tgroup cols="4">
2274             <colspec colname="c1" colwidth="1*" />
2275             <colspec colname="c2" colwidth="6*" />
2276             <colspec colname="c3" colwidth="2*" />
2277             <colspec colname="c4" colwidth="6*" />
2278             <spanspec namest="c1" nameend="c2" spanname="id" />
2279             <spanspec namest="c2" nameend="c4" spanname="descr" />
2280             <thead>
2281               <row>
2282                 <entry spanname="id" align="left">ID</entry>
2283                 <entry align="left">Type</entry>
2284               </row><row><entry spanname="descr" align="left">Description</entry>
2285               </row>
2286             </thead>
2287             <tbody valign="top">
2288               <row><entry></entry></row>
2289               <row>
2290                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY_ENABLE</constant>&nbsp;</entry>
2291                 <entry>integer</entry>
2292               </row><row><entry spanname="descr">If the display delay is enabled then the decoder has to return a
2293 CAPTURE buffer after processing a certain number of OUTPUT buffers. If this number is low, then it may result in
2294 buffers not being dequeued in display order. In addition hardware may still use those buffers as reference, thus
2295 application should not write to those buffers. This feature can be used for example for generating thumbnails of videos.
2296 Applicable to the H264 decoder.
2297               </entry>
2298               </row>
2299               <row><entry></entry></row>
2300               <row>
2301                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY</constant>&nbsp;</entry>
2302                 <entry>integer</entry>
2303               </row><row><entry spanname="descr">Display delay value for H264 decoder.
2304 The decoder is forced to return a decoded frame after the set 'display delay' number of frames. If this number is
2305 low it may result in frames returned out of dispaly order, in addition the hardware may still be using the returned buffer
2306 as a reference picture for subsequent frames.
2307 </entry>
2308               </row>
2309               <row><entry></entry></row>
2310               <row>
2311                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P</constant>&nbsp;</entry>
2312                 <entry>integer</entry>
2313               </row><row><entry spanname="descr">The number of reference pictures used for encoding a P picture.
2314 Applicable to the H264 encoder.</entry>
2315               </row>
2316               <row><entry></entry></row>
2317               <row>
2318                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_PADDING</constant>&nbsp;</entry>
2319                 <entry>boolean</entry>
2320               </row><row><entry spanname="descr">Padding enable in the encoder - use a color instead of repeating border pixels.
2321 Applicable to encoders.</entry>
2322               </row>
2323               <row><entry></entry></row>
2324               <row>
2325                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_PADDING_YUV</constant>&nbsp;</entry>
2326                 <entry>integer</entry>
2327               </row><row><entry spanname="descr">Padding color in the encoder. Applicable to encoders. The supplied 32-bit integer is interpreted as follows (bit
2328 0 = least significant bit):</entry>
2329               </row>
2330               <row>
2331                 <entrytbl spanname="descr" cols="2">
2332                   <tbody valign="top">
2333                     <row>
2334                       <entry>Bit 0:7</entry>
2335                       <entry>V chrominance information</entry>
2336                     </row>
2337                     <row>
2338                       <entry>Bit 8:15</entry>
2339                       <entry>U chrominance information</entry>
2340                     </row>
2341                     <row>
2342                       <entry>Bit 16:23</entry>
2343                       <entry>Y luminance information</entry>
2344                     </row>
2345                     <row>
2346                       <entry>Bit 24:31</entry>
2347                       <entry>Must be zero.</entry>
2348                     </row>
2349                   </tbody>
2350                 </entrytbl>
2351               </row>
2352               <row><entry></entry></row>
2353               <row>
2354                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_RC_REACTION_COEFF</constant>&nbsp;</entry>
2355                 <entry>integer</entry>
2356               </row><row><entry spanname="descr">Reaction coefficient for MFC rate control. Applicable to encoders.
2357 <para>Note 1: Valid only when the frame level RC is enabled.</para>
2358 <para>Note 2: For tight CBR, this field must be small (ex. 2 ~ 10).
2359 For VBR, this field must be large (ex. 100 ~ 1000).</para>
2360 <para>Note 3: It is not recommended to use the greater number than FRAME_RATE * (10^9 / BIT_RATE).</para>
2361 </entry>
2362               </row>
2363               <row><entry></entry></row>
2364               <row>
2365                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_DARK</constant>&nbsp;</entry>
2366                 <entry>boolean</entry>
2367               </row><row><entry spanname="descr">Adaptive rate control for dark region.
2368 Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>).
2369 Applicable to the H264 encoder.</entry>
2370               </row>
2371               <row><entry></entry></row>
2372               <row>
2373                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_SMOOTH</constant>&nbsp;</entry>
2374                 <entry>boolean</entry>
2375               </row><row><entry spanname="descr">Adaptive rate control for smooth region.
2376 Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>).
2377 Applicable to the H264 encoder.</entry>
2378               </row>
2379               <row><entry></entry></row>
2380               <row>
2381                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_STATIC</constant>&nbsp;</entry>
2382                 <entry>boolean</entry>
2383               </row><row><entry spanname="descr">Adaptive rate control for static region.
2384 Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>).
2385 Applicable to the H264 encoder.</entry>
2386               </row>
2387               <row><entry></entry></row>
2388               <row>
2389                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_ACTIVITY</constant>&nbsp;</entry>
2390                 <entry>boolean</entry>
2391               </row><row><entry spanname="descr">Adaptive rate control for activity region.
2392 Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>).
2393 Applicable to the H264 encoder.</entry>
2394               </row>
2395               <row><entry></entry></row>
2396               <row id="v4l2-mpeg-mfc51-video-frame-skip-mode">
2397                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_FRAME_SKIP_MODE</constant>&nbsp;</entry>
2398                 <entry>enum&nbsp;v4l2_mpeg_mfc51_video_frame_skip_mode</entry>
2399               </row>
2400               <row><entry spanname="descr">
2401 Indicates in what conditions the encoder should skip frames. If encoding a frame would cause the encoded stream to be larger then
2402 a chosen data limit then the frame will be skipped.
2403 Possible values are:</entry>
2404               </row>
2405               <row>
2406                 <entrytbl spanname="descr" cols="2">
2407                   <tbody valign="top">
2408                     <row>
2409                       <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_DISABLED</constant>&nbsp;</entry>
2410                       <entry>Frame skip mode is disabled.</entry>
2411                     </row>
2412                     <row>
2413                       <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_LEVEL_LIMIT</constant>&nbsp;</entry>
2414                       <entry>Frame skip mode enabled and buffer limit is set by the chosen level and is defined by the standard.</entry>
2415                     </row>
2416                     <row>
2417                       <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_BUF_LIMIT</constant>&nbsp;</entry>
2418                       <entry>Frame skip mode enabled and buffer limit is set by the VBV (MPEG1/2/4) or CPB (H264) buffer size control.</entry>
2419                     </row>
2420                   </tbody>
2421                 </entrytbl>
2422               </row>
2423               <row><entry></entry></row>
2424               <row>
2425                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_RC_FIXED_TARGET_BIT</constant>&nbsp;</entry>
2426                 <entry>integer</entry>
2427               </row><row><entry spanname="descr">Enable rate-control with fixed target bit.
2428 If this setting is enabled, then the rate control logic of the encoder will calculate the average bitrate
2429 for a GOP and keep it below or equal the set bitrate target. Otherwise the rate control logic calculates the
2430 overall average bitrate for the stream and keeps it below or equal to the set bitrate. In the first case
2431 the average bitrate for the whole stream will be smaller then the set bitrate. This is caused because the
2432 average is calculated for smaller number of frames, on the other hand enabling this setting will ensure that
2433 the stream will meet tight bandwidth contraints. Applicable to encoders.
2434 </entry>
2435               </row>
2436               <row><entry></entry></row>
2437               <row id="v4l2-mpeg-mfc51-video-force-frame-type">
2438                 <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE</constant>&nbsp;</entry>
2439                 <entry>enum&nbsp;v4l2_mpeg_mfc51_video_force_frame_type</entry>
2440               </row>
2441               <row><entry spanname="descr">Force a frame type for the next queued buffer. Applicable to encoders.
2442 Possible values are:</entry>
2443               </row>
2444               <row>
2445                 <entrytbl spanname="descr" cols="2">
2446                   <tbody valign="top">
2447                     <row>
2448                       <entry><constant>V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_DISABLED</constant>&nbsp;</entry>
2449                       <entry>Forcing a specific frame type disabled.</entry>
2450                     </row>
2451                     <row>
2452                       <entry><constant>V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_I_FRAME</constant>&nbsp;</entry>
2453                       <entry>Force an I-frame.</entry>
2454                     </row>
2455                     <row>
2456                       <entry><constant>V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_NOT_CODED</constant>&nbsp;</entry>
2457                       <entry>Force a non-coded frame.</entry>
2458                     </row>
2459                   </tbody>
2460                 </entrytbl>
2461               </row>
2462             </tbody>
2463           </tgroup>
2464         </table>
2465       </section>
2466
2467       <section>
2468         <title>CX2341x MPEG Controls</title>
2469
2470         <para>The following MPEG class controls deal with MPEG
2471 encoding settings that are specific to the Conexant CX23415 and
2472 CX23416 MPEG encoding chips.</para>
2473
2474         <table pgwide="1" frame="none" id="cx2341x-control-id">
2475           <title>CX2341x Control IDs</title>
2476           <tgroup cols="4">
2477             <colspec colname="c1" colwidth="1*" />
2478             <colspec colname="c2" colwidth="6*" />
2479             <colspec colname="c3" colwidth="2*" />
2480             <colspec colname="c4" colwidth="6*" />
2481             <spanspec namest="c1" nameend="c2" spanname="id" />
2482             <spanspec namest="c2" nameend="c4" spanname="descr" />
2483             <thead>
2484               <row>
2485                 <entry spanname="id" align="left">ID</entry>
2486                 <entry align="left">Type</entry>
2487               </row><row><entry spanname="descr" align="left">Description</entry>
2488               </row>
2489             </thead>
2490             <tbody valign="top">
2491               <row><entry></entry></row>
2492               <row id="v4l2-mpeg-cx2341x-video-spatial-filter-mode">
2493                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE</constant>&nbsp;</entry>
2494                 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_spatial_filter_mode</entry>
2495               </row><row><entry spanname="descr">Sets the Spatial
2496 Filter mode (default <constant>MANUAL</constant>). Possible values
2497 are:</entry>
2498               </row>
2499               <row>
2500                 <entrytbl spanname="descr" cols="2">
2501                   <tbody valign="top">
2502                     <row>
2503                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_MANUAL</constant>&nbsp;</entry>
2504                       <entry>Choose the filter manually</entry>
2505                     </row>
2506                     <row>
2507                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_AUTO</constant>&nbsp;</entry>
2508                       <entry>Choose the filter automatically</entry>
2509                     </row>
2510                   </tbody>
2511                 </entrytbl>
2512               </row>
2513               <row><entry></entry></row>
2514               <row>
2515                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER</constant>&nbsp;</entry>
2516                 <entry>integer&nbsp;(0-15)</entry>
2517               </row><row><entry spanname="descr">The setting for the
2518 Spatial Filter. 0 = off, 15 = maximum. (Default is 0.)</entry>
2519               </row>
2520               <row><entry></entry></row>
2521               <row id="luma-spatial-filter-type">
2522                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE</constant>&nbsp;</entry>
2523                 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_luma_spatial_filter_type</entry>
2524               </row><row><entry spanname="descr">Select the algorithm
2525 to use for the Luma Spatial Filter (default
2526 <constant>1D_HOR</constant>). Possible values:</entry>
2527               </row>
2528               <row>
2529                 <entrytbl spanname="descr" cols="2">
2530                   <tbody valign="top">
2531                     <row>
2532                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_OFF</constant>&nbsp;</entry>
2533                       <entry>No filter</entry>
2534                     </row>
2535                     <row>
2536                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_HOR</constant>&nbsp;</entry>
2537                       <entry>One-dimensional horizontal</entry>
2538                     </row>
2539                     <row>
2540                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_VERT</constant>&nbsp;</entry>
2541                       <entry>One-dimensional vertical</entry>
2542                     </row>
2543                     <row>
2544                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_HV_SEPARABLE</constant>&nbsp;</entry>
2545                       <entry>Two-dimensional separable</entry>
2546                     </row>
2547                     <row>
2548                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_SYM_NON_SEPARABLE</constant>&nbsp;</entry>
2549                       <entry>Two-dimensional symmetrical
2550 non-separable</entry>
2551                     </row>
2552                   </tbody>
2553                 </entrytbl>
2554               </row>
2555               <row><entry></entry></row>
2556               <row id="chroma-spatial-filter-type">
2557                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE</constant>&nbsp;</entry>
2558                 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_chroma_spatial_filter_type</entry>
2559               </row><row><entry spanname="descr">Select the algorithm
2560 for the Chroma Spatial Filter (default <constant>1D_HOR</constant>).
2561 Possible values are:</entry>
2562               </row>
2563               <row>
2564                 <entrytbl spanname="descr" cols="2">
2565                   <tbody valign="top">
2566                     <row>
2567                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_OFF</constant>&nbsp;</entry>
2568                       <entry>No filter</entry>
2569                     </row>
2570                     <row>
2571                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_1D_HOR</constant>&nbsp;</entry>
2572                       <entry>One-dimensional horizontal</entry>
2573                     </row>
2574                   </tbody>
2575                 </entrytbl>
2576               </row>
2577               <row><entry></entry></row>
2578               <row id="v4l2-mpeg-cx2341x-video-temporal-filter-mode">
2579                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE</constant>&nbsp;</entry>
2580                 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_temporal_filter_mode</entry>
2581               </row><row><entry spanname="descr">Sets the Temporal
2582 Filter mode (default <constant>MANUAL</constant>). Possible values
2583 are:</entry>
2584               </row>
2585               <row>
2586                 <entrytbl spanname="descr" cols="2">
2587                   <tbody valign="top">
2588                     <row>
2589                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_MANUAL</constant>&nbsp;</entry>
2590                       <entry>Choose the filter manually</entry>
2591                     </row>
2592                     <row>
2593                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_AUTO</constant>&nbsp;</entry>
2594                       <entry>Choose the filter automatically</entry>
2595                     </row>
2596                   </tbody>
2597                 </entrytbl>
2598               </row>
2599               <row><entry></entry></row>
2600               <row>
2601                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER</constant>&nbsp;</entry>
2602                 <entry>integer&nbsp;(0-31)</entry>
2603               </row><row><entry spanname="descr">The setting for the
2604 Temporal Filter. 0 = off, 31 = maximum. (Default is 8 for full-scale
2605 capturing and 0 for scaled capturing.)</entry>
2606               </row>
2607               <row><entry></entry></row>
2608               <row id="v4l2-mpeg-cx2341x-video-median-filter-type">
2609                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE</constant>&nbsp;</entry>
2610                 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_median_filter_type</entry>
2611               </row><row><entry spanname="descr">Median Filter Type
2612 (default <constant>OFF</constant>). Possible values are:</entry>
2613               </row>
2614               <row>
2615                 <entrytbl spanname="descr" cols="2">
2616                   <tbody valign="top">
2617                     <row>
2618                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_OFF</constant>&nbsp;</entry>
2619                       <entry>No filter</entry>
2620                     </row>
2621                     <row>
2622                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR</constant>&nbsp;</entry>
2623                       <entry>Horizontal filter</entry>
2624                     </row>
2625                     <row>
2626                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_VERT</constant>&nbsp;</entry>
2627                       <entry>Vertical filter</entry>
2628                     </row>
2629                     <row>
2630                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR_VERT</constant>&nbsp;</entry>
2631                       <entry>Horizontal and vertical filter</entry>
2632                     </row>
2633                     <row>
2634                       <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_DIAG</constant>&nbsp;</entry>
2635                       <entry>Diagonal filter</entry>
2636                     </row>
2637                   </tbody>
2638                 </entrytbl>
2639               </row>
2640               <row><entry></entry></row>
2641               <row>
2642                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_BOTTOM</constant>&nbsp;</entry>
2643                 <entry>integer&nbsp;(0-255)</entry>
2644               </row><row><entry spanname="descr">Threshold above which
2645 the luminance median filter is enabled (default 0)</entry>
2646               </row>
2647               <row><entry></entry></row>
2648               <row>
2649                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_TOP</constant>&nbsp;</entry>
2650                 <entry>integer&nbsp;(0-255)</entry>
2651               </row><row><entry spanname="descr">Threshold below which
2652 the luminance median filter is enabled (default 255)</entry>
2653               </row>
2654               <row><entry></entry></row>
2655               <row>
2656                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_BOTTOM</constant>&nbsp;</entry>
2657                 <entry>integer&nbsp;(0-255)</entry>
2658               </row><row><entry spanname="descr">Threshold above which
2659 the chroma median filter is enabled (default 0)</entry>
2660               </row>
2661               <row><entry></entry></row>
2662               <row>
2663                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_TOP</constant>&nbsp;</entry>
2664                 <entry>integer&nbsp;(0-255)</entry>
2665               </row><row><entry spanname="descr">Threshold below which
2666 the chroma median filter is enabled (default 255)</entry>
2667               </row>
2668               <row><entry></entry></row>
2669               <row>
2670                 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_STREAM_INSERT_NAV_PACKETS</constant>&nbsp;</entry>
2671                 <entry>boolean</entry>
2672               </row>
2673               <row><entry spanname="descr">The CX2341X MPEG encoder
2674 can insert one empty MPEG-2 PES packet into the stream between every
2675 four video frames. The packet size is 2048 bytes, including the
2676 packet_start_code_prefix and stream_id fields. The stream_id is 0xBF
2677 (private stream 2). The payload consists of 0x00 bytes, to be filled
2678 in by the application. 0 = do not insert, 1 = insert packets.</entry>
2679               </row>
2680             </tbody>
2681           </tgroup>
2682         </table>
2683       </section>
2684     </section>
2685
2686     <section id="camera-controls">
2687       <title>Camera Control Reference</title>
2688
2689       <para>The Camera class includes controls for mechanical (or
2690 equivalent digital) features of a device such as controllable lenses
2691 or sensors.</para>
2692
2693     <table pgwide="1" frame="none" id="camera-control-id">
2694       <title>Camera Control IDs</title>
2695       <tgroup cols="4">
2696         <colspec colname="c1" colwidth="1*" />
2697         <colspec colname="c2" colwidth="6*" />
2698         <colspec colname="c3" colwidth="2*" />
2699         <colspec colname="c4" colwidth="6*" />
2700         <spanspec namest="c1" nameend="c2" spanname="id" />
2701         <spanspec namest="c2" nameend="c4" spanname="descr" />
2702         <thead>
2703           <row>
2704             <entry spanname="id" align="left">ID</entry>
2705             <entry align="left">Type</entry>
2706           </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
2707           </row>
2708         </thead>
2709         <tbody valign="top">
2710           <row><entry></entry></row>
2711           <row>
2712             <entry spanname="id"><constant>V4L2_CID_CAMERA_CLASS</constant>&nbsp;</entry>
2713             <entry>class</entry>
2714           </row><row><entry spanname="descr">The Camera class
2715 descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a
2716 description of this control class.</entry>
2717           </row>
2718           <row><entry></entry></row>
2719
2720           <row id="v4l2-exposure-auto-type">
2721             <entry spanname="id"><constant>V4L2_CID_EXPOSURE_AUTO</constant>&nbsp;</entry>
2722             <entry>enum&nbsp;v4l2_exposure_auto_type</entry>
2723           </row><row><entry spanname="descr">Enables automatic
2724 adjustments of the exposure time and/or iris aperture. The effect of
2725 manual changes of the exposure time or iris aperture while these
2726 features are enabled is undefined, drivers should ignore such
2727 requests. Possible values are:</entry>
2728           </row>
2729           <row>
2730             <entrytbl spanname="descr" cols="2">
2731               <tbody valign="top">
2732                 <row>
2733                   <entry><constant>V4L2_EXPOSURE_AUTO</constant>&nbsp;</entry>
2734                       <entry>Automatic exposure time, automatic iris
2735 aperture.</entry>
2736                 </row>
2737                 <row>
2738                   <entry><constant>V4L2_EXPOSURE_MANUAL</constant>&nbsp;</entry>
2739                   <entry>Manual exposure time, manual iris.</entry>
2740                 </row>
2741                 <row>
2742                   <entry><constant>V4L2_EXPOSURE_SHUTTER_PRIORITY</constant>&nbsp;</entry>
2743                   <entry>Manual exposure time, auto iris.</entry>
2744                 </row>
2745                 <row>
2746                   <entry><constant>V4L2_EXPOSURE_APERTURE_PRIORITY</constant>&nbsp;</entry>
2747                   <entry>Auto exposure time, manual iris.</entry>
2748                 </row>
2749               </tbody>
2750             </entrytbl>
2751           </row>
2752           <row><entry></entry></row>
2753
2754           <row>
2755             <entry spanname="id"><constant>V4L2_CID_EXPOSURE_ABSOLUTE</constant>&nbsp;</entry>
2756             <entry>integer</entry>
2757           </row><row><entry spanname="descr">Determines the exposure
2758 time of the camera sensor. The exposure time is limited by the frame
2759 interval. Drivers should interpret the values as 100 &micro;s units,
2760 where the value 1 stands for 1/10000th of a second, 10000 for 1 second
2761 and 100000 for 10 seconds.</entry>
2762           </row>
2763           <row><entry></entry></row>
2764
2765           <row>
2766             <entry spanname="id"><constant>V4L2_CID_EXPOSURE_AUTO_PRIORITY</constant>&nbsp;</entry>
2767             <entry>boolean</entry>
2768           </row><row><entry spanname="descr">When
2769 <constant>V4L2_CID_EXPOSURE_AUTO</constant> is set to
2770 <constant>AUTO</constant> or <constant>APERTURE_PRIORITY</constant>,
2771 this control determines if the device may dynamically vary the frame
2772 rate. By default this feature is disabled (0) and the frame rate must
2773 remain constant.</entry>
2774           </row>
2775           <row><entry></entry></row>
2776
2777           <row>
2778             <entry spanname="id"><constant>V4L2_CID_PAN_RELATIVE</constant>&nbsp;</entry>
2779             <entry>integer</entry>
2780           </row><row><entry spanname="descr">This control turns the
2781 camera horizontally by the specified amount. The unit is undefined. A
2782 positive value moves the camera to the right (clockwise when viewed
2783 from above), a negative value to the left. A value of zero does not
2784 cause motion. This is a write-only control.</entry>
2785           </row>
2786           <row><entry></entry></row>
2787
2788           <row>
2789             <entry spanname="id"><constant>V4L2_CID_TILT_RELATIVE</constant>&nbsp;</entry>
2790             <entry>integer</entry>
2791           </row><row><entry spanname="descr">This control turns the
2792 camera vertically by the specified amount. The unit is undefined. A
2793 positive value moves the camera up, a negative value down. A value of
2794 zero does not cause motion. This is a write-only control.</entry>
2795           </row>
2796           <row><entry></entry></row>
2797
2798           <row>
2799             <entry spanname="id"><constant>V4L2_CID_PAN_RESET</constant>&nbsp;</entry>
2800             <entry>button</entry>
2801           </row><row><entry spanname="descr">When this control is set,
2802 the camera moves horizontally to the default position.</entry>
2803           </row>
2804           <row><entry></entry></row>
2805
2806           <row>
2807             <entry spanname="id"><constant>V4L2_CID_TILT_RESET</constant>&nbsp;</entry>
2808             <entry>button</entry>
2809           </row><row><entry spanname="descr">When this control is set,
2810 the camera moves vertically to the default position.</entry>
2811           </row>
2812           <row><entry></entry></row>
2813
2814           <row>
2815             <entry spanname="id"><constant>V4L2_CID_PAN_ABSOLUTE</constant>&nbsp;</entry>
2816             <entry>integer</entry>
2817           </row><row><entry spanname="descr">This control
2818 turns the camera horizontally to the specified position. Positive
2819 values move the camera to the right (clockwise when viewed from above),
2820 negative values to the left. Drivers should interpret the values as arc
2821 seconds, with valid values between -180 * 3600 and +180 * 3600
2822 inclusive.</entry>
2823           </row>
2824           <row><entry></entry></row>
2825
2826           <row>
2827             <entry spanname="id"><constant>V4L2_CID_TILT_ABSOLUTE</constant>&nbsp;</entry>
2828             <entry>integer</entry>
2829           </row><row><entry spanname="descr">This control
2830 turns the camera vertically to the specified position. Positive values
2831 move the camera up, negative values down. Drivers should interpret the
2832 values as arc seconds, with valid values between -180 * 3600 and +180
2833 * 3600 inclusive.</entry>
2834           </row>
2835           <row><entry></entry></row>
2836
2837           <row>
2838             <entry spanname="id"><constant>V4L2_CID_FOCUS_ABSOLUTE</constant>&nbsp;</entry>
2839             <entry>integer</entry>
2840           </row><row><entry spanname="descr">This control sets the
2841 focal point of the camera to the specified position. The unit is
2842 undefined. Positive values set the focus closer to the camera,
2843 negative values towards infinity.</entry>
2844           </row>
2845           <row><entry></entry></row>
2846
2847           <row>
2848             <entry spanname="id"><constant>V4L2_CID_FOCUS_RELATIVE</constant>&nbsp;</entry>
2849             <entry>integer</entry>
2850           </row><row><entry spanname="descr">This control moves the
2851 focal point of the camera by the specified amount. The unit is
2852 undefined. Positive values move the focus closer to the camera,
2853 negative values towards infinity. This is a write-only control.</entry>
2854           </row>
2855           <row><entry></entry></row>
2856
2857           <row>
2858             <entry spanname="id"><constant>V4L2_CID_FOCUS_AUTO</constant>&nbsp;</entry>
2859             <entry>boolean</entry>
2860           </row><row><entry spanname="descr">Enables automatic focus
2861 adjustments. The effect of manual focus adjustments while this feature
2862 is enabled is undefined, drivers should ignore such requests.</entry>
2863           </row>
2864           <row><entry></entry></row>
2865
2866           <row>
2867             <entry spanname="id"><constant>V4L2_CID_ZOOM_ABSOLUTE</constant>&nbsp;</entry>
2868             <entry>integer</entry>
2869           </row><row><entry spanname="descr">Specify the objective lens
2870 focal length as an absolute value. The zoom unit is driver-specific and its
2871 value should be a positive integer.</entry>
2872           </row>
2873           <row><entry></entry></row>
2874
2875           <row>
2876             <entry spanname="id"><constant>V4L2_CID_ZOOM_RELATIVE</constant>&nbsp;</entry>
2877             <entry>integer</entry>
2878           </row><row><entry spanname="descr">Specify the objective lens
2879 focal length relatively to the current value. Positive values move the zoom
2880 lens group towards the telephoto direction, negative values towards the
2881 wide-angle direction. The zoom unit is driver-specific. This is a write-only control.</entry>
2882           </row>
2883           <row><entry></entry></row>
2884
2885           <row>
2886             <entry spanname="id"><constant>V4L2_CID_ZOOM_CONTINUOUS</constant>&nbsp;</entry>
2887             <entry>integer</entry>
2888           </row><row><entry spanname="descr">Move the objective lens group
2889 at the specified speed until it reaches physical device limits or until an
2890 explicit request to stop the movement. A positive value moves the zoom lens
2891 group towards the telephoto direction. A value of zero stops the zoom lens
2892 group movement. A negative value moves the zoom lens group towards the
2893 wide-angle direction. The zoom speed unit is driver-specific.</entry>
2894           </row>
2895           <row><entry></entry></row>
2896
2897           <row>
2898             <entry spanname="id"><constant>V4L2_CID_IRIS_ABSOLUTE</constant>&nbsp;</entry>
2899             <entry>integer</entry>
2900           </row><row><entry spanname="descr">This control sets the
2901 camera's aperture to the specified value. The unit is undefined.
2902 Larger values open the iris wider, smaller values close it.</entry>
2903           </row>
2904           <row><entry></entry></row>
2905
2906           <row>
2907             <entry spanname="id"><constant>V4L2_CID_IRIS_RELATIVE</constant>&nbsp;</entry>
2908             <entry>integer</entry>
2909           </row><row><entry spanname="descr">This control modifies the
2910 camera's aperture by the specified amount. The unit is undefined.
2911 Positive values open the iris one step further, negative values close
2912 it one step further. This is a write-only control.</entry>
2913           </row>
2914           <row><entry></entry></row>
2915
2916           <row>
2917             <entry spanname="id"><constant>V4L2_CID_PRIVACY</constant>&nbsp;</entry>
2918             <entry>boolean</entry>
2919           </row><row><entry spanname="descr">Prevent video from being acquired
2920 by the camera. When this control is set to <constant>TRUE</constant> (1), no
2921 image can be captured by the camera. Common means to enforce privacy are
2922 mechanical obturation of the sensor and firmware image processing, but the
2923 device is not restricted to these methods. Devices that implement the privacy
2924 control must support read access and may support write access.</entry>
2925           </row>
2926
2927           <row>
2928             <entry spanname="id"><constant>V4L2_CID_BAND_STOP_FILTER</constant>&nbsp;</entry>
2929             <entry>integer</entry>
2930           </row><row><entry spanname="descr">Switch the band-stop filter of a
2931 camera sensor on or off, or specify its strength. Such band-stop filters can
2932 be used, for example, to filter out the fluorescent light component.</entry>
2933           </row>
2934           <row><entry></entry></row>
2935         </tbody>
2936       </tgroup>
2937     </table>
2938   </section>
2939
2940     <section id="fm-tx-controls">
2941       <title>FM Transmitter Control Reference</title>
2942
2943       <para>The FM Transmitter (FM_TX) class includes controls for common features of
2944 FM transmissions capable devices. Currently this class includes parameters for audio
2945 compression, pilot tone generation, audio deviation limiter, RDS transmission and
2946 tuning power features.</para>
2947
2948       <table pgwide="1" frame="none" id="fm-tx-control-id">
2949       <title>FM_TX Control IDs</title>
2950
2951       <tgroup cols="4">
2952         <colspec colname="c1" colwidth="1*" />
2953         <colspec colname="c2" colwidth="6*" />
2954         <colspec colname="c3" colwidth="2*" />
2955         <colspec colname="c4" colwidth="6*" />
2956         <spanspec namest="c1" nameend="c2" spanname="id" />
2957         <spanspec namest="c2" nameend="c4" spanname="descr" />
2958         <thead>
2959           <row>
2960             <entry spanname="id" align="left">ID</entry>
2961             <entry align="left">Type</entry>
2962           </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
2963           </row>
2964         </thead>
2965         <tbody valign="top">
2966           <row><entry></entry></row>
2967           <row>
2968             <entry spanname="id"><constant>V4L2_CID_FM_TX_CLASS</constant>&nbsp;</entry>
2969             <entry>class</entry>
2970           </row><row><entry spanname="descr">The FM_TX class
2971 descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a
2972 description of this control class.</entry>
2973           </row>
2974           <row>
2975             <entry spanname="id"><constant>V4L2_CID_RDS_TX_DEVIATION</constant>&nbsp;</entry>
2976             <entry>integer</entry>
2977           </row>
2978           <row><entry spanname="descr">Configures RDS signal frequency deviation level in Hz.
2979 The range and step are driver-specific.</entry>
2980           </row>
2981           <row>
2982             <entry spanname="id"><constant>V4L2_CID_RDS_TX_PI</constant>&nbsp;</entry>
2983             <entry>integer</entry>
2984           </row>
2985           <row><entry spanname="descr">Sets the RDS Programme Identification field
2986 for transmission.</entry>
2987           </row>
2988           <row>
2989             <entry spanname="id"><constant>V4L2_CID_RDS_TX_PTY</constant>&nbsp;</entry>
2990             <entry>integer</entry>
2991           </row>
2992           <row><entry spanname="descr">Sets the RDS Programme Type field for transmission.
2993 This encodes up to 31 pre-defined programme types.</entry>
2994           </row>
2995           <row>
2996             <entry spanname="id"><constant>V4L2_CID_RDS_TX_PS_NAME</constant>&nbsp;</entry>
2997             <entry>string</entry>
2998           </row>
2999           <row><entry spanname="descr">Sets the Programme Service name (PS_NAME) for transmission.
3000 It is intended for static display on a receiver. It is the primary aid to listeners in programme service
3001 identification and selection.  In Annex E of <xref linkend="en50067" />, the RDS specification,
3002 there is a full description of the correct character encoding for Programme Service name strings.
3003 Also from RDS specification, PS is usually a single eight character text. However, it is also possible
3004 to find receivers which can scroll strings sized as 8 x N characters. So, this control must be configured
3005 with steps of 8 characters. The result is it must always contain a string with size multiple of 8.</entry>
3006           </row>
3007           <row>
3008             <entry spanname="id"><constant>V4L2_CID_RDS_TX_RADIO_TEXT</constant>&nbsp;</entry>
3009             <entry>string</entry>
3010           </row>
3011           <row><entry spanname="descr">Sets the Radio Text info for transmission. It is a textual description of
3012 what is being broadcasted. RDS Radio Text can be applied when broadcaster wishes to transmit longer PS names,
3013 programme-related information or any other text. In these cases, RadioText should be used in addition to
3014 <constant>V4L2_CID_RDS_TX_PS_NAME</constant>. The encoding for Radio Text strings is also fully described
3015 in Annex E of <xref linkend="en50067" />. The length of Radio Text strings depends on which RDS Block is being
3016 used to transmit it, either 32 (2A block) or 64 (2B block).  However, it is also possible
3017 to find receivers which can scroll strings sized as 32 x N or 64 x N characters. So, this control must be configured
3018 with steps of 32 or 64 characters. The result is it must always contain a string with size multiple of 32 or 64. </entry>
3019           </row>
3020           <row>
3021             <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_ENABLED</constant>&nbsp;</entry>
3022             <entry>boolean</entry>
3023           </row>
3024           <row><entry spanname="descr">Enables or disables the audio deviation limiter feature.
3025 The limiter is useful when trying to maximize the audio volume, minimize receiver-generated
3026 distortion and prevent overmodulation.
3027 </entry>
3028           </row>
3029           <row>
3030             <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_RELEASE_TIME</constant>&nbsp;</entry>
3031             <entry>integer</entry>
3032           </row>
3033           <row><entry spanname="descr">Sets the audio deviation limiter feature release time.
3034 Unit is in useconds. Step and range are driver-specific.</entry>
3035           </row>
3036           <row>
3037             <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_DEVIATION</constant>&nbsp;</entry>
3038             <entry>integer</entry>
3039           </row>
3040           <row><entry spanname="descr">Configures audio frequency deviation level in Hz.
3041 The range and step are driver-specific.</entry>
3042           </row>
3043           <row>
3044             <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ENABLED</constant>&nbsp;</entry>
3045             <entry>boolean</entry>
3046           </row>
3047           <row><entry spanname="descr">Enables or disables the audio compression feature.
3048 This feature amplifies signals below the threshold by a fixed gain and compresses audio
3049 signals above the threshold by the ratio of Threshold/(Gain + Threshold).</entry>
3050           </row>
3051           <row>
3052             <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_GAIN</constant>&nbsp;</entry>
3053             <entry>integer</entry>
3054           </row>
3055           <row><entry spanname="descr">Sets the gain for audio compression feature. It is
3056 a dB value. The range and step are driver-specific.</entry>
3057           </row>
3058           <row>
3059             <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_THRESHOLD</constant>&nbsp;</entry>
3060             <entry>integer</entry>
3061           </row>
3062           <row><entry spanname="descr">Sets the threshold level for audio compression freature.
3063 It is a dB value. The range and step are driver-specific.</entry>
3064           </row>
3065           <row>
3066             <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME</constant>&nbsp;</entry>
3067             <entry>integer</entry>
3068           </row>
3069           <row><entry spanname="descr">Sets the attack time for audio compression feature.
3070 It is a useconds value. The range and step are driver-specific.</entry>
3071           </row>
3072           <row>
3073             <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME</constant>&nbsp;</entry>
3074             <entry>integer</entry>
3075           </row>
3076           <row><entry spanname="descr">Sets the release time for audio compression feature.
3077 It is a useconds value. The range and step are driver-specific.</entry>
3078           </row>
3079           <row>
3080             <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_ENABLED</constant>&nbsp;</entry>
3081             <entry>boolean</entry>
3082           </row>
3083           <row><entry spanname="descr">Enables or disables the pilot tone generation feature.</entry>
3084           </row>
3085           <row>
3086             <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_DEVIATION</constant>&nbsp;</entry>
3087             <entry>integer</entry>
3088           </row>
3089           <row><entry spanname="descr">Configures pilot tone frequency deviation level. Unit is
3090 in Hz. The range and step are driver-specific.</entry>
3091           </row>
3092           <row>
3093             <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_FREQUENCY</constant>&nbsp;</entry>
3094             <entry>integer</entry>
3095           </row>
3096           <row><entry spanname="descr">Configures pilot tone frequency value. Unit is
3097 in Hz. The range and step are driver-specific.</entry>
3098           </row>
3099           <row>
3100             <entry spanname="id"><constant>V4L2_CID_TUNE_PREEMPHASIS</constant>&nbsp;</entry>
3101             <entry>integer</entry>
3102           </row>
3103           <row id="v4l2-preemphasis"><entry spanname="descr">Configures the pre-emphasis value for broadcasting.
3104 A pre-emphasis filter is applied to the broadcast to accentuate the high audio frequencies.
3105 Depending on the region, a time constant of either 50 or 75 useconds is used. The enum&nbsp;v4l2_preemphasis
3106 defines possible values for pre-emphasis. Here they are:</entry>
3107         </row><row>
3108         <entrytbl spanname="descr" cols="2">
3109                   <tbody valign="top">
3110                     <row>
3111                       <entry><constant>V4L2_PREEMPHASIS_DISABLED</constant>&nbsp;</entry>
3112                       <entry>No pre-emphasis is applied.</entry>
3113                     </row>
3114                     <row>
3115                       <entry><constant>V4L2_PREEMPHASIS_50_uS</constant>&nbsp;</entry>
3116                       <entry>A pre-emphasis of 50 uS is used.</entry>
3117                     </row>
3118                     <row>
3119                       <entry><constant>V4L2_PREEMPHASIS_75_uS</constant>&nbsp;</entry>
3120                       <entry>A pre-emphasis of 75 uS is used.</entry>
3121                     </row>
3122                   </tbody>
3123                 </entrytbl>
3124
3125           </row>
3126           <row>
3127             <entry spanname="id"><constant>V4L2_CID_TUNE_POWER_LEVEL</constant>&nbsp;</entry>
3128             <entry>integer</entry>
3129           </row>
3130           <row><entry spanname="descr">Sets the output power level for signal transmission.
3131 Unit is in dBuV. Range and step are driver-specific.</entry>
3132           </row>
3133           <row>
3134             <entry spanname="id"><constant>V4L2_CID_TUNE_ANTENNA_CAPACITOR</constant>&nbsp;</entry>
3135             <entry>integer</entry>
3136           </row>
3137           <row><entry spanname="descr">This selects the value of antenna tuning capacitor
3138 manually or automatically if set to zero. Unit, range and step are driver-specific.</entry>
3139           </row>
3140           <row><entry></entry></row>
3141         </tbody>
3142       </tgroup>
3143       </table>
3144
3145 <para>For more details about RDS specification, refer to
3146 <xref linkend="en50067" /> document, from CENELEC.</para>
3147     </section>
3148
3149     <section id="flash-controls">
3150       <title>Flash Control Reference</title>
3151
3152       <note>
3153         <title>Experimental</title>
3154
3155         <para>This is an <link linkend="experimental">experimental</link>
3156 interface and may change in the future.</para>
3157       </note>
3158
3159       <para>
3160         The V4L2 flash controls are intended to provide generic access
3161         to flash controller devices. Flash controller devices are
3162         typically used in digital cameras.
3163       </para>
3164
3165       <para>
3166         The interface can support both LED and xenon flash devices. As
3167         of writing this, there is no xenon flash driver using this
3168         interface.
3169       </para>
3170
3171       <section id="flash-controls-use-cases">
3172         <title>Supported use cases</title>
3173
3174         <section>
3175           <title>Unsynchronised LED flash (software strobe)</title>
3176
3177           <para>
3178             Unsynchronised LED flash is controlled directly by the
3179             host as the sensor. The flash must be enabled by the host
3180             before the exposure of the image starts and disabled once
3181             it ends. The host is fully responsible for the timing of
3182             the flash.
3183           </para>
3184
3185           <para>Example of such device: Nokia N900.</para>
3186         </section>
3187
3188         <section>
3189           <title>Synchronised LED flash (hardware strobe)</title>
3190
3191           <para>
3192             The synchronised LED flash is pre-programmed by the host
3193             (power and timeout) but controlled by the sensor through a
3194             strobe signal from the sensor to the flash.
3195           </para>
3196
3197           <para>
3198             The sensor controls the flash duration and timing. This
3199             information typically must be made available to the
3200             sensor.
3201           </para>
3202
3203         </section>
3204
3205         <section>
3206           <title>LED flash as torch</title>
3207
3208           <para>
3209             LED flash may be used as torch in conjunction with another
3210             use case involving camera or individually.
3211           </para>
3212
3213         </section>
3214
3215       </section>
3216
3217       <table pgwide="1" frame="none" id="flash-control-id">
3218       <title>Flash Control IDs</title>
3219
3220       <tgroup cols="4">
3221         <colspec colname="c1" colwidth="1*" />
3222         <colspec colname="c2" colwidth="6*" />
3223         <colspec colname="c3" colwidth="2*" />
3224         <colspec colname="c4" colwidth="6*" />
3225         <spanspec namest="c1" nameend="c2" spanname="id" />
3226         <spanspec namest="c2" nameend="c4" spanname="descr" />
3227         <thead>
3228           <row>
3229             <entry spanname="id" align="left">ID</entry>
3230             <entry align="left">Type</entry>
3231           </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
3232           </row>
3233         </thead>
3234         <tbody valign="top">
3235           <row><entry></entry></row>
3236           <row>
3237             <entry spanname="id"><constant>V4L2_CID_FLASH_CLASS</constant></entry>
3238             <entry>class</entry>
3239           </row>
3240           <row>
3241             <entry spanname="descr">The FLASH class descriptor.</entry>
3242           </row>
3243           <row>
3244             <entry spanname="id"><constant>V4L2_CID_FLASH_LED_MODE</constant></entry>
3245             <entry>menu</entry>
3246           </row>
3247           <row id="v4l2-flash-led-mode">
3248             <entry spanname="descr">Defines the mode of the flash LED,
3249             the high-power white LED attached to the flash controller.
3250             Setting this control may not be possible in presence of
3251             some faults. See V4L2_CID_FLASH_FAULT.</entry>
3252           </row>
3253           <row>
3254             <entrytbl spanname="descr" cols="2">
3255               <tbody valign="top">
3256                 <row>
3257                   <entry><constant>V4L2_FLASH_LED_MODE_NONE</constant></entry>
3258                   <entry>Off.</entry>
3259                 </row>
3260                 <row>
3261                   <entry><constant>V4L2_FLASH_LED_MODE_FLASH</constant></entry>
3262                   <entry>Flash mode.</entry>
3263                 </row>
3264                 <row>
3265                   <entry><constant>V4L2_FLASH_LED_MODE_TORCH</constant></entry>
3266                   <entry>Torch mode. See V4L2_CID_FLASH_TORCH_INTENSITY.</entry>
3267                 </row>
3268               </tbody>
3269             </entrytbl>
3270           </row>
3271           <row>
3272             <entry spanname="id"><constant>V4L2_CID_FLASH_STROBE_SOURCE</constant></entry>
3273             <entry>menu</entry>
3274           </row>
3275           <row id="v4l2-flash-strobe-source"><entry
3276           spanname="descr">Defines the source of the flash LED
3277           strobe.</entry>
3278           </row>
3279           <row>
3280             <entrytbl spanname="descr" cols="2">
3281               <tbody valign="top">
3282                 <row>
3283                   <entry><constant>V4L2_FLASH_STROBE_SOURCE_SOFTWARE</constant></entry>
3284                   <entry>The flash strobe is triggered by using
3285                   the V4L2_CID_FLASH_STROBE control.</entry>
3286                 </row>
3287                 <row>
3288                   <entry><constant>V4L2_FLASH_STROBE_SOURCE_EXTERNAL</constant></entry>
3289                   <entry>The flash strobe is triggered by an
3290                   external source. Typically this is a sensor,
3291                   which makes it possible to synchronises the
3292                   flash strobe start to exposure start.</entry>
3293                 </row>
3294               </tbody>
3295             </entrytbl>
3296           </row>
3297           <row>
3298             <entry spanname="id"><constant>V4L2_CID_FLASH_STROBE</constant></entry>
3299             <entry>button</entry>
3300           </row>
3301           <row>
3302             <entry spanname="descr">Strobe flash. Valid when
3303             V4L2_CID_FLASH_LED_MODE is set to
3304             V4L2_FLASH_LED_MODE_FLASH and V4L2_CID_FLASH_STROBE_SOURCE
3305             is set to V4L2_FLASH_STROBE_SOURCE_SOFTWARE. Setting this
3306             control may not be possible in presence of some faults.
3307             See V4L2_CID_FLASH_FAULT.</entry>
3308           </row>
3309           <row>
3310             <entry spanname="id"><constant>V4L2_CID_FLASH_STROBE_STOP</constant></entry>
3311             <entry>button</entry>
3312           </row>
3313           <row><entry spanname="descr">Stop flash strobe immediately.</entry>
3314           </row>
3315           <row>
3316             <entry spanname="id"><constant>V4L2_CID_FLASH_STROBE_STATUS</constant></entry>
3317             <entry>boolean</entry>
3318           </row>
3319           <row>
3320             <entry spanname="descr">Strobe status: whether the flash
3321             is strobing at the moment or not. This is a read-only
3322             control.</entry>
3323           </row>
3324           <row>
3325             <entry spanname="id"><constant>V4L2_CID_FLASH_TIMEOUT</constant></entry>
3326             <entry>integer</entry>
3327           </row>
3328           <row>
3329             <entry spanname="descr">Hardware timeout for flash. The
3330             flash strobe is stopped after this period of time has
3331             passed from the start of the strobe.</entry>
3332           </row>
3333           <row>
3334             <entry spanname="id"><constant>V4L2_CID_FLASH_INTENSITY</constant></entry>
3335             <entry>integer</entry>
3336           </row>
3337           <row>
3338             <entry spanname="descr">Intensity of the flash strobe when
3339             the flash LED is in flash mode
3340             (V4L2_FLASH_LED_MODE_FLASH). The unit should be milliamps
3341             (mA) if possible.</entry>
3342           </row>
3343           <row>
3344             <entry spanname="id"><constant>V4L2_CID_FLASH_TORCH_INTENSITY</constant></entry>
3345             <entry>integer</entry>
3346           </row>
3347           <row>
3348             <entry spanname="descr">Intensity of the flash LED in
3349             torch mode (V4L2_FLASH_LED_MODE_TORCH). The unit should be
3350             milliamps (mA) if possible. Setting this control may not
3351             be possible in presence of some faults. See
3352             V4L2_CID_FLASH_FAULT.</entry>
3353           </row>
3354           <row>
3355             <entry spanname="id"><constant>V4L2_CID_FLASH_INDICATOR_INTENSITY</constant></entry>
3356             <entry>integer</entry>
3357           </row>
3358           <row>
3359             <entry spanname="descr">Intensity of the indicator LED.
3360             The indicator LED may be fully independent of the flash
3361             LED. The unit should be microamps (uA) if possible.</entry>
3362           </row>
3363           <row>
3364             <entry spanname="id"><constant>V4L2_CID_FLASH_FAULT</constant></entry>
3365             <entry>bitmask</entry>
3366           </row>
3367           <row>
3368             <entry spanname="descr">Faults related to the flash. The
3369             faults tell about specific problems in the flash chip
3370             itself or the LEDs attached to it. Faults may prevent
3371             further use of some of the flash controls. In particular,
3372             V4L2_CID_FLASH_LED_MODE is set to V4L2_FLASH_LED_MODE_NONE
3373             if the fault affects the flash LED. Exactly which faults
3374             have such an effect is chip dependent. Reading the faults
3375             resets the control and returns the chip to a usable state
3376             if possible.</entry>
3377           </row>
3378           <row>
3379             <entrytbl spanname="descr" cols="2">
3380               <tbody valign="top">
3381                 <row>
3382                   <entry><constant>V4L2_FLASH_FAULT_OVER_VOLTAGE</constant></entry>
3383                   <entry>Flash controller voltage to the flash LED
3384                   has exceeded the limit specific to the flash
3385                   controller.</entry>
3386                 </row>
3387                 <row>
3388                   <entry><constant>V4L2_FLASH_FAULT_TIMEOUT</constant></entry>
3389                   <entry>The flash strobe was still on when
3390                   the timeout set by the user ---
3391                   V4L2_CID_FLASH_TIMEOUT control --- has expired.
3392                   Not all flash controllers may set this in all
3393                   such conditions.</entry>
3394                 </row>
3395                 <row>
3396                   <entry><constant>V4L2_FLASH_FAULT_OVER_TEMPERATURE</constant></entry>
3397                   <entry>The flash controller has overheated.</entry>
3398                 </row>
3399                 <row>
3400                   <entry><constant>V4L2_FLASH_FAULT_SHORT_CIRCUIT</constant></entry>
3401                   <entry>The short circuit protection of the flash
3402                   controller has been triggered.</entry>
3403                 </row>
3404                 <row>
3405                   <entry><constant>V4L2_FLASH_FAULT_OVER_CURRENT</constant></entry>
3406                   <entry>Current in the LED power supply has exceeded the limit
3407                   specific to the flash controller.</entry>
3408                 </row>
3409                 <row>
3410                   <entry><constant>V4L2_FLASH_FAULT_INDICATOR</constant></entry>
3411                   <entry>The flash controller has detected a short or open
3412                   circuit condition on the indicator LED.</entry>
3413                 </row>
3414               </tbody>
3415             </entrytbl>
3416           </row>
3417           <row>
3418             <entry spanname="id"><constant>V4L2_CID_FLASH_CHARGE</constant></entry>
3419             <entry>boolean</entry>
3420           </row>
3421           <row><entry spanname="descr">Enable or disable charging of the xenon
3422           flash capacitor.</entry>
3423           </row>
3424           <row>
3425             <entry spanname="id"><constant>V4L2_CID_FLASH_READY</constant></entry>
3426             <entry>boolean</entry>
3427           </row>
3428           <row>
3429             <entry spanname="descr">Is the flash ready to strobe?
3430             Xenon flashes require their capacitors charged before
3431             strobing. LED flashes often require a cooldown period
3432             after strobe during which another strobe will not be
3433             possible. This is a read-only control.</entry>
3434           </row>
3435           <row><entry></entry></row>
3436         </tbody>
3437       </tgroup>
3438       </table>
3439     </section>
3440
3441     <section id="jpeg-controls">
3442       <title>JPEG Control Reference</title>
3443       <para>The JPEG class includes controls for common features of JPEG
3444       encoders and decoders. Currently it includes features for codecs
3445       implementing progressive baseline DCT compression process with
3446       Huffman entrophy coding.</para>
3447       <table pgwide="1" frame="none" id="jpeg-control-id">
3448       <title>JPEG Control IDs</title>
3449
3450       <tgroup cols="4">
3451         <colspec colname="c1" colwidth="1*" />
3452         <colspec colname="c2" colwidth="6*" />
3453         <colspec colname="c3" colwidth="2*" />
3454         <colspec colname="c4" colwidth="6*" />
3455         <spanspec namest="c1" nameend="c2" spanname="id" />
3456         <spanspec namest="c2" nameend="c4" spanname="descr" />
3457         <thead>
3458           <row>
3459             <entry spanname="id" align="left">ID</entry>
3460             <entry align="left">Type</entry>
3461           </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
3462           </row>
3463         </thead>
3464         <tbody valign="top">
3465           <row><entry></entry></row>
3466           <row>
3467             <entry spanname="id"><constant>V4L2_CID_JPEG_CLASS</constant>&nbsp;</entry>
3468             <entry>class</entry>
3469           </row><row><entry spanname="descr">The JPEG class descriptor. Calling
3470           &VIDIOC-QUERYCTRL; for this control will return a description of this
3471           control class.
3472
3473         </entry>
3474           </row>
3475           <row>
3476             <entry spanname="id"><constant>V4L2_CID_JPEG_CHROMA_SUBSAMPLING</constant></entry>
3477             <entry>menu</entry>
3478           </row>
3479           <row id="jpeg-chroma-subsampling-control">
3480             <entry spanname="descr">The chroma subsampling factors describe how
3481             each component of an input image is sampled, in respect to maximum
3482             sample rate in each spatial dimension. See <xref linkend="itu-t81"/>,
3483             clause A.1.1. for more details. The <constant>
3484             V4L2_CID_JPEG_CHROMA_SUBSAMPLING</constant> control determines how
3485             Cb and Cr components are downsampled after coverting an input image
3486             from RGB to Y'CbCr color space.
3487             </entry>
3488           </row>
3489           <row>
3490             <entrytbl spanname="descr" cols="2">
3491               <tbody valign="top">
3492                 <row>
3493                   <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_444</constant>
3494                   </entry><entry>No chroma subsampling, each pixel has
3495                   Y, Cr and Cb values.</entry>
3496                 </row>
3497                 <row>
3498                   <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_422</constant>
3499                   </entry><entry>Horizontally subsample Cr, Cb components
3500                   by a factor of 2.</entry>
3501                 </row>
3502                 <row>
3503                   <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_420</constant>
3504                   </entry><entry>Subsample Cr, Cb components horizontally
3505                   and vertically by 2.</entry>
3506                 </row>
3507                 <row>
3508                   <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_411</constant>
3509                   </entry><entry>Horizontally subsample Cr, Cb components
3510                   by a factor of 4.</entry>
3511                 </row>
3512                 <row>
3513                   <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_410</constant>
3514                   </entry><entry>Subsample Cr, Cb components horizontally
3515                   by 4 and vertically by 2.</entry>
3516                 </row>
3517                 <row>
3518                   <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_GRAY</constant>
3519                   </entry><entry>Use only luminance component.</entry>
3520                 </row>
3521               </tbody>
3522             </entrytbl>
3523           </row>
3524           <row>
3525             <entry spanname="id"><constant>V4L2_CID_JPEG_RESTART_INTERVAL</constant>
3526             </entry><entry>integer</entry>
3527           </row>
3528           <row><entry spanname="descr">
3529               The restart interval determines an interval of inserting RSTm
3530               markers (m = 0..7). The purpose of these markers is to additionally
3531               reinitialize the encoder process, in order to process blocks of
3532               an image independently.
3533               For the lossy compression processes the restart interval unit is
3534               MCU (Minimum Coded Unit) and its value is contained in DRI
3535               (Define Restart Interval) marker. If <constant>
3536               V4L2_CID_JPEG_RESTART_INTERVAL</constant> control is set to 0,
3537               DRI and RSTm markers will not be inserted.
3538             </entry>
3539           </row>
3540           <row id="jpeg-quality-control">
3541             <entry spanname="id"><constant>V4L2_CID_JPEG_COMPRESION_QUALITY</constant></entry>
3542             <entry>integer</entry>
3543           </row>
3544           <row>
3545             <entry spanname="descr">
3546               <constant>V4L2_CID_JPEG_COMPRESION_QUALITY</constant> control
3547               determines trade-off between image quality and size.
3548               It provides simpler method for applications to control image quality,
3549               without a need for direct reconfiguration of luminance and chrominance
3550               quantization tables.
3551
3552               In cases where a driver uses quantization tables configured directly
3553               by an application, using interfaces defined elsewhere, <constant>
3554               V4L2_CID_JPEG_COMPRESION_QUALITY</constant> control should be set
3555               by driver to 0.
3556
3557               <para>The value range of this control is driver-specific. Only
3558               positive, non-zero values are meaningful. The recommended range
3559               is 1 - 100, where larger values correspond to better image quality.
3560               </para>
3561             </entry>
3562             </row>
3563           <row id="jpeg-active-marker-control">
3564             <entry spanname="id"><constant>V4L2_CID_JPEG_ACTIVE_MARKER</constant></entry>
3565             <entry>bitmask</entry>
3566           </row>
3567           <row>
3568             <entry spanname="descr">Specify which JPEG markers are included
3569             in compressed stream. This control is valid only for encoders.
3570             </entry>
3571           </row>
3572           <row>
3573             <entrytbl spanname="descr" cols="2">
3574               <tbody valign="top">
3575                 <row>
3576                   <entry><constant>V4L2_JPEG_ACTIVE_MARKER_APP0</constant></entry>
3577                   <entry>Application data segment APP<subscript>0</subscript>.</entry>
3578                 </row><row>
3579                   <entry><constant>V4L2_JPEG_ACTIVE_MARKER_APP1</constant></entry>
3580                   <entry>Application data segment APP<subscript>1</subscript>.</entry>
3581                 </row><row>
3582                   <entry><constant>V4L2_JPEG_ACTIVE_MARKER_COM</constant></entry>
3583                   <entry>Comment segment.</entry>
3584                 </row><row>
3585                   <entry><constant>V4L2_JPEG_ACTIVE_MARKER_DQT</constant></entry>
3586                   <entry>Quantization tables segment.</entry>
3587                 </row><row>
3588                   <entry><constant>V4L2_JPEG_ACTIVE_MARKER_DHT</constant></entry>
3589                   <entry>Huffman tables segment.</entry>
3590                 </row>
3591               </tbody>
3592             </entrytbl>
3593           </row>
3594           <row><entry></entry></row>
3595         </tbody>
3596       </tgroup>
3597       </table>
3598       <para>For more details about JPEG specification, refer
3599       to <xref linkend="itu-t81"/>, <xref linkend="jfif"/>,
3600       <xref linkend="w3c-jpeg-jfif"/>.</para>
3601     </section>
3602 </section>