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V4L/DVB: V4L: v4l2-subdev driver for AK8813 and AK8814 TV-encoders from AKM
[mirror_ubuntu-kernels.git] / Documentation / DocBook / v4l / controls.xml
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8e080c2e
MCC		 1 <section id="control">
2 <title>User Controls</title>
3
4 <para>Devices typically have a number of user-settable controls
5such as brightness, saturation and so on, which would be presented to
6the user on a graphical user interface. But, different devices
7will have different controls available, and furthermore, the range of
8possible values, and the default value will vary from device to
9device. The control ioctls provide the information and a mechanism to
10create a nice user interface for these controls that will work
11correctly with any device.</para>
12
13 <para>All controls are accessed using an ID value. V4L2 defines
14several IDs for specific purposes. Drivers can also implement their
15own custom controls using <constant>V4L2_CID_PRIVATE_BASE</constant>
16and higher values. The pre-defined control IDs have the prefix
17<constant>V4L2_CID_</constant>, and are listed in <xref
18linkend="control-id" />. The ID is used when querying the attributes of
19a control, and when getting or setting the current value.</para>
20
21 <para>Generally applications should present controls to the user
22without assumptions about their purpose. Each control comes with a
23name string the user is supposed to understand. When the purpose is
24non-intuitive the driver writer should provide a user manual, a user
25interface plug-in or a driver specific panel application. Predefined
26IDs were introduced to change a few controls programmatically, for
27example to mute a device during a channel switch.</para>
28
29 <para>Drivers may enumerate different controls after switching
30the current video input or output, tuner or modulator, or audio input
31or output. Different in the sense of other bounds, another default and
32current value, step size or other menu items. A control with a certain
33<emphasis>custom</emphasis> ID can also change name and
34type.<footnote>
35 <para>It will be more convenient for applications if drivers
36make use of the <constant>V4L2_CTRL_FLAG_DISABLED</constant> flag, but
37that was never required.</para>
38 </footnote> Control values are stored globally, they do not
39change when switching except to stay within the reported bounds. They
40also do not change &eg; when the device is opened or closed, when the
41tuner radio frequency is changed or generally never without
42application request. Since V4L2 specifies no event mechanism, panel
43applications intended to cooperate with other panel applications (be
44they built into a larger application, as a TV viewer) may need to
45regularly poll control values to update their user
46interface.<footnote>
47 <para>Applications could call an ioctl to request events.
48After another process called &VIDIOC-S-CTRL; or another ioctl changing
49shared properties the &func-select; function would indicate
50readability until any ioctl (querying the properties) is
51called.</para>
52 </footnote></para>
53
54 <table pgwide="1" frame="none" id="control-id">
55 <title>Control IDs</title>
56 <tgroup cols="3">
57 &cs-def;
58 <thead>
59 <row>
60 <entry>ID</entry>
61 <entry>Type</entry>
62 <entry>Description</entry>
63 </row>
64 </thead>
65 <tbody valign="top">
66 <row>
67 <entry><constant>V4L2_CID_BASE</constant></entry>
68 <entry></entry>
69 <entry>First predefined ID, equal to
70<constant>V4L2_CID_BRIGHTNESS</constant>.</entry>
71 </row>
72 <row>
73 <entry><constant>V4L2_CID_USER_BASE</constant></entry>
74 <entry></entry>
75 <entry>Synonym of <constant>V4L2_CID_BASE</constant>.</entry>
76 </row>
77 <row>
78 <entry><constant>V4L2_CID_BRIGHTNESS</constant></entry>
79 <entry>integer</entry>
80 <entry>Picture brightness, or more precisely, the black
81level.</entry>
82 </row>
83 <row>
84 <entry><constant>V4L2_CID_CONTRAST</constant></entry>
85 <entry>integer</entry>
86 <entry>Picture contrast or luma gain.</entry>
87 </row>
88 <row>
89 <entry><constant>V4L2_CID_SATURATION</constant></entry>
90 <entry>integer</entry>
91 <entry>Picture color saturation or chroma gain.</entry>
92 </row>
93 <row>
94 <entry><constant>V4L2_CID_HUE</constant></entry>
95 <entry>integer</entry>
96 <entry>Hue or color balance.</entry>
97 </row>
98 <row>
99 <entry><constant>V4L2_CID_AUDIO_VOLUME</constant></entry>
100 <entry>integer</entry>
101 <entry>Overall audio volume. Note some drivers also
102provide an OSS or ALSA mixer interface.</entry>
103 </row>
104 <row>
105 <entry><constant>V4L2_CID_AUDIO_BALANCE</constant></entry>
106 <entry>integer</entry>
107 <entry>Audio stereo balance. Minimum corresponds to all
108the way left, maximum to right.</entry>
109 </row>
110 <row>
111 <entry><constant>V4L2_CID_AUDIO_BASS</constant></entry>
112 <entry>integer</entry>
113 <entry>Audio bass adjustment.</entry>
114 </row>
115 <row>
116 <entry><constant>V4L2_CID_AUDIO_TREBLE</constant></entry>
117 <entry>integer</entry>
118 <entry>Audio treble adjustment.</entry>
119 </row>
120 <row>
121 <entry><constant>V4L2_CID_AUDIO_MUTE</constant></entry>
122 <entry>boolean</entry>
123 <entry>Mute audio, &ie; set the volume to zero, however
124without affecting <constant>V4L2_CID_AUDIO_VOLUME</constant>. Like
125ALSA drivers, V4L2 drivers must mute at load time to avoid excessive
126noise. Actually the entire device should be reset to a low power
127consumption state.</entry>
128 </row>
129 <row>
130 <entry><constant>V4L2_CID_AUDIO_LOUDNESS</constant></entry>
131 <entry>boolean</entry>
132 <entry>Loudness mode (bass boost).</entry>
133 </row>
134 <row>
135 <entry><constant>V4L2_CID_BLACK_LEVEL</constant></entry>
136 <entry>integer</entry>
137 <entry>Another name for brightness (not a synonym of
138<constant>V4L2_CID_BRIGHTNESS</constant>). This control is deprecated
139and should not be used in new drivers and applications.</entry>
140 </row>
141 <row>
142 <entry><constant>V4L2_CID_AUTO_WHITE_BALANCE</constant></entry>
143 <entry>boolean</entry>
144 <entry>Automatic white balance (cameras).</entry>
145 </row>
146 <row>
147 <entry><constant>V4L2_CID_DO_WHITE_BALANCE</constant></entry>
148 <entry>button</entry>
149 <entry>This is an action control. When set (the value is
150ignored), the device will do a white balance and then hold the current
151setting. Contrast this with the boolean
152<constant>V4L2_CID_AUTO_WHITE_BALANCE</constant>, which, when
153activated, keeps adjusting the white balance.</entry>
154 </row>
155 <row>
156 <entry><constant>V4L2_CID_RED_BALANCE</constant></entry>
157 <entry>integer</entry>
158 <entry>Red chroma balance.</entry>
159 </row>
160 <row>
161 <entry><constant>V4L2_CID_BLUE_BALANCE</constant></entry>
162 <entry>integer</entry>
163 <entry>Blue chroma balance.</entry>
164 </row>
165 <row>
166 <entry><constant>V4L2_CID_GAMMA</constant></entry>
167 <entry>integer</entry>
168 <entry>Gamma adjust.</entry>
169 </row>
170 <row>
171 <entry><constant>V4L2_CID_WHITENESS</constant></entry>
172 <entry>integer</entry>
173 <entry>Whiteness for grey-scale devices. This is a synonym
174for <constant>V4L2_CID_GAMMA</constant>. This control is deprecated
175and should not be used in new drivers and applications.</entry>
176 </row>
177 <row>
178 <entry><constant>V4L2_CID_EXPOSURE</constant></entry>
179 <entry>integer</entry>
180 <entry>Exposure (cameras). [Unit?]</entry>
181 </row>
182 <row>
183 <entry><constant>V4L2_CID_AUTOGAIN</constant></entry>
184 <entry>boolean</entry>
185 <entry>Automatic gain/exposure control.</entry>
186 </row>
187 <row>
188 <entry><constant>V4L2_CID_GAIN</constant></entry>
189 <entry>integer</entry>
190 <entry>Gain control.</entry>
191 </row>
192 <row>
193 <entry><constant>V4L2_CID_HFLIP</constant></entry>
194 <entry>boolean</entry>
195 <entry>Mirror the picture horizontally.</entry>
196 </row>
197 <row>
198 <entry><constant>V4L2_CID_VFLIP</constant></entry>
199 <entry>boolean</entry>
200 <entry>Mirror the picture vertically.</entry>
201 </row>
202 <row>
203 <entry><constant>V4L2_CID_HCENTER_DEPRECATED</constant> (formerly <constant>V4L2_CID_HCENTER</constant>)</entry>
204 <entry>integer</entry>
205 <entry>Horizontal image centering. This control is
206deprecated. New drivers and applications should use the <link
207linkend="camera-controls">Camera class controls</link>
208<constant>V4L2_CID_PAN_ABSOLUTE</constant>,
209<constant>V4L2_CID_PAN_RELATIVE</constant> and
210<constant>V4L2_CID_PAN_RESET</constant> instead.</entry>
211 </row>
212 <row>
213 <entry><constant>V4L2_CID_VCENTER_DEPRECATED</constant>
214 (formerly <constant>V4L2_CID_VCENTER</constant>)</entry>
215 <entry>integer</entry>
216 <entry>Vertical image centering. Centering is intended to
217<emphasis>physically</emphasis> adjust cameras. For image cropping see
218<xref linkend="crop" />, for clipping <xref linkend="overlay" />. This
219control is deprecated. New drivers and applications should use the
220<link linkend="camera-controls">Camera class controls</link>
221<constant>V4L2_CID_TILT_ABSOLUTE</constant>,
222<constant>V4L2_CID_TILT_RELATIVE</constant> and
223<constant>V4L2_CID_TILT_RESET</constant> instead.</entry>
224 </row>
225 <row id="v4l2-power-line-frequency">
226 <entry><constant>V4L2_CID_POWER_LINE_FREQUENCY</constant></entry>
227 <entry>enum</entry>
228 <entry>Enables a power line frequency filter to avoid
229flicker. Possible values for <constant>enum v4l2_power_line_frequency</constant> are:
230<constant>V4L2_CID_POWER_LINE_FREQUENCY_DISABLED</constant> (0),
231<constant>V4L2_CID_POWER_LINE_FREQUENCY_50HZ</constant> (1) and
232<constant>V4L2_CID_POWER_LINE_FREQUENCY_60HZ</constant> (2).</entry>
233 </row>
234 <row>
235 <entry><constant>V4L2_CID_HUE_AUTO</constant></entry>
236 <entry>boolean</entry>
237 <entry>Enables automatic hue control by the device. The
238effect of setting <constant>V4L2_CID_HUE</constant> while automatic
239hue control is enabled is undefined, drivers should ignore such
240request.</entry>
241 </row>
242 <row>
243 <entry><constant>V4L2_CID_WHITE_BALANCE_TEMPERATURE</constant></entry>
244 <entry>integer</entry>
245 <entry>This control specifies the white balance settings
246as a color temperature in Kelvin. A driver should have a minimum of
2472800 (incandescent) to 6500 (daylight). For more information about
248color temperature see <ulink
249url="http://en.wikipedia.org/wiki/Color_temperature">Wikipedia</ulink>.</entry>
250 </row>
251 <row>
252 <entry><constant>V4L2_CID_SHARPNESS</constant></entry>
253 <entry>integer</entry>
254 <entry>Adjusts the sharpness filters in a camera. The
255minimum value disables the filters, higher values give a sharper
256picture.</entry>
257 </row>
258 <row>
259 <entry><constant>V4L2_CID_BACKLIGHT_COMPENSATION</constant></entry>
260 <entry>integer</entry>
261 <entry>Adjusts the backlight compensation in a camera. The
262minimum value disables backlight compensation.</entry>
263 </row>
264 <row>
265 <entry><constant>V4L2_CID_CHROMA_AGC</constant></entry>
266 <entry>boolean</entry>
267 <entry>Chroma automatic gain control.</entry>
268 </row>
7a01f6db
DH		 269 <row>
270 <entry><constant>V4L2_CID_CHROMA_GAIN</constant></entry>
271 <entry>integer</entry>
272 <entry>Adjusts the Chroma gain control (for use when chroma AGC
273 is disabled).</entry>
274 </row>
8e080c2e
MCC		 275 <row>
276 <entry><constant>V4L2_CID_COLOR_KILLER</constant></entry>
277 <entry>boolean</entry>
278 <entry>Enable the color killer (&ie; force a black &amp; white image in case of a weak video signal).</entry>
279 </row>
280 <row id="v4l2-colorfx">
281 <entry><constant>V4L2_CID_COLORFX</constant></entry>
282 <entry>enum</entry>
283 <entry>Selects a color effect. Possible values for
284<constant>enum v4l2_colorfx</constant> are:
285<constant>V4L2_COLORFX_NONE</constant> (0),
286<constant>V4L2_COLORFX_BW</constant> (1) and
287<constant>V4L2_COLORFX_SEPIA</constant> (2).</entry>
288 </row>
bd977801
VH		 289 <row>
290 <entry><constant>V4L2_CID_ROTATE</constant></entry>
291 <entry>integer</entry>
292 <entry>Rotates the image by specified angle. Common angles are 90,
293 270 and 180. Rotating the image to 90 and 270 will reverse the height
294 and width of the display window. It is necessary to set the new height and
295 width of the picture using the &VIDIOC-S-FMT; ioctl according to
296 the rotation angle selected.</entry>
297 </row>
298 <row>
299 <entry><constant>V4L2_CID_BG_COLOR</constant></entry>
300 <entry>integer</entry>
301 <entry>Sets the background color on the current output device.
302 Background color needs to be specified in the RGB24 format. The
303 supplied 32 bit value is interpreted as bits 0-7 Red color information,
304 bits 8-15 Green color information, bits 16-23 Blue color
305 information and bits 24-31 must be zero.</entry>
306 </row>
8e080c2e
MCC		 307 <row>
308 <entry><constant>V4L2_CID_LASTP1</constant></entry>
309 <entry></entry>
310 <entry>End of the predefined control IDs (currently
bd977801 311<constant>V4L2_CID_BG_COLOR</constant> + 1).</entry>
8e080c2e
MCC		 312 </row>
313 <row>
314 <entry><constant>V4L2_CID_PRIVATE_BASE</constant></entry>
315 <entry></entry>
316 <entry>ID of the first custom (driver specific) control.
317Applications depending on particular custom controls should check the
318driver name and version, see <xref linkend="querycap" />.</entry>
319 </row>
320 </tbody>
321 </tgroup>
322 </table>
323
324 <para>Applications can enumerate the available controls with the
325&VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls, get and set a
326control value with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls.
327Drivers must implement <constant>VIDIOC_QUERYCTRL</constant>,
328<constant>VIDIOC_G_CTRL</constant> and
329<constant>VIDIOC_S_CTRL</constant> when the device has one or more
330controls, <constant>VIDIOC_QUERYMENU</constant> when it has one or
331more menu type controls.</para>
332
333 <example>
334 <title>Enumerating all controls</title>
335
336 <programlisting>
337&v4l2-queryctrl; queryctrl;
338&v4l2-querymenu; querymenu;
339
340static void
341enumerate_menu (void)
342{
343 printf (" Menu items:\n");
344
345 memset (&amp;querymenu, 0, sizeof (querymenu));
346 querymenu.id = queryctrl.id;
347
348 for (querymenu.index = queryctrl.minimum;
349 querymenu.index &lt;= queryctrl.maximum;
350 querymenu.index++) {
351 if (0 == ioctl (fd, &VIDIOC-QUERYMENU;, &amp;querymenu)) {
352 printf (" %s\n", querymenu.name);
353 } else {
354 perror ("VIDIOC_QUERYMENU");
355 exit (EXIT_FAILURE);
356 }
357 }
358}
359
360memset (&amp;queryctrl, 0, sizeof (queryctrl));
361
362for (queryctrl.id = V4L2_CID_BASE;
363 queryctrl.id &lt; V4L2_CID_LASTP1;
364 queryctrl.id++) {
365 if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;queryctrl)) {
366 if (queryctrl.flags &amp; V4L2_CTRL_FLAG_DISABLED)
367 continue;
368
369 printf ("Control %s\n", queryctrl.name);
370
371 if (queryctrl.type == V4L2_CTRL_TYPE_MENU)
372 enumerate_menu ();
373 } else {
374 if (errno == EINVAL)
375 continue;
376
377 perror ("VIDIOC_QUERYCTRL");
378 exit (EXIT_FAILURE);
379 }
380}
381
382for (queryctrl.id = V4L2_CID_PRIVATE_BASE;;
383 queryctrl.id++) {
384 if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;queryctrl)) {
385 if (queryctrl.flags &amp; V4L2_CTRL_FLAG_DISABLED)
386 continue;
387
388 printf ("Control %s\n", queryctrl.name);
389
390 if (queryctrl.type == V4L2_CTRL_TYPE_MENU)
391 enumerate_menu ();
392 } else {
393 if (errno == EINVAL)
394 break;
395
396 perror ("VIDIOC_QUERYCTRL");
397 exit (EXIT_FAILURE);
398 }
399}
400</programlisting>
401 </example>
402
403 <example>
404 <title>Changing controls</title>
405
406 <programlisting>
407&v4l2-queryctrl; queryctrl;
408&v4l2-control; control;
409
410memset (&amp;queryctrl, 0, sizeof (queryctrl));
411queryctrl.id = V4L2_CID_BRIGHTNESS;
412
413if (-1 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;queryctrl)) {
414 if (errno != EINVAL) {
415 perror ("VIDIOC_QUERYCTRL");
416 exit (EXIT_FAILURE);
417 } else {
418 printf ("V4L2_CID_BRIGHTNESS is not supported\n");
419 }
420} else if (queryctrl.flags &amp; V4L2_CTRL_FLAG_DISABLED) {
421 printf ("V4L2_CID_BRIGHTNESS is not supported\n");
422} else {
423 memset (&amp;control, 0, sizeof (control));
424 control.id = V4L2_CID_BRIGHTNESS;
425 control.value = queryctrl.default_value;
426
427 if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &amp;control)) {
428 perror ("VIDIOC_S_CTRL");
429 exit (EXIT_FAILURE);
430 }
431}
432
433memset (&amp;control, 0, sizeof (control));
434control.id = V4L2_CID_CONTRAST;
435
436if (0 == ioctl (fd, &VIDIOC-G-CTRL;, &amp;control)) {
437 control.value += 1;
438
439 /* The driver may clamp the value or return ERANGE, ignored here */
440
441 if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &amp;control)
442 &amp;&amp; errno != ERANGE) {
443 perror ("VIDIOC_S_CTRL");
444 exit (EXIT_FAILURE);
445 }
446/* Ignore if V4L2_CID_CONTRAST is unsupported */
447} else if (errno != EINVAL) {
448 perror ("VIDIOC_G_CTRL");
449 exit (EXIT_FAILURE);
450}
451
452control.id = V4L2_CID_AUDIO_MUTE;
453control.value = TRUE; /* silence */
454
455/* Errors ignored */
456ioctl (fd, VIDIOC_S_CTRL, &amp;control);
457</programlisting>
458 </example>
459 </section>
460
461 <section id="extended-controls">
462 <title>Extended Controls</title>
463
464 <section>
465 <title>Introduction</title>
466
467 <para>The control mechanism as originally designed was meant
468to be used for user settings (brightness, saturation, etc). However,
469it turned out to be a very useful model for implementing more
470complicated driver APIs where each driver implements only a subset of
471a larger API.</para>
472
473 <para>The MPEG encoding API was the driving force behind
474designing and implementing this extended control mechanism: the MPEG
475standard is quite large and the currently supported hardware MPEG
476encoders each only implement a subset of this standard. Further more,
477many parameters relating to how the video is encoded into an MPEG
478stream are specific to the MPEG encoding chip since the MPEG standard
479only defines the format of the resulting MPEG stream, not how the
480video is actually encoded into that format.</para>
481
482 <para>Unfortunately, the original control API lacked some
483features needed for these new uses and so it was extended into the
484(not terribly originally named) extended control API.</para>
485
486 <para>Even though the MPEG encoding API was the first effort
487to use the Extended Control API, nowadays there are also other classes
488of Extended Controls, such as Camera Controls and FM Transmitter Controls.
489The Extended Controls API as well as all Extended Controls classes are
490described in the following text.</para>
491 </section>
492
493 <section>
494 <title>The Extended Control API</title>
495
496 <para>Three new ioctls are available: &VIDIOC-G-EXT-CTRLS;,
497&VIDIOC-S-EXT-CTRLS; and &VIDIOC-TRY-EXT-CTRLS;. These ioctls act on
498arrays of controls (as opposed to the &VIDIOC-G-CTRL; and
499&VIDIOC-S-CTRL; ioctls that act on a single control). This is needed
500since it is often required to atomically change several controls at
501once.</para>
502
503 <para>Each of the new ioctls expects a pointer to a
504&v4l2-ext-controls;. This structure contains a pointer to the control
505array, a count of the number of controls in that array and a control
506class. Control classes are used to group similar controls into a
507single class. For example, control class
508<constant>V4L2_CTRL_CLASS_USER</constant> contains all user controls
509(&ie; all controls that can also be set using the old
510<constant>VIDIOC_S_CTRL</constant> ioctl). Control class
511<constant>V4L2_CTRL_CLASS_MPEG</constant> contains all controls
512relating to MPEG encoding, etc.</para>
513
514 <para>All controls in the control array must belong to the
515specified control class. An error is returned if this is not the
516case.</para>
517
518 <para>It is also possible to use an empty control array (count
519== 0) to check whether the specified control class is
520supported.</para>
521
522 <para>The control array is a &v4l2-ext-control; array. The
523<structname>v4l2_ext_control</structname> structure is very similar to
524&v4l2-control;, except for the fact that it also allows for 64-bit
525values and pointers to be passed.</para>
526
527 <para>It is important to realize that due to the flexibility of
528controls it is necessary to check whether the control you want to set
529actually is supported in the driver and what the valid range of values
530is. So use the &VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls to
531check this. Also note that it is possible that some of the menu
532indices in a control of type <constant>V4L2_CTRL_TYPE_MENU</constant>
533may not be supported (<constant>VIDIOC_QUERYMENU</constant> will
534return an error). A good example is the list of supported MPEG audio
535bitrates. Some drivers only support one or two bitrates, others
536support a wider range.</para>
537 </section>
538
539 <section>
540 <title>Enumerating Extended Controls</title>
541
542 <para>The recommended way to enumerate over the extended
543controls is by using &VIDIOC-QUERYCTRL; in combination with the
544<constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> flag:</para>
545
546 <informalexample>
547 <programlisting>
548&v4l2-queryctrl; qctrl;
549
550qctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL;
551while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;qctrl)) {
552 /* ... */
553 qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
554}
555</programlisting>
556 </informalexample>
557
558 <para>The initial control ID is set to 0 ORed with the
559<constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> flag. The
560<constant>VIDIOC_QUERYCTRL</constant> ioctl will return the first
561control with a higher ID than the specified one. When no such controls
562are found an error is returned.</para>
563
564 <para>If you want to get all controls within a specific control
565class, then you can set the initial
566<structfield>qctrl.id</structfield> value to the control class and add
567an extra check to break out of the loop when a control of another
568control class is found:</para>
569
570 <informalexample>
571 <programlisting>
572qctrl.id = V4L2_CTRL_CLASS_MPEG | V4L2_CTRL_FLAG_NEXT_CTRL;
573while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &amp;qctrl)) {
574 if (V4L2_CTRL_ID2CLASS (qctrl.id) != V4L2_CTRL_CLASS_MPEG)
575 break;
576 /* ... */
577 qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
578 }
579</programlisting>
580 </informalexample>
581
582 <para>The 32-bit <structfield>qctrl.id</structfield> value is
583subdivided into three bit ranges: the top 4 bits are reserved for
584flags (&eg; <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant>) and are not
585actually part of the ID. The remaining 28 bits form the control ID, of
586which the most significant 12 bits define the control class and the
587least significant 16 bits identify the control within the control
588class. It is guaranteed that these last 16 bits are always non-zero
589for controls. The range of 0x1000 and up are reserved for
590driver-specific controls. The macro
591<constant>V4L2_CTRL_ID2CLASS(id)</constant> returns the control class
592ID based on a control ID.</para>
593
594 <para>If the driver does not support extended controls, then
595<constant>VIDIOC_QUERYCTRL</constant> will fail when used in
596combination with <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant>. In
597that case the old method of enumerating control should be used (see
5981.8). But if it is supported, then it is guaranteed to enumerate over
599all controls, including driver-private controls.</para>
600 </section>
601
602 <section>
603 <title>Creating Control Panels</title>
604
605 <para>It is possible to create control panels for a graphical
606user interface where the user can select the various controls.
607Basically you will have to iterate over all controls using the method
608described above. Each control class starts with a control of type
609<constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant>.
610<constant>VIDIOC_QUERYCTRL</constant> will return the name of this
611control class which can be used as the title of a tab page within a
612control panel.</para>
613
614 <para>The flags field of &v4l2-queryctrl; also contains hints on
615the behavior of the control. See the &VIDIOC-QUERYCTRL; documentation
616for more details.</para>
617 </section>
618
619 <section id="mpeg-controls">
620 <title>MPEG Control Reference</title>
621
622 <para>Below all controls within the MPEG control class are
623described. First the generic controls, then controls specific for
624certain hardware.</para>
625
626 <section>
627 <title>Generic MPEG Controls</title>
628
629 <table pgwide="1" frame="none" id="mpeg-control-id">
630 <title>MPEG Control IDs</title>
631 <tgroup cols="4">
632 <colspec colname="c1" colwidth="1*" />
633 <colspec colname="c2" colwidth="6*" />
634 <colspec colname="c3" colwidth="2*" />
635 <colspec colname="c4" colwidth="6*" />
636 <spanspec namest="c1" nameend="c2" spanname="id" />
637 <spanspec namest="c2" nameend="c4" spanname="descr" />
638 <thead>
639 <row>
640 <entry spanname="id" align="left">ID</entry>
641 <entry align="left">Type</entry>
642 </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
643 </row>
644 </thead>
645 <tbody valign="top">
646 <row><entry></entry></row>
647 <row>
648 <entry spanname="id"><constant>V4L2_CID_MPEG_CLASS</constant>&nbsp;</entry>
649 <entry>class</entry>
650 </row><row><entry spanname="descr">The MPEG class
651descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a
652description of this control class. This description can be used as the
653caption of a Tab page in a GUI, for example.</entry>
654 </row>
655 <row><entry></entry></row>
656 <row id="v4l2-mpeg-stream-type">
657 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_TYPE</constant>&nbsp;</entry>
658 <entry>enum&nbsp;v4l2_mpeg_stream_type</entry>
659 </row><row><entry spanname="descr">The MPEG-1, -2 or -4
660output stream type. One cannot assume anything here. Each hardware
661MPEG encoder tends to support different subsets of the available MPEG
662stream types. The currently defined stream types are:</entry>
663 </row>
664 <row>
665 <entrytbl spanname="descr" cols="2">
666 <tbody valign="top">
667 <row>
668 <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_PS</constant>&nbsp;</entry>
669 <entry>MPEG-2 program stream</entry>
670 </row>
671 <row>
672 <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_TS</constant>&nbsp;</entry>
673 <entry>MPEG-2 transport stream</entry>
674 </row>
675 <row>
676 <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG1_SS</constant>&nbsp;</entry>
677 <entry>MPEG-1 system stream</entry>
678 </row>
679 <row>
680 <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_DVD</constant>&nbsp;</entry>
681 <entry>MPEG-2 DVD-compatible stream</entry>
682 </row>
683 <row>
684 <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG1_VCD</constant>&nbsp;</entry>
685 <entry>MPEG-1 VCD-compatible stream</entry>
686 </row>
687 <row>
688 <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_SVCD</constant>&nbsp;</entry>
689 <entry>MPEG-2 SVCD-compatible stream</entry>
690 </row>
691 </tbody>
692 </entrytbl>
693 </row>
694 <row><entry></entry></row>
695 <row>
696 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_PMT</constant>&nbsp;</entry>
697 <entry>integer</entry>
698 </row><row><entry spanname="descr">Program Map Table
699Packet ID for the MPEG transport stream (default 16)</entry>
700 </row>
701 <row><entry></entry></row>
702 <row>
703 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_AUDIO</constant>&nbsp;</entry>
704 <entry>integer</entry>
705 </row><row><entry spanname="descr">Audio Packet ID for
706the MPEG transport stream (default 256)</entry>
707 </row>
708 <row><entry></entry></row>
709 <row>
710 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_VIDEO</constant>&nbsp;</entry>
711 <entry>integer</entry>
712 </row><row><entry spanname="descr">Video Packet ID for
713the MPEG transport stream (default 260)</entry>
714 </row>
715 <row><entry></entry></row>
716 <row>
717 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_PCR</constant>&nbsp;</entry>
718 <entry>integer</entry>
719 </row><row><entry spanname="descr">Packet ID for the
720MPEG transport stream carrying PCR fields (default 259)</entry>
721 </row>
722 <row><entry></entry></row>
723 <row>
724 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PES_ID_AUDIO</constant>&nbsp;</entry>
725 <entry>integer</entry>
726 </row><row><entry spanname="descr">Audio ID for MPEG
727PES</entry>
728 </row>
729 <row><entry></entry></row>
730 <row>
731 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PES_ID_VIDEO</constant>&nbsp;</entry>
732 <entry>integer</entry>
733 </row><row><entry spanname="descr">Video ID for MPEG
734PES</entry>
735 </row>
736 <row><entry></entry></row>
737 <row id="v4l2-mpeg-stream-vbi-fmt">
738 <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_VBI_FMT</constant>&nbsp;</entry>
739 <entry>enum&nbsp;v4l2_mpeg_stream_vbi_fmt</entry>
740 </row><row><entry spanname="descr">Some cards can embed
741VBI data (&eg; Closed Caption, Teletext) into the MPEG stream. This
742control selects whether VBI data should be embedded, and if so, what
743embedding method should be used. The list of possible VBI formats
744depends on the driver. The currently defined VBI format types
745are:</entry>
746 </row>
747 <row>
748 <entrytbl spanname="descr" cols="2">
749 <tbody valign="top">
750 <row>
751 <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_NONE</constant>&nbsp;</entry>
752 <entry>No VBI in the MPEG stream</entry>
753 </row>
754 <row>
755 <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_IVTV</constant>&nbsp;</entry>
756 <entry>VBI in private packets, IVTV format (documented
757in the kernel sources in the file <filename>Documentation/video4linux/cx2341x/README.vbi</filename>)</entry>
758 </row>
759 </tbody>
760 </entrytbl>
761 </row>
762 <row><entry></entry></row>
763 <row id="v4l2-mpeg-audio-sampling-freq">
764 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ</constant>&nbsp;</entry>
765 <entry>enum&nbsp;v4l2_mpeg_audio_sampling_freq</entry>
766 </row><row><entry spanname="descr">MPEG Audio sampling
767frequency. Possible values are:</entry>
768 </row>
769 <row>
770 <entrytbl spanname="descr" cols="2">
771 <tbody valign="top">
772 <row>
773 <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_44100</constant>&nbsp;</entry>
774 <entry>44.1 kHz</entry>
775 </row>
776 <row>
777 <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_48000</constant>&nbsp;</entry>
778 <entry>48 kHz</entry>
779 </row>
780 <row>
781 <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_32000</constant>&nbsp;</entry>
782 <entry>32 kHz</entry>
783 </row>
784 </tbody>
785 </entrytbl>
786 </row>
787 <row><entry></entry></row>
788 <row id="v4l2-mpeg-audio-encoding">
789 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_ENCODING</constant>&nbsp;</entry>
790 <entry>enum&nbsp;v4l2_mpeg_audio_encoding</entry>
791 </row><row><entry spanname="descr">MPEG Audio encoding.
792Possible values are:</entry>
793 </row>
794 <row>
795 <entrytbl spanname="descr" cols="2">
796 <tbody valign="top">
797 <row>
798 <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_1</constant>&nbsp;</entry>
799 <entry>MPEG-1/2 Layer I encoding</entry>
800 </row>
801 <row>
802 <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_2</constant>&nbsp;</entry>
803 <entry>MPEG-1/2 Layer II encoding</entry>
804 </row>
805 <row>
806 <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_3</constant>&nbsp;</entry>
807 <entry>MPEG-1/2 Layer III encoding</entry>
808 </row>
809 <row>
810 <entry><constant>V4L2_MPEG_AUDIO_ENCODING_AAC</constant>&nbsp;</entry>
811 <entry>MPEG-2/4 AAC (Advanced Audio Coding)</entry>
812 </row>
813 <row>
814 <entry><constant>V4L2_MPEG_AUDIO_ENCODING_AC3</constant>&nbsp;</entry>
815 <entry>AC-3 aka ATSC A/52 encoding</entry>
816 </row>
817 </tbody>
818 </entrytbl>
819 </row>
820 <row><entry></entry></row>
821 <row id="v4l2-mpeg-audio-l1-bitrate">
822 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L1_BITRATE</constant>&nbsp;</entry>
823 <entry>enum&nbsp;v4l2_mpeg_audio_l1_bitrate</entry>
824 </row><row><entry spanname="descr">MPEG-1/2 Layer I bitrate.
825Possible values are:</entry>
826 </row>
827 <row>
828 <entrytbl spanname="descr" cols="2">
829 <tbody valign="top">
830 <row>
831 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_32K</constant>&nbsp;</entry>
832 <entry>32 kbit/s</entry></row>
833 <row>
834 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_64K</constant>&nbsp;</entry>
835 <entry>64 kbit/s</entry>
836 </row>
837 <row>
838 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_96K</constant>&nbsp;</entry>
839 <entry>96 kbit/s</entry>
840 </row>
841 <row>
842 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_128K</constant>&nbsp;</entry>
843 <entry>128 kbit/s</entry>
844 </row>
845 <row>
846 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_160K</constant>&nbsp;</entry>
847 <entry>160 kbit/s</entry>
848 </row>
849 <row>
850 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_192K</constant>&nbsp;</entry>
851 <entry>192 kbit/s</entry>
852 </row>
853 <row>
854 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_224K</constant>&nbsp;</entry>
855 <entry>224 kbit/s</entry>
856 </row>
857 <row>
858 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_256K</constant>&nbsp;</entry>
859 <entry>256 kbit/s</entry>
860 </row>
861 <row>
862 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_288K</constant>&nbsp;</entry>
863 <entry>288 kbit/s</entry>
864 </row>
865 <row>
866 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_320K</constant>&nbsp;</entry>
867 <entry>320 kbit/s</entry>
868 </row>
869 <row>
870 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_352K</constant>&nbsp;</entry>
871 <entry>352 kbit/s</entry>
872 </row>
873 <row>
874 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_384K</constant>&nbsp;</entry>
875 <entry>384 kbit/s</entry>
876 </row>
877 <row>
878 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_416K</constant>&nbsp;</entry>
879 <entry>416 kbit/s</entry>
880 </row>
881 <row>
882 <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_448K</constant>&nbsp;</entry>
883 <entry>448 kbit/s</entry>
884 </row>
885 </tbody>
886 </entrytbl>
887 </row>
888 <row><entry></entry></row>
889 <row id="v4l2-mpeg-audio-l2-bitrate">
890 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L2_BITRATE</constant>&nbsp;</entry>
891 <entry>enum&nbsp;v4l2_mpeg_audio_l2_bitrate</entry>
892 </row><row><entry spanname="descr">MPEG-1/2 Layer II bitrate.
893Possible values are:</entry>
894 </row>
895 <row>
896 <entrytbl spanname="descr" cols="2">
897 <tbody valign="top">
898 <row>
899 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_32K</constant>&nbsp;</entry>
900 <entry>32 kbit/s</entry>
901 </row>
902 <row>
903 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_48K</constant>&nbsp;</entry>
904 <entry>48 kbit/s</entry>
905 </row>
906 <row>
907 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_56K</constant>&nbsp;</entry>
908 <entry>56 kbit/s</entry>
909 </row>
910 <row>
911 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_64K</constant>&nbsp;</entry>
912 <entry>64 kbit/s</entry>
913 </row>
914 <row>
915 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_80K</constant>&nbsp;</entry>
916 <entry>80 kbit/s</entry>
917 </row>
918 <row>
919 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_96K</constant>&nbsp;</entry>
920 <entry>96 kbit/s</entry>
921 </row>
922 <row>
923 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_112K</constant>&nbsp;</entry>
924 <entry>112 kbit/s</entry>
925 </row>
926 <row>
927 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_128K</constant>&nbsp;</entry>
928 <entry>128 kbit/s</entry>
929 </row>
930 <row>
931 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_160K</constant>&nbsp;</entry>
932 <entry>160 kbit/s</entry>
933 </row>
934 <row>
935 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_192K</constant>&nbsp;</entry>
936 <entry>192 kbit/s</entry>
937 </row>
938 <row>
939 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_224K</constant>&nbsp;</entry>
940 <entry>224 kbit/s</entry>
941 </row>
942 <row>
943 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_256K</constant>&nbsp;</entry>
944 <entry>256 kbit/s</entry>
945 </row>
946 <row>
947 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_320K</constant>&nbsp;</entry>
948 <entry>320 kbit/s</entry>
949 </row>
950 <row>
951 <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_384K</constant>&nbsp;</entry>
952 <entry>384 kbit/s</entry>
953 </row>
954 </tbody>
955 </entrytbl>
956 </row>
957 <row><entry></entry></row>
958 <row id="v4l2-mpeg-audio-l3-bitrate">
959 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L3_BITRATE</constant>&nbsp;</entry>
960 <entry>enum&nbsp;v4l2_mpeg_audio_l3_bitrate</entry>
961 </row><row><entry spanname="descr">MPEG-1/2 Layer III bitrate.
962Possible values are:</entry>
963 </row>
964 <row>
965 <entrytbl spanname="descr" cols="2">
966 <tbody valign="top">
967 <row>
968 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_32K</constant>&nbsp;</entry>
969 <entry>32 kbit/s</entry>
970 </row>
971 <row>
972 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_40K</constant>&nbsp;</entry>
973 <entry>40 kbit/s</entry>
974 </row>
975 <row>
976 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_48K</constant>&nbsp;</entry>
977 <entry>48 kbit/s</entry>
978 </row>
979 <row>
980 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_56K</constant>&nbsp;</entry>
981 <entry>56 kbit/s</entry>
982 </row>
983 <row>
984 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_64K</constant>&nbsp;</entry>
985 <entry>64 kbit/s</entry>
986 </row>
987 <row>
988 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_80K</constant>&nbsp;</entry>
989 <entry>80 kbit/s</entry>
990 </row>
991 <row>
992 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_96K</constant>&nbsp;</entry>
993 <entry>96 kbit/s</entry>
994 </row>
995 <row>
996 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_112K</constant>&nbsp;</entry>
997 <entry>112 kbit/s</entry>
998 </row>
999 <row>
1000 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_128K</constant>&nbsp;</entry>
1001 <entry>128 kbit/s</entry>
1002 </row>
1003 <row>
1004 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_160K</constant>&nbsp;</entry>
1005 <entry>160 kbit/s</entry>
1006 </row>
1007 <row>
1008 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_192K</constant>&nbsp;</entry>
1009 <entry>192 kbit/s</entry>
1010 </row>
1011 <row>
1012 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_224K</constant>&nbsp;</entry>
1013 <entry>224 kbit/s</entry>
1014 </row>
1015 <row>
1016 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_256K</constant>&nbsp;</entry>
1017 <entry>256 kbit/s</entry>
1018 </row>
1019 <row>
1020 <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_320K</constant>&nbsp;</entry>
1021 <entry>320 kbit/s</entry>
1022 </row>
1023 </tbody>
1024 </entrytbl>
1025 </row>
1026 <row><entry></entry></row>
1027 <row>
1028 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_AAC_BITRATE</constant>&nbsp;</entry>
1029 <entry>integer</entry>
1030 </row><row><entry spanname="descr">AAC bitrate in bits per second.</entry>
1031 </row>
1032 <row><entry></entry></row>
1033 <row id="v4l2-mpeg-audio-ac3-bitrate">
1034 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_AC3_BITRATE</constant>&nbsp;</entry>
1035 <entry>enum&nbsp;v4l2_mpeg_audio_ac3_bitrate</entry>
1036 </row><row><entry spanname="descr">AC-3 bitrate.
1037Possible values are:</entry>
1038 </row>
1039 <row>
1040 <entrytbl spanname="descr" cols="2">
1041 <tbody valign="top">
1042 <row>
1043 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_32K</constant>&nbsp;</entry>
1044 <entry>32 kbit/s</entry>
1045 </row>
1046 <row>
1047 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_40K</constant>&nbsp;</entry>
1048 <entry>40 kbit/s</entry>
1049 </row>
1050 <row>
1051 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_48K</constant>&nbsp;</entry>
1052 <entry>48 kbit/s</entry>
1053 </row>
1054 <row>
1055 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_56K</constant>&nbsp;</entry>
1056 <entry>56 kbit/s</entry>
1057 </row>
1058 <row>
1059 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_64K</constant>&nbsp;</entry>
1060 <entry>64 kbit/s</entry>
1061 </row>
1062 <row>
1063 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_80K</constant>&nbsp;</entry>
1064 <entry>80 kbit/s</entry>
1065 </row>
1066 <row>
1067 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_96K</constant>&nbsp;</entry>
1068 <entry>96 kbit/s</entry>
1069 </row>
1070 <row>
1071 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_112K</constant>&nbsp;</entry>
1072 <entry>112 kbit/s</entry>
1073 </row>
1074 <row>
1075 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_128K</constant>&nbsp;</entry>
1076 <entry>128 kbit/s</entry>
1077 </row>
1078 <row>
1079 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_160K</constant>&nbsp;</entry>
1080 <entry>160 kbit/s</entry>
1081 </row>
1082 <row>
1083 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_192K</constant>&nbsp;</entry>
1084 <entry>192 kbit/s</entry>
1085 </row>
1086 <row>
1087 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_224K</constant>&nbsp;</entry>
1088 <entry>224 kbit/s</entry>
1089 </row>
1090 <row>
1091 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_256K</constant>&nbsp;</entry>
1092 <entry>256 kbit/s</entry>
1093 </row>
1094 <row>
1095 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_320K</constant>&nbsp;</entry>
1096 <entry>320 kbit/s</entry>
1097 </row>
1098 <row>
1099 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_384K</constant>&nbsp;</entry>
1100 <entry>384 kbit/s</entry>
1101 </row>
1102 <row>
1103 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_448K</constant>&nbsp;</entry>
1104 <entry>448 kbit/s</entry>
1105 </row>
1106 <row>
1107 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_512K</constant>&nbsp;</entry>
1108 <entry>512 kbit/s</entry>
1109 </row>
1110 <row>
1111 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_576K</constant>&nbsp;</entry>
1112 <entry>576 kbit/s</entry>
1113 </row>
1114 <row>
1115 <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_640K</constant>&nbsp;</entry>
1116 <entry>640 kbit/s</entry>
1117 </row>
1118 </tbody>
1119 </entrytbl>
1120 </row>
1121 <row><entry></entry></row>
1122 <row id="v4l2-mpeg-audio-mode">
1123 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MODE</constant>&nbsp;</entry>
1124 <entry>enum&nbsp;v4l2_mpeg_audio_mode</entry>
1125 </row><row><entry spanname="descr">MPEG Audio mode.
1126Possible values are:</entry>
1127 </row>
1128 <row>
1129 <entrytbl spanname="descr" cols="2">
1130 <tbody valign="top">
1131 <row>
1132 <entry><constant>V4L2_MPEG_AUDIO_MODE_STEREO</constant>&nbsp;</entry>
1133 <entry>Stereo</entry>
1134 </row>
1135 <row>
1136 <entry><constant>V4L2_MPEG_AUDIO_MODE_JOINT_STEREO</constant>&nbsp;</entry>
1137 <entry>Joint Stereo</entry>
1138 </row>
1139 <row>
1140 <entry><constant>V4L2_MPEG_AUDIO_MODE_DUAL</constant>&nbsp;</entry>
1141 <entry>Bilingual</entry>
1142 </row>
1143 <row>
1144 <entry><constant>V4L2_MPEG_AUDIO_MODE_MONO</constant>&nbsp;</entry>
1145 <entry>Mono</entry>
1146 </row>
1147 </tbody>
1148 </entrytbl>
1149 </row>
1150 <row><entry></entry></row>
1151 <row id="v4l2-mpeg-audio-mode-extension">
1152 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MODE_EXTENSION</constant>&nbsp;</entry>
1153 <entry>enum&nbsp;v4l2_mpeg_audio_mode_extension</entry>
1154 </row><row><entry spanname="descr">Joint Stereo
1155audio mode extension. In Layer I and II they indicate which subbands
1156are in intensity stereo. All other subbands are coded in stereo. Layer
1157III is not (yet) supported. Possible values
1158are:</entry>
1159 </row>
1160 <row>
1161 <entrytbl spanname="descr" cols="2">
1162 <tbody valign="top">
1163 <row>
1164 <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_4</constant>&nbsp;</entry>
1165 <entry>Subbands 4-31 in intensity stereo</entry>
1166 </row>
1167 <row>
1168 <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_8</constant>&nbsp;</entry>
1169 <entry>Subbands 8-31 in intensity stereo</entry>
1170 </row>
1171 <row>
1172 <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_12</constant>&nbsp;</entry>
1173 <entry>Subbands 12-31 in intensity stereo</entry>
1174 </row>
1175 <row>
1176 <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_16</constant>&nbsp;</entry>
1177 <entry>Subbands 16-31 in intensity stereo</entry>
1178 </row>
1179 </tbody>
1180 </entrytbl>
1181 </row>
1182 <row><entry></entry></row>
1183 <row id="v4l2-mpeg-audio-emphasis">
1184 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_EMPHASIS</constant>&nbsp;</entry>
1185 <entry>enum&nbsp;v4l2_mpeg_audio_emphasis</entry>
1186 </row><row><entry spanname="descr">Audio Emphasis.
1187Possible values are:</entry>
1188 </row>
1189 <row>
1190 <entrytbl spanname="descr" cols="2">
1191 <tbody valign="top">
1192 <row>
1193 <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_NONE</constant>&nbsp;</entry>
1194 <entry>None</entry>
1195 </row>
1196 <row>
1197 <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_50_DIV_15_uS</constant>&nbsp;</entry>
1198 <entry>50/15 microsecond emphasis</entry>
1199 </row>
1200 <row>
1201 <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_CCITT_J17</constant>&nbsp;</entry>
1202 <entry>CCITT J.17</entry>
1203 </row>
1204 </tbody>
1205 </entrytbl>
1206 </row>
1207 <row><entry></entry></row>
1208 <row id="v4l2-mpeg-audio-crc">
1209 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_CRC</constant>&nbsp;</entry>
1210 <entry>enum&nbsp;v4l2_mpeg_audio_crc</entry>
1211 </row><row><entry spanname="descr">CRC method. Possible
1212values are:</entry>
1213 </row>
1214 <row>
1215 <entrytbl spanname="descr" cols="2">
1216 <tbody valign="top">
1217 <row>
1218 <entry><constant>V4L2_MPEG_AUDIO_CRC_NONE</constant>&nbsp;</entry>
1219 <entry>None</entry>
1220 </row>
1221 <row>
1222 <entry><constant>V4L2_MPEG_AUDIO_CRC_CRC16</constant>&nbsp;</entry>
1223 <entry>16 bit parity check</entry>
1224 </row>
1225 </tbody>
1226 </entrytbl>
1227 </row>
1228 <row><entry></entry></row>
1229 <row>
1230 <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MUTE</constant>&nbsp;</entry>
1231 <entry>boolean</entry>
1232 </row><row><entry spanname="descr">Mutes the audio when
1233capturing. This is not done by muting audio hardware, which can still
1234produce a slight hiss, but in the encoder itself, guaranteeing a fixed
1235and reproducable audio bitstream. 0 = unmuted, 1 = muted.</entry>
1236 </row>
1237 <row><entry></entry></row>
1238 <row id="v4l2-mpeg-video-encoding">
1239 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_ENCODING</constant>&nbsp;</entry>
1240 <entry>enum&nbsp;v4l2_mpeg_video_encoding</entry>
1241 </row><row><entry spanname="descr">MPEG Video encoding
1242method. Possible values are:</entry>
1243 </row>
1244 <row>
1245 <entrytbl spanname="descr" cols="2">
1246 <tbody valign="top">
1247 <row>
1248 <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_1</constant>&nbsp;</entry>
1249 <entry>MPEG-1 Video encoding</entry>
1250 </row>
1251 <row>
1252 <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_2</constant>&nbsp;</entry>
1253 <entry>MPEG-2 Video encoding</entry>
1254 </row>
1255 <row>
1256 <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC</constant>&nbsp;</entry>
1257 <entry>MPEG-4 AVC (H.264) Video encoding</entry>
1258 </row>
1259 </tbody>
1260 </entrytbl>
1261 </row>
1262 <row><entry></entry></row>
1263 <row id="v4l2-mpeg-video-aspect">
1264 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_ASPECT</constant>&nbsp;</entry>
1265 <entry>enum&nbsp;v4l2_mpeg_video_aspect</entry>
1266 </row><row><entry spanname="descr">Video aspect.
1267Possible values are:</entry>
1268 </row>
1269 <row>
1270 <entrytbl spanname="descr" cols="2">
1271 <tbody valign="top">
1272 <row>
1273 <entry><constant>V4L2_MPEG_VIDEO_ASPECT_1x1</constant>&nbsp;</entry>
1274 </row>
1275 <row>
1276 <entry><constant>V4L2_MPEG_VIDEO_ASPECT_4x3</constant>&nbsp;</entry>
1277 </row>
1278 <row>
1279 <entry><constant>V4L2_MPEG_VIDEO_ASPECT_16x9</constant>&nbsp;</entry>
1280 </row>
1281 <row>
1282 <entry><constant>V4L2_MPEG_VIDEO_ASPECT_221x100</constant>&nbsp;</entry>
1283 </row>
1284 </tbody>
1285 </entrytbl>
1286 </row>
1287 <row><entry></entry></row>
1288 <row>
1289 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_B_FRAMES</constant>&nbsp;</entry>
1290 <entry>integer</entry>
1291 </row><row><entry spanname="descr">Number of B-Frames
1292(default 2)</entry>
1293 </row>
1294 <row><entry></entry></row>
1295 <row>
1296 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_GOP_SIZE</constant>&nbsp;</entry>
1297 <entry>integer</entry>
1298 </row><row><entry spanname="descr">GOP size (default
129912)</entry>
1300 </row>
1301 <row><entry></entry></row>
1302 <row>
1303 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_GOP_CLOSURE</constant>&nbsp;</entry>
1304 <entry>boolean</entry>
1305 </row><row><entry spanname="descr">GOP closure (default
13061)</entry>
1307 </row>
1308 <row><entry></entry></row>
1309 <row>
1310 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_PULLDOWN</constant>&nbsp;</entry>
1311 <entry>boolean</entry>
1312 </row><row><entry spanname="descr">Enable 3:2 pulldown
1313(default 0)</entry>
1314 </row>
1315 <row><entry></entry></row>
1316 <row id="v4l2-mpeg-video-bitrate-mode">
1317 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE_MODE</constant>&nbsp;</entry>
1318 <entry>enum&nbsp;v4l2_mpeg_video_bitrate_mode</entry>
1319 </row><row><entry spanname="descr">Video bitrate mode.
1320Possible values are:</entry>
1321 </row>
1322 <row>
1323 <entrytbl spanname="descr" cols="2">
1324 <tbody valign="top">
1325 <row>
1326 <entry><constant>V4L2_MPEG_VIDEO_BITRATE_MODE_VBR</constant>&nbsp;</entry>
1327 <entry>Variable bitrate</entry>
1328 </row>
1329 <row>
1330 <entry><constant>V4L2_MPEG_VIDEO_BITRATE_MODE_CBR</constant>&nbsp;</entry>
1331 <entry>Constant bitrate</entry>
1332 </row>
1333 </tbody>
1334 </entrytbl>
1335 </row>
1336 <row><entry></entry></row>
1337 <row>
1338 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE</constant>&nbsp;</entry>
1339 <entry>integer</entry>
1340 </row><row><entry spanname="descr">Video bitrate in bits
1341per second.</entry>
1342 </row>
1343 <row><entry></entry></row>
1344 <row>
1345 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE_PEAK</constant>&nbsp;</entry>
1346 <entry>integer</entry>
1347 </row><row><entry spanname="descr">Peak video bitrate in
1348bits per second. Must be larger or equal to the average video bitrate.
1349It is ignored if the video bitrate mode is set to constant
1350bitrate.</entry>
1351 </row>
1352 <row><entry></entry></row>
1353 <row>
1354 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION</constant>&nbsp;</entry>
1355 <entry>integer</entry>
1356 </row><row><entry spanname="descr">For every captured
1357frame, skip this many subsequent frames (default 0).</entry>
1358 </row>
1359 <row><entry></entry></row>
1360 <row>
1361 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MUTE</constant>&nbsp;</entry>
1362 <entry>boolean</entry>
1363 </row>
1364 <row><entry spanname="descr">"Mutes" the video to a
1365fixed color when capturing. This is useful for testing, to produce a
1366fixed video bitstream. 0 = unmuted, 1 = muted.</entry>
1367 </row>
1368 <row><entry></entry></row>
1369 <row>
1370 <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MUTE_YUV</constant>&nbsp;</entry>
1371 <entry>integer</entry>
1372 </row><row><entry spanname="descr">Sets the "mute" color
1373of the video. The supplied 32-bit integer is interpreted as follows (bit
13740 = least significant bit):</entry>
1375 </row>
1376 <row>
1377 <entrytbl spanname="descr" cols="2">
1378 <tbody valign="top">
1379 <row>
1380 <entry>Bit 0:7</entry>
1381 <entry>V chrominance information</entry>
1382 </row>
1383 <row>
1384 <entry>Bit 8:15</entry>
1385 <entry>U chrominance information</entry>
1386 </row>
1387 <row>
1388 <entry>Bit 16:23</entry>
1389 <entry>Y luminance information</entry>
1390 </row>
1391 <row>
1392 <entry>Bit 24:31</entry>
1393 <entry>Must be zero.</entry>
1394 </row>
1395 </tbody>
1396 </entrytbl>
1397 </row>
1398 </tbody>
1399 </tgroup>
1400 </table>
1401 </section>
1402
1403 <section>
1404 <title>CX2341x MPEG Controls</title>
1405
1406 <para>The following MPEG class controls deal with MPEG
1407encoding settings that are specific to the Conexant CX23415 and
1408CX23416 MPEG encoding chips.</para>
1409
1410 <table pgwide="1" frame="none" id="cx2341x-control-id">
1411 <title>CX2341x Control IDs</title>
1412 <tgroup cols="4">
1413 <colspec colname="c1" colwidth="1*" />
1414 <colspec colname="c2" colwidth="6*" />
1415 <colspec colname="c3" colwidth="2*" />
1416 <colspec colname="c4" colwidth="6*" />
1417 <spanspec namest="c1" nameend="c2" spanname="id" />
1418 <spanspec namest="c2" nameend="c4" spanname="descr" />
1419 <thead>
1420 <row>
1421 <entry spanname="id" align="left">ID</entry>
1422 <entry align="left">Type</entry>
1423 </row><row><entry spanname="descr" align="left">Description</entry>
1424 </row>
1425 </thead>
1426 <tbody valign="top">
1427 <row><entry></entry></row>
1428 <row id="v4l2-mpeg-cx2341x-video-spatial-filter-mode">
1429 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE</constant>&nbsp;</entry>
1430 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_spatial_filter_mode</entry>
1431 </row><row><entry spanname="descr">Sets the Spatial
1432Filter mode (default <constant>MANUAL</constant>). Possible values
1433are:</entry>
1434 </row>
1435 <row>
1436 <entrytbl spanname="descr" cols="2">
1437 <tbody valign="top">
1438 <row>
1439 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_MANUAL</constant>&nbsp;</entry>
1440 <entry>Choose the filter manually</entry>
1441 </row>
1442 <row>
1443 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_AUTO</constant>&nbsp;</entry>
1444 <entry>Choose the filter automatically</entry>
1445 </row>
1446 </tbody>
1447 </entrytbl>
1448 </row>
1449 <row><entry></entry></row>
1450 <row>
1451 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER</constant>&nbsp;</entry>
1452 <entry>integer&nbsp;(0-15)</entry>
1453 </row><row><entry spanname="descr">The setting for the
1454Spatial Filter. 0 = off, 15 = maximum. (Default is 0.)</entry>
1455 </row>
1456 <row><entry></entry></row>
1457 <row id="luma-spatial-filter-type">
1458 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE</constant>&nbsp;</entry>
1459 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_luma_spatial_filter_type</entry>
1460 </row><row><entry spanname="descr">Select the algorithm
1461to use for the Luma Spatial Filter (default
1462<constant>1D_HOR</constant>). Possible values:</entry>
1463 </row>
1464 <row>
1465 <entrytbl spanname="descr" cols="2">
1466 <tbody valign="top">
1467 <row>
1468 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_OFF</constant>&nbsp;</entry>
1469 <entry>No filter</entry>
1470 </row>
1471 <row>
1472 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_HOR</constant>&nbsp;</entry>
1473 <entry>One-dimensional horizontal</entry>
1474 </row>
1475 <row>
1476 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_VERT</constant>&nbsp;</entry>
1477 <entry>One-dimensional vertical</entry>
1478 </row>
1479 <row>
1480 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_HV_SEPARABLE</constant>&nbsp;</entry>
1481 <entry>Two-dimensional separable</entry>
1482 </row>
1483 <row>
1484 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_SYM_NON_SEPARABLE</constant>&nbsp;</entry>
1485 <entry>Two-dimensional symmetrical
1486non-separable</entry>
1487 </row>
1488 </tbody>
1489 </entrytbl>
1490 </row>
1491 <row><entry></entry></row>
1492 <row id="chroma-spatial-filter-type">
1493 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE</constant>&nbsp;</entry>
1494 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_chroma_spatial_filter_type</entry>
1495 </row><row><entry spanname="descr">Select the algorithm
1496for the Chroma Spatial Filter (default <constant>1D_HOR</constant>).
1497Possible values are:</entry>
1498 </row>
1499 <row>
1500 <entrytbl spanname="descr" cols="2">
1501 <tbody valign="top">
1502 <row>
1503 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_OFF</constant>&nbsp;</entry>
1504 <entry>No filter</entry>
1505 </row>
1506 <row>
1507 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_1D_HOR</constant>&nbsp;</entry>
1508 <entry>One-dimensional horizontal</entry>
1509 </row>
1510 </tbody>
1511 </entrytbl>
1512 </row>
1513 <row><entry></entry></row>
1514 <row id="v4l2-mpeg-cx2341x-video-temporal-filter-mode">
1515 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE</constant>&nbsp;</entry>
1516 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_temporal_filter_mode</entry>
1517 </row><row><entry spanname="descr">Sets the Temporal
1518Filter mode (default <constant>MANUAL</constant>). Possible values
1519are:</entry>
1520 </row>
1521 <row>
1522 <entrytbl spanname="descr" cols="2">
1523 <tbody valign="top">
1524 <row>
1525 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_MANUAL</constant>&nbsp;</entry>
1526 <entry>Choose the filter manually</entry>
1527 </row>
1528 <row>
1529 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_AUTO</constant>&nbsp;</entry>
1530 <entry>Choose the filter automatically</entry>
1531 </row>
1532 </tbody>
1533 </entrytbl>
1534 </row>
1535 <row><entry></entry></row>
1536 <row>
1537 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER</constant>&nbsp;</entry>
1538 <entry>integer&nbsp;(0-31)</entry>
1539 </row><row><entry spanname="descr">The setting for the
1540Temporal Filter. 0 = off, 31 = maximum. (Default is 8 for full-scale
1541capturing and 0 for scaled capturing.)</entry>
1542 </row>
1543 <row><entry></entry></row>
1544 <row id="v4l2-mpeg-cx2341x-video-median-filter-type">
1545 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE</constant>&nbsp;</entry>
1546 <entry>enum&nbsp;v4l2_mpeg_cx2341x_video_median_filter_type</entry>
1547 </row><row><entry spanname="descr">Median Filter Type
1548(default <constant>OFF</constant>). Possible values are:</entry>
1549 </row>
1550 <row>
1551 <entrytbl spanname="descr" cols="2">
1552 <tbody valign="top">
1553 <row>
1554 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_OFF</constant>&nbsp;</entry>
1555 <entry>No filter</entry>
1556 </row>
1557 <row>
1558 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR</constant>&nbsp;</entry>
1559 <entry>Horizontal filter</entry>
1560 </row>
1561 <row>
1562 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_VERT</constant>&nbsp;</entry>
1563 <entry>Vertical filter</entry>
1564 </row>
1565 <row>
1566 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR_VERT</constant>&nbsp;</entry>
1567 <entry>Horizontal and vertical filter</entry>
1568 </row>
1569 <row>
1570 <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_DIAG</constant>&nbsp;</entry>
1571 <entry>Diagonal filter</entry>
1572 </row>
1573 </tbody>
1574 </entrytbl>
1575 </row>
1576 <row><entry></entry></row>
1577 <row>
1578 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_BOTTOM</constant>&nbsp;</entry>
1579 <entry>integer&nbsp;(0-255)</entry>
1580 </row><row><entry spanname="descr">Threshold above which
1581the luminance median filter is enabled (default 0)</entry>
1582 </row>
1583 <row><entry></entry></row>
1584 <row>
1585 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_TOP</constant>&nbsp;</entry>
1586 <entry>integer&nbsp;(0-255)</entry>
1587 </row><row><entry spanname="descr">Threshold below which
1588the luminance median filter is enabled (default 255)</entry>
1589 </row>
1590 <row><entry></entry></row>
1591 <row>
1592 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_BOTTOM</constant>&nbsp;</entry>
1593 <entry>integer&nbsp;(0-255)</entry>
1594 </row><row><entry spanname="descr">Threshold above which
1595the chroma median filter is enabled (default 0)</entry>
1596 </row>
1597 <row><entry></entry></row>
1598 <row>
1599 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_TOP</constant>&nbsp;</entry>
1600 <entry>integer&nbsp;(0-255)</entry>
1601 </row><row><entry spanname="descr">Threshold below which
1602the chroma median filter is enabled (default 255)</entry>
1603 </row>
1604 <row><entry></entry></row>
1605 <row>
1606 <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_STREAM_INSERT_NAV_PACKETS</constant>&nbsp;</entry>
1607 <entry>boolean</entry>
1608 </row>
1609 <row><entry spanname="descr">The CX2341X MPEG encoder
1610can insert one empty MPEG-2 PES packet into the stream between every
1611four video frames. The packet size is 2048 bytes, including the
1612packet_start_code_prefix and stream_id fields. The stream_id is 0xBF
1613(private stream 2). The payload consists of 0x00 bytes, to be filled
1614in by the application. 0 = do not insert, 1 = insert packets.</entry>
1615 </row>
1616 </tbody>
1617 </tgroup>
1618 </table>
1619 </section>
1620 </section>
1621
1622 <section id="camera-controls">
1623 <title>Camera Control Reference</title>
1624
1625 <para>The Camera class includes controls for mechanical (or
1626equivalent digital) features of a device such as controllable lenses
1627or sensors.</para>
1628
1629 <table pgwide="1" frame="none" id="camera-control-id">
1630 <title>Camera Control IDs</title>
1631 <tgroup cols="4">
1632 <colspec colname="c1" colwidth="1*" />
1633 <colspec colname="c2" colwidth="6*" />
1634 <colspec colname="c3" colwidth="2*" />
1635 <colspec colname="c4" colwidth="6*" />
1636 <spanspec namest="c1" nameend="c2" spanname="id" />
1637 <spanspec namest="c2" nameend="c4" spanname="descr" />
1638 <thead>
1639 <row>
1640 <entry spanname="id" align="left">ID</entry>
1641 <entry align="left">Type</entry>
1642 </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
1643 </row>
1644 </thead>
1645 <tbody valign="top">
1646 <row><entry></entry></row>
1647 <row>
1648 <entry spanname="id"><constant>V4L2_CID_CAMERA_CLASS</constant>&nbsp;</entry>
1649 <entry>class</entry>
1650 </row><row><entry spanname="descr">The Camera class
1651descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a
1652description of this control class.</entry>
1653 </row>
1654 <row><entry></entry></row>
1655
1656 <row id="v4l2-exposure-auto-type">
1657 <entry spanname="id"><constant>V4L2_CID_EXPOSURE_AUTO</constant>&nbsp;</entry>
1658 <entry>enum&nbsp;v4l2_exposure_auto_type</entry>
1659 </row><row><entry spanname="descr">Enables automatic
1660adjustments of the exposure time and/or iris aperture. The effect of
1661manual changes of the exposure time or iris aperture while these
1662features are enabled is undefined, drivers should ignore such
1663requests. Possible values are:</entry>
1664 </row>
1665 <row>
1666 <entrytbl spanname="descr" cols="2">
1667 <tbody valign="top">
1668 <row>
1669 <entry><constant>V4L2_EXPOSURE_AUTO</constant>&nbsp;</entry>
1670 <entry>Automatic exposure time, automatic iris
1671aperture.</entry>
1672 </row>
1673 <row>
1674 <entry><constant>V4L2_EXPOSURE_MANUAL</constant>&nbsp;</entry>
1675 <entry>Manual exposure time, manual iris.</entry>
1676 </row>
1677 <row>
1678 <entry><constant>V4L2_EXPOSURE_SHUTTER_PRIORITY</constant>&nbsp;</entry>
1679 <entry>Manual exposure time, auto iris.</entry>
1680 </row>
1681 <row>
1682 <entry><constant>V4L2_EXPOSURE_APERTURE_PRIORITY</constant>&nbsp;</entry>
1683 <entry>Auto exposure time, manual iris.</entry>
1684 </row>
1685 </tbody>
1686 </entrytbl>
1687 </row>
1688 <row><entry></entry></row>
1689
1690 <row>
1691 <entry spanname="id"><constant>V4L2_CID_EXPOSURE_ABSOLUTE</constant>&nbsp;</entry>
1692 <entry>integer</entry>
1693 </row><row><entry spanname="descr">Determines the exposure
1694time of the camera sensor. The exposure time is limited by the frame
1695interval. Drivers should interpret the values as 100 &micro;s units,
1696where the value 1 stands for 1/10000th of a second, 10000 for 1 second
1697and 100000 for 10 seconds.</entry>
1698 </row>
1699 <row><entry></entry></row>
1700
1701 <row>
1702 <entry spanname="id"><constant>V4L2_CID_EXPOSURE_AUTO_PRIORITY</constant>&nbsp;</entry>
1703 <entry>boolean</entry>
1704 </row><row><entry spanname="descr">When
1705<constant>V4L2_CID_EXPOSURE_AUTO</constant> is set to
1706<constant>AUTO</constant> or <constant>APERTURE_PRIORITY</constant>,
1707this control determines if the device may dynamically vary the frame
1708rate. By default this feature is disabled (0) and the frame rate must
1709remain constant.</entry>
1710 </row>
1711 <row><entry></entry></row>
1712
1713 <row>
1714 <entry spanname="id"><constant>V4L2_CID_PAN_RELATIVE</constant>&nbsp;</entry>
1715 <entry>integer</entry>
1716 </row><row><entry spanname="descr">This control turns the
1717camera horizontally by the specified amount. The unit is undefined. A
1718positive value moves the camera to the right (clockwise when viewed
1719from above), a negative value to the left. A value of zero does not
1720cause motion. This is a write-only control.</entry>
1721 </row>
1722 <row><entry></entry></row>
1723
1724 <row>
1725 <entry spanname="id"><constant>V4L2_CID_TILT_RELATIVE</constant>&nbsp;</entry>
1726 <entry>integer</entry>
1727 </row><row><entry spanname="descr">This control turns the
1728camera vertically by the specified amount. The unit is undefined. A
1729positive value moves the camera up, a negative value down. A value of
1730zero does not cause motion. This is a write-only control.</entry>
1731 </row>
1732 <row><entry></entry></row>
1733
1734 <row>
1735 <entry spanname="id"><constant>V4L2_CID_PAN_RESET</constant>&nbsp;</entry>
1736 <entry>button</entry>
1737 </row><row><entry spanname="descr">When this control is set,
1738the camera moves horizontally to the default position.</entry>
1739 </row>
1740 <row><entry></entry></row>
1741
1742 <row>
1743 <entry spanname="id"><constant>V4L2_CID_TILT_RESET</constant>&nbsp;</entry>
1744 <entry>button</entry>
1745 </row><row><entry spanname="descr">When this control is set,
1746the camera moves vertically to the default position.</entry>
1747 </row>
1748 <row><entry></entry></row>
1749
1750 <row>
1751 <entry spanname="id"><constant>V4L2_CID_PAN_ABSOLUTE</constant>&nbsp;</entry>
1752 <entry>integer</entry>
1753 </row><row><entry spanname="descr">This control
1754turns the camera horizontally to the specified position. Positive
1755values move the camera to the right (clockwise when viewed from above),
1756negative values to the left. Drivers should interpret the values as arc
1757seconds, with valid values between -180 * 3600 and +180 * 3600
1758inclusive.</entry>
1759 </row>
1760 <row><entry></entry></row>
1761
1762 <row>
1763 <entry spanname="id"><constant>V4L2_CID_TILT_ABSOLUTE</constant>&nbsp;</entry>
1764 <entry>integer</entry>
1765 </row><row><entry spanname="descr">This control
1766turns the camera vertically to the specified position. Positive values
1767move the camera up, negative values down. Drivers should interpret the
1768values as arc seconds, with valid values between -180 * 3600 and +180
1769* 3600 inclusive.</entry>
1770 </row>
1771 <row><entry></entry></row>
1772
1773 <row>
1774 <entry spanname="id"><constant>V4L2_CID_FOCUS_ABSOLUTE</constant>&nbsp;</entry>
1775 <entry>integer</entry>
1776 </row><row><entry spanname="descr">This control sets the
1777focal point of the camera to the specified position. The unit is
1778undefined. Positive values set the focus closer to the camera,
1779negative values towards infinity.</entry>
1780 </row>
1781 <row><entry></entry></row>
1782
1783 <row>
1784 <entry spanname="id"><constant>V4L2_CID_FOCUS_RELATIVE</constant>&nbsp;</entry>
1785 <entry>integer</entry>
1786 </row><row><entry spanname="descr">This control moves the
1787focal point of the camera by the specified amount. The unit is
1788undefined. Positive values move the focus closer to the camera,
1789negative values towards infinity. This is a write-only control.</entry>
1790 </row>
1791 <row><entry></entry></row>
1792
1793 <row>
1794 <entry spanname="id"><constant>V4L2_CID_FOCUS_AUTO</constant>&nbsp;</entry>
1795 <entry>boolean</entry>
1796 </row><row><entry spanname="descr">Enables automatic focus
1797adjustments. The effect of manual focus adjustments while this feature
1798is enabled is undefined, drivers should ignore such requests.</entry>
1799 </row>
1800 <row><entry></entry></row>
1801
1802 <row>
1803 <entry spanname="id"><constant>V4L2_CID_ZOOM_ABSOLUTE</constant>&nbsp;</entry>
1804 <entry>integer</entry>
1805 </row><row><entry spanname="descr">Specify the objective lens
1806focal length as an absolute value. The zoom unit is driver-specific and its
1807value should be a positive integer.</entry>
1808 </row>
1809 <row><entry></entry></row>
1810
1811 <row>
1812 <entry spanname="id"><constant>V4L2_CID_ZOOM_RELATIVE</constant>&nbsp;</entry>
1813 <entry>integer</entry>
1814 </row><row><entry spanname="descr">Specify the objective lens
1815focal length relatively to the current value. Positive values move the zoom
1816lens group towards the telephoto direction, negative values towards the
1817wide-angle direction. The zoom unit is driver-specific. This is a write-only control.</entry>
1818 </row>
1819 <row><entry></entry></row>
1820
1821 <row>
1822 <entry spanname="id"><constant>V4L2_CID_ZOOM_CONTINUOUS</constant>&nbsp;</entry>
1823 <entry>integer</entry>
1824 </row><row><entry spanname="descr">Move the objective lens group
1825at the specified speed until it reaches physical device limits or until an
1826explicit request to stop the movement. A positive value moves the zoom lens
1827group towards the telephoto direction. A value of zero stops the zoom lens
1828group movement. A negative value moves the zoom lens group towards the
1829wide-angle direction. The zoom speed unit is driver-specific.</entry>
1830 </row>
1831 <row><entry></entry></row>
1832
48213fe3
LP		 1833 <row>
1834 <entry spanname="id"><constant>V4L2_CID_IRIS_ABSOLUTE</constant>&nbsp;</entry>
1835 <entry>integer</entry>
1836 </row><row><entry spanname="descr">This control sets the
1837camera's aperture to the specified value. The unit is undefined.
1838Larger values open the iris wider, smaller values close it.</entry>
1839 </row>
1840 <row><entry></entry></row>
1841
1842 <row>
1843 <entry spanname="id"><constant>V4L2_CID_IRIS_RELATIVE</constant>&nbsp;</entry>
1844 <entry>integer</entry>
1845 </row><row><entry spanname="descr">This control modifies the
1846camera's aperture by the specified amount. The unit is undefined.
1847Positive values open the iris one step further, negative values close
1848it one step further. This is a write-only control.</entry>
1849 </row>
1850 <row><entry></entry></row>
1851
8e080c2e
MCC		 1852 <row>
1853 <entry spanname="id"><constant>V4L2_CID_PRIVACY</constant>&nbsp;</entry>
1854 <entry>boolean</entry>
1855 </row><row><entry spanname="descr">Prevent video from being acquired
1856by the camera. When this control is set to <constant>TRUE</constant> (1), no
1857image can be captured by the camera. Common means to enforce privacy are
1858mechanical obturation of the sensor and firmware image processing, but the
1859device is not restricted to these methods. Devices that implement the privacy
1860control must support read access and may support write access.</entry>
1861 </row>
1862
1863 <row>
1864 <entry spanname="id"><constant>V4L2_CID_BAND_STOP_FILTER</constant>&nbsp;</entry>
1865 <entry>integer</entry>
1866 </row><row><entry spanname="descr">Switch the band-stop filter of a
1867camera sensor on or off, or specify its strength. Such band-stop filters can
1868be used, for example, to filter out the fluorescent light component.</entry>
1869 </row>
1870 <row><entry></entry></row>
1871 </tbody>
1872 </tgroup>
1873 </table>
1874 </section>
1875
1876 <section id="fm-tx-controls">
1877 <title>FM Transmitter Control Reference</title>
1878
1879 <para>The FM Transmitter (FM_TX) class includes controls for common features of
1880FM transmissions capable devices. Currently this class includes parameters for audio
1881compression, pilot tone generation, audio deviation limiter, RDS transmission and
1882tuning power features.</para>
1883
1884 <table pgwide="1" frame="none" id="fm-tx-control-id">
1885 <title>FM_TX Control IDs</title>
1886
1887 <tgroup cols="4">
1888 <colspec colname="c1" colwidth="1*" />
1889 <colspec colname="c2" colwidth="6*" />
1890 <colspec colname="c3" colwidth="2*" />
1891 <colspec colname="c4" colwidth="6*" />
1892 <spanspec namest="c1" nameend="c2" spanname="id" />
1893 <spanspec namest="c2" nameend="c4" spanname="descr" />
1894 <thead>
1895 <row>
1896 <entry spanname="id" align="left">ID</entry>
1897 <entry align="left">Type</entry>
1898 </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
1899 </row>
1900 </thead>
1901 <tbody valign="top">
1902 <row><entry></entry></row>
1903 <row>
1904 <entry spanname="id"><constant>V4L2_CID_FM_TX_CLASS</constant>&nbsp;</entry>
1905 <entry>class</entry>
1906 </row><row><entry spanname="descr">The FM_TX class
1907descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a
1908description of this control class.</entry>
1909 </row>
1910 <row>
1911 <entry spanname="id"><constant>V4L2_CID_RDS_TX_DEVIATION</constant>&nbsp;</entry>
1912 <entry>integer</entry>
1913 </row>
1914 <row><entry spanname="descr">Configures RDS signal frequency deviation level in Hz.
1915The range and step are driver-specific.</entry>
1916 </row>
1917 <row>
1918 <entry spanname="id"><constant>V4L2_CID_RDS_TX_PI</constant>&nbsp;</entry>
1919 <entry>integer</entry>
1920 </row>
1921 <row><entry spanname="descr">Sets the RDS Programme Identification field
1922for transmission.</entry>
1923 </row>
1924 <row>
1925 <entry spanname="id"><constant>V4L2_CID_RDS_TX_PTY</constant>&nbsp;</entry>
1926 <entry>integer</entry>
1927 </row>
1928 <row><entry spanname="descr">Sets the RDS Programme Type field for transmission.
1929This encodes up to 31 pre-defined programme types.</entry>
1930 </row>
1931 <row>
1932 <entry spanname="id"><constant>V4L2_CID_RDS_TX_PS_NAME</constant>&nbsp;</entry>
1933 <entry>string</entry>
1934 </row>
1935 <row><entry spanname="descr">Sets the Programme Service name (PS_NAME) for transmission.
1936It is intended for static display on a receiver. It is the primary aid to listeners in programme service
1937identification and selection. In Annex E of <xref linkend="en50067" />, the RDS specification,
1938there is a full description of the correct character encoding for Programme Service name strings.
1939Also from RDS specification, PS is usually a single eight character text. However, it is also possible
1940to find receivers which can scroll strings sized as 8 x N characters. So, this control must be configured
1941with steps of 8 characters. The result is it must always contain a string with size multiple of 8.</entry>
1942 </row>
1943 <row>
1944 <entry spanname="id"><constant>V4L2_CID_RDS_TX_RADIO_TEXT</constant>&nbsp;</entry>
1945 <entry>string</entry>
1946 </row>
1947 <row><entry spanname="descr">Sets the Radio Text info for transmission. It is a textual description of
1948what is being broadcasted. RDS Radio Text can be applied when broadcaster wishes to transmit longer PS names,
1949programme-related information or any other text. In these cases, RadioText should be used in addition to
1950<constant>V4L2_CID_RDS_TX_PS_NAME</constant>. The encoding for Radio Text strings is also fully described
1951in Annex E of <xref linkend="en50067" />. The length of Radio Text strings depends on which RDS Block is being
1952used to transmit it, either 32 (2A block) or 64 (2B block). However, it is also possible
1953to find receivers which can scroll strings sized as 32 x N or 64 x N characters. So, this control must be configured
1954with steps of 32 or 64 characters. The result is it must always contain a string with size multiple of 32 or 64. </entry>
1955 </row>
1956 <row>
1957 <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_ENABLED</constant>&nbsp;</entry>
1958 <entry>boolean</entry>
1959 </row>
1960 <row><entry spanname="descr">Enables or disables the audio deviation limiter feature.
1961The limiter is useful when trying to maximize the audio volume, minimize receiver-generated
1962distortion and prevent overmodulation.
1963</entry>
1964 </row>
1965 <row>
1966 <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_RELEASE_TIME</constant>&nbsp;</entry>
1967 <entry>integer</entry>
1968 </row>
1969 <row><entry spanname="descr">Sets the audio deviation limiter feature release time.
1970Unit is in useconds. Step and range are driver-specific.</entry>
1971 </row>
1972 <row>
1973 <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_DEVIATION</constant>&nbsp;</entry>
1974 <entry>integer</entry>
1975 </row>
1976 <row><entry spanname="descr">Configures audio frequency deviation level in Hz.
1977The range and step are driver-specific.</entry>
1978 </row>
1979 <row>
1980 <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ENABLED</constant>&nbsp;</entry>
1981 <entry>boolean</entry>
1982 </row>
1983 <row><entry spanname="descr">Enables or disables the audio compression feature.
1984This feature amplifies signals below the threshold by a fixed gain and compresses audio
1985signals above the threshold by the ratio of Threshold/(Gain + Threshold).</entry>
1986 </row>
1987 <row>
1988 <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_GAIN</constant>&nbsp;</entry>
1989 <entry>integer</entry>
1990 </row>
1991 <row><entry spanname="descr">Sets the gain for audio compression feature. It is
1992a dB value. The range and step are driver-specific.</entry>
1993 </row>
1994 <row>
1995 <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_THRESHOLD</constant>&nbsp;</entry>
1996 <entry>integer</entry>
1997 </row>
1998 <row><entry spanname="descr">Sets the threshold level for audio compression freature.
1999It is a dB value. The range and step are driver-specific.</entry>
2000 </row>
2001 <row>
2002 <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME</constant>&nbsp;</entry>
2003 <entry>integer</entry>
2004 </row>
2005 <row><entry spanname="descr">Sets the attack time for audio compression feature.
2006It is a useconds value. The range and step are driver-specific.</entry>
2007 </row>
2008 <row>
2009 <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME</constant>&nbsp;</entry>
2010 <entry>integer</entry>
2011 </row>
2012 <row><entry spanname="descr">Sets the release time for audio compression feature.
2013It is a useconds value. The range and step are driver-specific.</entry>
2014 </row>
2015 <row>
2016 <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_ENABLED</constant>&nbsp;</entry>
2017 <entry>boolean</entry>
2018 </row>
2019 <row><entry spanname="descr">Enables or disables the pilot tone generation feature.</entry>
2020 </row>
2021 <row>
2022 <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_DEVIATION</constant>&nbsp;</entry>
2023 <entry>integer</entry>
2024 </row>
2025 <row><entry spanname="descr">Configures pilot tone frequency deviation level. Unit is
2026in Hz. The range and step are driver-specific.</entry>
2027 </row>
2028 <row>
2029 <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_FREQUENCY</constant>&nbsp;</entry>
2030 <entry>integer</entry>
2031 </row>
2032 <row><entry spanname="descr">Configures pilot tone frequency value. Unit is
2033in Hz. The range and step are driver-specific.</entry>
2034 </row>
2035 <row>
2036 <entry spanname="id"><constant>V4L2_CID_TUNE_PREEMPHASIS</constant>&nbsp;</entry>
2037 <entry>integer</entry>
2038 </row>
2039 <row id="v4l2-preemphasis"><entry spanname="descr">Configures the pre-emphasis value for broadcasting.
2040A pre-emphasis filter is applied to the broadcast to accentuate the high audio frequencies.
2041Depending on the region, a time constant of either 50 or 75 useconds is used. The enum&nbsp;v4l2_preemphasis
2042defines possible values for pre-emphasis. Here they are:</entry>
2043 </row><row>
2044 <entrytbl spanname="descr" cols="2">
2045 <tbody valign="top">
2046 <row>
2047 <entry><constant>V4L2_PREEMPHASIS_DISABLED</constant>&nbsp;</entry>
2048 <entry>No pre-emphasis is applied.</entry>
2049 </row>
2050 <row>
2051 <entry><constant>V4L2_PREEMPHASIS_50_uS</constant>&nbsp;</entry>
2052 <entry>A pre-emphasis of 50 uS is used.</entry>
2053 </row>
2054 <row>
2055 <entry><constant>V4L2_PREEMPHASIS_75_uS</constant>&nbsp;</entry>
2056 <entry>A pre-emphasis of 75 uS is used.</entry>
2057 </row>
2058 </tbody>
2059 </entrytbl>
2060
2061 </row>
2062 <row>
2063 <entry spanname="id"><constant>V4L2_CID_TUNE_POWER_LEVEL</constant>&nbsp;</entry>
2064 <entry>integer</entry>
2065 </row>
2066 <row><entry spanname="descr">Sets the output power level for signal transmission.
2067Unit is in dBuV. Range and step are driver-specific.</entry>
2068 </row>
2069 <row>
2070 <entry spanname="id"><constant>V4L2_CID_TUNE_ANTENNA_CAPACITOR</constant>&nbsp;</entry>
2071 <entry>integer</entry>
2072 </row>
2073 <row><entry spanname="descr">This selects the value of antenna tuning capacitor
2074manually or automatically if set to zero. Unit, range and step are driver-specific.</entry>
2075 </row>
2076 <row><entry></entry></row>
2077 </tbody>
2078 </tgroup>
2079 </table>
2080
2081<para>For more details about RDS specification, refer to
2082<xref linkend="en50067" /> document, from CENELEC.</para>
2083 </section>
2084</section>
2085
2086 <!--
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