1 .. -*- coding: utf-8; mode: rst -*-
13 The control mechanism as originally designed was meant to be used for
14 user settings (brightness, saturation, etc). However, it turned out to
15 be a very useful model for implementing more complicated driver APIs
16 where each driver implements only a subset of a larger API.
18 The MPEG encoding API was the driving force behind designing and
19 implementing this extended control mechanism: the MPEG standard is quite
20 large and the currently supported hardware MPEG encoders each only
21 implement a subset of this standard. Further more, many parameters
22 relating to how the video is encoded into an MPEG stream are specific to
23 the MPEG encoding chip since the MPEG standard only defines the format
24 of the resulting MPEG stream, not how the video is actually encoded into
27 Unfortunately, the original control API lacked some features needed for
28 these new uses and so it was extended into the (not terribly originally
29 named) extended control API.
31 Even though the MPEG encoding API was the first effort to use the
32 Extended Control API, nowadays there are also other classes of Extended
33 Controls, such as Camera Controls and FM Transmitter Controls. The
34 Extended Controls API as well as all Extended Controls classes are
35 described in the following text.
38 The Extended Control API
39 ========================
41 Three new ioctls are available:
42 :ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>`,
43 :ref:`VIDIOC_S_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` and
44 :ref:`VIDIOC_TRY_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>`. These ioctls act
45 on arrays of controls (as opposed to the
46 :ref:`VIDIOC_G_CTRL <VIDIOC_G_CTRL>` and
47 :ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` ioctls that act on a single
48 control). This is needed since it is often required to atomically change
49 several controls at once.
51 Each of the new ioctls expects a pointer to a struct
52 :c:type:`v4l2_ext_controls`. This structure
53 contains a pointer to the control array, a count of the number of
54 controls in that array and a control class. Control classes are used to
55 group similar controls into a single class. For example, control class
56 ``V4L2_CTRL_CLASS_USER`` contains all user controls (i. e. all controls
57 that can also be set using the old :ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>`
58 ioctl). Control class ``V4L2_CTRL_CLASS_MPEG`` contains all controls
59 relating to MPEG encoding, etc.
61 All controls in the control array must belong to the specified control
62 class. An error is returned if this is not the case.
64 It is also possible to use an empty control array (``count`` == 0) to check
65 whether the specified control class is supported.
67 The control array is a struct
68 :c:type:`v4l2_ext_control` array. The
69 struct :c:type:`v4l2_ext_control` is very similar to
70 struct :c:type:`v4l2_control`, except for the fact that
71 it also allows for 64-bit values and pointers to be passed.
73 Since the struct :c:type:`v4l2_ext_control` supports
74 pointers it is now also possible to have controls with compound types
75 such as N-dimensional arrays and/or structures. You need to specify the
76 ``V4L2_CTRL_FLAG_NEXT_COMPOUND`` when enumerating controls to actually
77 be able to see such compound controls. In other words, these controls
78 with compound types should only be used programmatically.
80 Since such compound controls need to expose more information about
81 themselves than is possible with
82 :ref:`VIDIOC_QUERYCTRL` the
83 :ref:`VIDIOC_QUERY_EXT_CTRL <VIDIOC_QUERYCTRL>` ioctl was added. In
84 particular, this ioctl gives the dimensions of the N-dimensional array
85 if this control consists of more than one element.
89 #. It is important to realize that due to the flexibility of controls it is
90 necessary to check whether the control you want to set actually is
91 supported in the driver and what the valid range of values is. So use
92 the :ref:`VIDIOC_QUERYCTRL` (or :ref:`VIDIOC_QUERY_EXT_CTRL
93 <VIDIOC_QUERYCTRL>`) and :ref:`VIDIOC_QUERYMENU <VIDIOC_QUERYCTRL>`
96 #. It is possible that some of the menu indices in a control of
97 type ``V4L2_CTRL_TYPE_MENU`` may not be supported (``VIDIOC_QUERYMENU``
98 will return an error). A good example is the list of supported MPEG
99 audio bitrates. Some drivers only support one or two bitrates, others
100 support a wider range.
102 All controls use machine endianness.
105 Enumerating Extended Controls
106 =============================
108 The recommended way to enumerate over the extended controls is by using
109 :ref:`VIDIOC_QUERYCTRL` in combination with the
110 ``V4L2_CTRL_FLAG_NEXT_CTRL`` flag:
115 struct v4l2_queryctrl qctrl;
117 qctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL;
118 while (0 == ioctl (fd, VIDIOC_QUERYCTRL, &qctrl)) {
120 qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
123 The initial control ID is set to 0 ORed with the
124 ``V4L2_CTRL_FLAG_NEXT_CTRL`` flag. The ``VIDIOC_QUERYCTRL`` ioctl will
125 return the first control with a higher ID than the specified one. When
126 no such controls are found an error is returned.
128 If you want to get all controls within a specific control class, then
129 you can set the initial ``qctrl.id`` value to the control class and add
130 an extra check to break out of the loop when a control of another
131 control class is found:
136 qctrl.id = V4L2_CTRL_CLASS_MPEG | V4L2_CTRL_FLAG_NEXT_CTRL;
137 while (0 == ioctl(fd, VIDIOC_QUERYCTRL, &qctrl)) {
138 if (V4L2_CTRL_ID2CLASS(qctrl.id) != V4L2_CTRL_CLASS_MPEG)
141 qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
144 The 32-bit ``qctrl.id`` value is subdivided into three bit ranges: the
145 top 4 bits are reserved for flags (e. g. ``V4L2_CTRL_FLAG_NEXT_CTRL``)
146 and are not actually part of the ID. The remaining 28 bits form the
147 control ID, of which the most significant 12 bits define the control
148 class and the least significant 16 bits identify the control within the
149 control class. It is guaranteed that these last 16 bits are always
150 non-zero for controls. The range of 0x1000 and up are reserved for
151 driver-specific controls. The macro ``V4L2_CTRL_ID2CLASS(id)`` returns
152 the control class ID based on a control ID.
154 If the driver does not support extended controls, then
155 ``VIDIOC_QUERYCTRL`` will fail when used in combination with
156 ``V4L2_CTRL_FLAG_NEXT_CTRL``. In that case the old method of enumerating
157 control should be used (see :ref:`enum_all_controls`). But if it is
158 supported, then it is guaranteed to enumerate over all controls,
159 including driver-private controls.
162 Creating Control Panels
163 =======================
165 It is possible to create control panels for a graphical user interface
166 where the user can select the various controls. Basically you will have
167 to iterate over all controls using the method described above. Each
168 control class starts with a control of type
169 ``V4L2_CTRL_TYPE_CTRL_CLASS``. ``VIDIOC_QUERYCTRL`` will return the name
170 of this control class which can be used as the title of a tab page
171 within a control panel.
173 The flags field of struct :ref:`v4l2_queryctrl <v4l2-queryctrl>` also
174 contains hints on the behavior of the control. See the
175 :ref:`VIDIOC_QUERYCTRL` documentation for more
181 Codec Control Reference
182 =======================
184 Below all controls within the Codec control class are described. First
185 the generic controls, then controls specific for certain hardware.
189 These controls are applicable to all codecs and not just MPEG. The
190 defines are prefixed with V4L2_CID_MPEG/V4L2_MPEG as the controls
191 were originally made for MPEG codecs and later extended to cover all
195 Generic Codec Controls
196 ----------------------
204 ``V4L2_CID_MPEG_CLASS (class)``
205 The Codec class descriptor. Calling
206 :ref:`VIDIOC_QUERYCTRL` for this control will
207 return a description of this control class. This description can be
208 used as the caption of a Tab page in a GUI, for example.
210 .. _v4l2-mpeg-stream-type:
212 ``V4L2_CID_MPEG_STREAM_TYPE``
215 enum v4l2_mpeg_stream_type -
216 The MPEG-1, -2 or -4 output stream type. One cannot assume anything
217 here. Each hardware MPEG encoder tends to support different subsets
218 of the available MPEG stream types. This control is specific to
219 multiplexed MPEG streams. The currently defined stream types are:
227 * - ``V4L2_MPEG_STREAM_TYPE_MPEG2_PS``
228 - MPEG-2 program stream
229 * - ``V4L2_MPEG_STREAM_TYPE_MPEG2_TS``
230 - MPEG-2 transport stream
231 * - ``V4L2_MPEG_STREAM_TYPE_MPEG1_SS``
232 - MPEG-1 system stream
233 * - ``V4L2_MPEG_STREAM_TYPE_MPEG2_DVD``
234 - MPEG-2 DVD-compatible stream
235 * - ``V4L2_MPEG_STREAM_TYPE_MPEG1_VCD``
236 - MPEG-1 VCD-compatible stream
237 * - ``V4L2_MPEG_STREAM_TYPE_MPEG2_SVCD``
238 - MPEG-2 SVCD-compatible stream
242 ``V4L2_CID_MPEG_STREAM_PID_PMT (integer)``
243 Program Map Table Packet ID for the MPEG transport stream (default
246 ``V4L2_CID_MPEG_STREAM_PID_AUDIO (integer)``
247 Audio Packet ID for the MPEG transport stream (default 256)
249 ``V4L2_CID_MPEG_STREAM_PID_VIDEO (integer)``
250 Video Packet ID for the MPEG transport stream (default 260)
252 ``V4L2_CID_MPEG_STREAM_PID_PCR (integer)``
253 Packet ID for the MPEG transport stream carrying PCR fields (default
256 ``V4L2_CID_MPEG_STREAM_PES_ID_AUDIO (integer)``
257 Audio ID for MPEG PES
259 ``V4L2_CID_MPEG_STREAM_PES_ID_VIDEO (integer)``
260 Video ID for MPEG PES
262 .. _v4l2-mpeg-stream-vbi-fmt:
264 ``V4L2_CID_MPEG_STREAM_VBI_FMT``
267 enum v4l2_mpeg_stream_vbi_fmt -
268 Some cards can embed VBI data (e. g. Closed Caption, Teletext) into
269 the MPEG stream. This control selects whether VBI data should be
270 embedded, and if so, what embedding method should be used. The list
271 of possible VBI formats depends on the driver. The currently defined
272 VBI format types are:
276 .. tabularcolumns:: |p{6 cm}|p{11.5cm}|
282 * - ``V4L2_MPEG_STREAM_VBI_FMT_NONE``
283 - No VBI in the MPEG stream
284 * - ``V4L2_MPEG_STREAM_VBI_FMT_IVTV``
285 - VBI in private packets, IVTV format (documented in the kernel
287 ``Documentation/media/v4l-drivers/cx2341x.rst``)
291 .. _v4l2-mpeg-audio-sampling-freq:
293 ``V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ``
296 enum v4l2_mpeg_audio_sampling_freq -
297 MPEG Audio sampling frequency. Possible values are:
305 * - ``V4L2_MPEG_AUDIO_SAMPLING_FREQ_44100``
307 * - ``V4L2_MPEG_AUDIO_SAMPLING_FREQ_48000``
309 * - ``V4L2_MPEG_AUDIO_SAMPLING_FREQ_32000``
314 .. _v4l2-mpeg-audio-encoding:
316 ``V4L2_CID_MPEG_AUDIO_ENCODING``
319 enum v4l2_mpeg_audio_encoding -
320 MPEG Audio encoding. This control is specific to multiplexed MPEG
321 streams. Possible values are:
329 * - ``V4L2_MPEG_AUDIO_ENCODING_LAYER_1``
330 - MPEG-1/2 Layer I encoding
331 * - ``V4L2_MPEG_AUDIO_ENCODING_LAYER_2``
332 - MPEG-1/2 Layer II encoding
333 * - ``V4L2_MPEG_AUDIO_ENCODING_LAYER_3``
334 - MPEG-1/2 Layer III encoding
335 * - ``V4L2_MPEG_AUDIO_ENCODING_AAC``
336 - MPEG-2/4 AAC (Advanced Audio Coding)
337 * - ``V4L2_MPEG_AUDIO_ENCODING_AC3``
338 - AC-3 aka ATSC A/52 encoding
342 .. _v4l2-mpeg-audio-l1-bitrate:
344 ``V4L2_CID_MPEG_AUDIO_L1_BITRATE``
347 enum v4l2_mpeg_audio_l1_bitrate -
348 MPEG-1/2 Layer I bitrate. Possible values are:
356 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_32K``
358 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_64K``
360 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_96K``
362 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_128K``
364 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_160K``
366 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_192K``
368 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_224K``
370 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_256K``
372 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_288K``
374 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_320K``
376 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_352K``
378 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_384K``
380 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_416K``
382 * - ``V4L2_MPEG_AUDIO_L1_BITRATE_448K``
387 .. _v4l2-mpeg-audio-l2-bitrate:
389 ``V4L2_CID_MPEG_AUDIO_L2_BITRATE``
392 enum v4l2_mpeg_audio_l2_bitrate -
393 MPEG-1/2 Layer II bitrate. Possible values are:
401 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_32K``
403 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_48K``
405 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_56K``
407 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_64K``
409 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_80K``
411 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_96K``
413 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_112K``
415 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_128K``
417 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_160K``
419 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_192K``
421 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_224K``
423 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_256K``
425 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_320K``
427 * - ``V4L2_MPEG_AUDIO_L2_BITRATE_384K``
432 .. _v4l2-mpeg-audio-l3-bitrate:
434 ``V4L2_CID_MPEG_AUDIO_L3_BITRATE``
437 enum v4l2_mpeg_audio_l3_bitrate -
438 MPEG-1/2 Layer III bitrate. Possible values are:
446 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_32K``
448 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_40K``
450 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_48K``
452 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_56K``
454 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_64K``
456 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_80K``
458 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_96K``
460 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_112K``
462 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_128K``
464 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_160K``
466 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_192K``
468 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_224K``
470 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_256K``
472 * - ``V4L2_MPEG_AUDIO_L3_BITRATE_320K``
477 ``V4L2_CID_MPEG_AUDIO_AAC_BITRATE (integer)``
478 AAC bitrate in bits per second.
480 .. _v4l2-mpeg-audio-ac3-bitrate:
482 ``V4L2_CID_MPEG_AUDIO_AC3_BITRATE``
485 enum v4l2_mpeg_audio_ac3_bitrate -
486 AC-3 bitrate. Possible values are:
494 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_32K``
496 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_40K``
498 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_48K``
500 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_56K``
502 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_64K``
504 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_80K``
506 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_96K``
508 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_112K``
510 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_128K``
512 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_160K``
514 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_192K``
516 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_224K``
518 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_256K``
520 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_320K``
522 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_384K``
524 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_448K``
526 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_512K``
528 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_576K``
530 * - ``V4L2_MPEG_AUDIO_AC3_BITRATE_640K``
535 .. _v4l2-mpeg-audio-mode:
537 ``V4L2_CID_MPEG_AUDIO_MODE``
540 enum v4l2_mpeg_audio_mode -
541 MPEG Audio mode. Possible values are:
549 * - ``V4L2_MPEG_AUDIO_MODE_STEREO``
551 * - ``V4L2_MPEG_AUDIO_MODE_JOINT_STEREO``
553 * - ``V4L2_MPEG_AUDIO_MODE_DUAL``
555 * - ``V4L2_MPEG_AUDIO_MODE_MONO``
560 .. _v4l2-mpeg-audio-mode-extension:
562 ``V4L2_CID_MPEG_AUDIO_MODE_EXTENSION``
565 enum v4l2_mpeg_audio_mode_extension -
566 Joint Stereo audio mode extension. In Layer I and II they indicate
567 which subbands are in intensity stereo. All other subbands are coded
568 in stereo. Layer III is not (yet) supported. Possible values are:
576 * - ``V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_4``
577 - Subbands 4-31 in intensity stereo
578 * - ``V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_8``
579 - Subbands 8-31 in intensity stereo
580 * - ``V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_12``
581 - Subbands 12-31 in intensity stereo
582 * - ``V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_16``
583 - Subbands 16-31 in intensity stereo
587 .. _v4l2-mpeg-audio-emphasis:
589 ``V4L2_CID_MPEG_AUDIO_EMPHASIS``
592 enum v4l2_mpeg_audio_emphasis -
593 Audio Emphasis. Possible values are:
601 * - ``V4L2_MPEG_AUDIO_EMPHASIS_NONE``
603 * - ``V4L2_MPEG_AUDIO_EMPHASIS_50_DIV_15_uS``
604 - 50/15 microsecond emphasis
605 * - ``V4L2_MPEG_AUDIO_EMPHASIS_CCITT_J17``
610 .. _v4l2-mpeg-audio-crc:
612 ``V4L2_CID_MPEG_AUDIO_CRC``
615 enum v4l2_mpeg_audio_crc -
616 CRC method. Possible values are:
624 * - ``V4L2_MPEG_AUDIO_CRC_NONE``
626 * - ``V4L2_MPEG_AUDIO_CRC_CRC16``
627 - 16 bit parity check
631 ``V4L2_CID_MPEG_AUDIO_MUTE (boolean)``
632 Mutes the audio when capturing. This is not done by muting audio
633 hardware, which can still produce a slight hiss, but in the encoder
634 itself, guaranteeing a fixed and reproducible audio bitstream. 0 =
637 .. _v4l2-mpeg-audio-dec-playback:
639 ``V4L2_CID_MPEG_AUDIO_DEC_PLAYBACK``
642 enum v4l2_mpeg_audio_dec_playback -
643 Determines how monolingual audio should be played back. Possible
648 .. tabularcolumns:: |p{9.0cm}|p{8.5cm}|
654 * - ``V4L2_MPEG_AUDIO_DEC_PLAYBACK_AUTO``
655 - Automatically determines the best playback mode.
656 * - ``V4L2_MPEG_AUDIO_DEC_PLAYBACK_STEREO``
658 * - ``V4L2_MPEG_AUDIO_DEC_PLAYBACK_LEFT``
659 - Left channel playback.
660 * - ``V4L2_MPEG_AUDIO_DEC_PLAYBACK_RIGHT``
661 - Right channel playback.
662 * - ``V4L2_MPEG_AUDIO_DEC_PLAYBACK_MONO``
664 * - ``V4L2_MPEG_AUDIO_DEC_PLAYBACK_SWAPPED_STEREO``
665 - Stereo playback with swapped left and right channels.
669 .. _v4l2-mpeg-audio-dec-multilingual-playback:
671 ``V4L2_CID_MPEG_AUDIO_DEC_MULTILINGUAL_PLAYBACK``
674 enum v4l2_mpeg_audio_dec_playback -
675 Determines how multilingual audio should be played back.
677 .. _v4l2-mpeg-video-encoding:
679 ``V4L2_CID_MPEG_VIDEO_ENCODING``
682 enum v4l2_mpeg_video_encoding -
683 MPEG Video encoding method. This control is specific to multiplexed
684 MPEG streams. Possible values are:
692 * - ``V4L2_MPEG_VIDEO_ENCODING_MPEG_1``
693 - MPEG-1 Video encoding
694 * - ``V4L2_MPEG_VIDEO_ENCODING_MPEG_2``
695 - MPEG-2 Video encoding
696 * - ``V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC``
697 - MPEG-4 AVC (H.264) Video encoding
701 .. _v4l2-mpeg-video-aspect:
703 ``V4L2_CID_MPEG_VIDEO_ASPECT``
706 enum v4l2_mpeg_video_aspect -
707 Video aspect. Possible values are:
715 * - ``V4L2_MPEG_VIDEO_ASPECT_1x1``
716 * - ``V4L2_MPEG_VIDEO_ASPECT_4x3``
717 * - ``V4L2_MPEG_VIDEO_ASPECT_16x9``
718 * - ``V4L2_MPEG_VIDEO_ASPECT_221x100``
722 ``V4L2_CID_MPEG_VIDEO_B_FRAMES (integer)``
723 Number of B-Frames (default 2)
725 ``V4L2_CID_MPEG_VIDEO_GOP_SIZE (integer)``
726 GOP size (default 12)
728 ``V4L2_CID_MPEG_VIDEO_GOP_CLOSURE (boolean)``
729 GOP closure (default 1)
731 ``V4L2_CID_MPEG_VIDEO_PULLDOWN (boolean)``
732 Enable 3:2 pulldown (default 0)
734 .. _v4l2-mpeg-video-bitrate-mode:
736 ``V4L2_CID_MPEG_VIDEO_BITRATE_MODE``
739 enum v4l2_mpeg_video_bitrate_mode -
740 Video bitrate mode. Possible values are:
748 * - ``V4L2_MPEG_VIDEO_BITRATE_MODE_VBR``
750 * - ``V4L2_MPEG_VIDEO_BITRATE_MODE_CBR``
755 ``V4L2_CID_MPEG_VIDEO_BITRATE (integer)``
756 Video bitrate in bits per second.
758 ``V4L2_CID_MPEG_VIDEO_BITRATE_PEAK (integer)``
759 Peak video bitrate in bits per second. Must be larger or equal to
760 the average video bitrate. It is ignored if the video bitrate mode
761 is set to constant bitrate.
763 ``V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION (integer)``
764 For every captured frame, skip this many subsequent frames (default
767 ``V4L2_CID_MPEG_VIDEO_MUTE (boolean)``
768 "Mutes" the video to a fixed color when capturing. This is useful
769 for testing, to produce a fixed video bitstream. 0 = unmuted, 1 =
772 ``V4L2_CID_MPEG_VIDEO_MUTE_YUV (integer)``
773 Sets the "mute" color of the video. The supplied 32-bit integer is
774 interpreted as follows (bit 0 = least significant bit):
783 - V chrominance information
785 - U chrominance information
787 - Y luminance information
793 .. _v4l2-mpeg-video-dec-pts:
795 ``V4L2_CID_MPEG_VIDEO_DEC_PTS (integer64)``
796 This read-only control returns the 33-bit video Presentation Time
797 Stamp as defined in ITU T-REC-H.222.0 and ISO/IEC 13818-1 of the
798 currently displayed frame. This is the same PTS as is used in
799 :ref:`VIDIOC_DECODER_CMD`.
801 .. _v4l2-mpeg-video-dec-frame:
803 ``V4L2_CID_MPEG_VIDEO_DEC_FRAME (integer64)``
804 This read-only control returns the frame counter of the frame that
805 is currently displayed (decoded). This value is reset to 0 whenever
806 the decoder is started.
808 ``V4L2_CID_MPEG_VIDEO_DECODER_SLICE_INTERFACE (boolean)``
809 If enabled the decoder expects to receive a single slice per buffer,
810 otherwise the decoder expects a single frame in per buffer.
811 Applicable to the decoder, all codecs.
813 ``V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_ENABLE (boolean)``
814 Enable writing sample aspect ratio in the Video Usability
815 Information. Applicable to the H264 encoder.
817 .. _v4l2-mpeg-video-h264-vui-sar-idc:
819 ``V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC``
822 enum v4l2_mpeg_video_h264_vui_sar_idc -
823 VUI sample aspect ratio indicator for H.264 encoding. The value is
824 defined in the table E-1 in the standard. Applicable to the H264
833 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_UNSPECIFIED``
835 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_1x1``
837 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_12x11``
839 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_10x11``
841 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_16x11``
843 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_40x33``
845 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_24x11``
847 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_20x11``
849 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_32x11``
851 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_80x33``
853 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_18x11``
855 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_15x11``
857 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_64x33``
859 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_160x99``
861 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_4x3``
863 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_3x2``
865 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_2x1``
867 * - ``V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_EXTENDED``
872 ``V4L2_CID_MPEG_VIDEO_H264_VUI_EXT_SAR_WIDTH (integer)``
873 Extended sample aspect ratio width for H.264 VUI encoding.
874 Applicable to the H264 encoder.
876 ``V4L2_CID_MPEG_VIDEO_H264_VUI_EXT_SAR_HEIGHT (integer)``
877 Extended sample aspect ratio height for H.264 VUI encoding.
878 Applicable to the H264 encoder.
880 .. _v4l2-mpeg-video-h264-level:
882 ``V4L2_CID_MPEG_VIDEO_H264_LEVEL``
885 enum v4l2_mpeg_video_h264_level -
886 The level information for the H264 video elementary stream.
887 Applicable to the H264 encoder. Possible values are:
895 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_1_0``
897 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_1B``
899 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_1_1``
901 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_1_2``
903 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_1_3``
905 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_2_0``
907 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_2_1``
909 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_2_2``
911 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_3_0``
913 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_3_1``
915 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_3_2``
917 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_4_0``
919 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_4_1``
921 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_4_2``
923 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_5_0``
925 * - ``V4L2_MPEG_VIDEO_H264_LEVEL_5_1``
930 .. _v4l2-mpeg-video-mpeg4-level:
932 ``V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL``
935 enum v4l2_mpeg_video_mpeg4_level -
936 The level information for the MPEG4 elementary stream. Applicable to
937 the MPEG4 encoder. Possible values are:
945 * - ``V4L2_MPEG_VIDEO_MPEG4_LEVEL_0``
947 * - ``V4L2_MPEG_VIDEO_MPEG4_LEVEL_0B``
949 * - ``V4L2_MPEG_VIDEO_MPEG4_LEVEL_1``
951 * - ``V4L2_MPEG_VIDEO_MPEG4_LEVEL_2``
953 * - ``V4L2_MPEG_VIDEO_MPEG4_LEVEL_3``
955 * - ``V4L2_MPEG_VIDEO_MPEG4_LEVEL_3B``
957 * - ``V4L2_MPEG_VIDEO_MPEG4_LEVEL_4``
959 * - ``V4L2_MPEG_VIDEO_MPEG4_LEVEL_5``
964 .. _v4l2-mpeg-video-h264-profile:
966 ``V4L2_CID_MPEG_VIDEO_H264_PROFILE``
969 enum v4l2_mpeg_video_h264_profile -
970 The profile information for H264. Applicable to the H264 encoder.
979 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_BASELINE``
981 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_CONSTRAINED_BASELINE``
982 - Constrained Baseline profile
983 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_MAIN``
985 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_EXTENDED``
987 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_HIGH``
989 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_10``
991 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_422``
993 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_444_PREDICTIVE``
994 - High 444 Predictive profile
995 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_10_INTRA``
996 - High 10 Intra profile
997 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_422_INTRA``
998 - High 422 Intra profile
999 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_444_INTRA``
1000 - High 444 Intra profile
1001 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_CAVLC_444_INTRA``
1002 - CAVLC 444 Intra profile
1003 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_BASELINE``
1004 - Scalable Baseline profile
1005 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_HIGH``
1006 - Scalable High profile
1007 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_HIGH_INTRA``
1008 - Scalable High Intra profile
1009 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_STEREO_HIGH``
1010 - Stereo High profile
1011 * - ``V4L2_MPEG_VIDEO_H264_PROFILE_MULTIVIEW_HIGH``
1012 - Multiview High profile
1016 .. _v4l2-mpeg-video-mpeg4-profile:
1018 ``V4L2_CID_MPEG_VIDEO_MPEG4_PROFILE``
1021 enum v4l2_mpeg_video_mpeg4_profile -
1022 The profile information for MPEG4. Applicable to the MPEG4 encoder.
1023 Possible values are:
1031 * - ``V4L2_MPEG_VIDEO_MPEG4_PROFILE_SIMPLE``
1033 * - ``V4L2_MPEG_VIDEO_MPEG4_PROFILE_ADVANCED_SIMPLE``
1034 - Advanced Simple profile
1035 * - ``V4L2_MPEG_VIDEO_MPEG4_PROFILE_CORE``
1037 * - ``V4L2_MPEG_VIDEO_MPEG4_PROFILE_SIMPLE_SCALABLE``
1038 - Simple Scalable profile
1039 * - ``V4L2_MPEG_VIDEO_MPEG4_PROFILE_ADVANCED_CODING_EFFICIENCY``
1044 ``V4L2_CID_MPEG_VIDEO_MAX_REF_PIC (integer)``
1045 The maximum number of reference pictures used for encoding.
1046 Applicable to the encoder.
1048 .. _v4l2-mpeg-video-multi-slice-mode:
1050 ``V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE``
1053 enum v4l2_mpeg_video_multi_slice_mode -
1054 Determines how the encoder should handle division of frame into
1055 slices. Applicable to the encoder. Possible values are:
1059 .. tabularcolumns:: |p{8.7cm}|p{8.8cm}|
1065 * - ``V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_SINGLE``
1066 - Single slice per frame.
1067 * - ``V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB``
1068 - Multiple slices with set maximum number of macroblocks per slice.
1069 * - ``V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_BYTES``
1070 - Multiple slice with set maximum size in bytes per slice.
1074 ``V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_MB (integer)``
1075 The maximum number of macroblocks in a slice. Used when
1076 ``V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE`` is set to
1077 ``V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB``. Applicable to the
1080 ``V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_BYTES (integer)``
1081 The maximum size of a slice in bytes. Used when
1082 ``V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE`` is set to
1083 ``V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_BYTES``. Applicable to the
1086 .. _v4l2-mpeg-video-h264-loop-filter-mode:
1088 ``V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_MODE``
1091 enum v4l2_mpeg_video_h264_loop_filter_mode -
1092 Loop filter mode for H264 encoder. Possible values are:
1096 .. tabularcolumns:: |p{14.0cm}|p{3.5cm}|
1102 * - ``V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_ENABLED``
1103 - Loop filter is enabled.
1104 * - ``V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_DISABLED``
1105 - Loop filter is disabled.
1106 * - ``V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_DISABLED_AT_SLICE_BOUNDARY``
1107 - Loop filter is disabled at the slice boundary.
1111 ``V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_ALPHA (integer)``
1112 Loop filter alpha coefficient, defined in the H264 standard.
1113 Applicable to the H264 encoder.
1115 ``V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_BETA (integer)``
1116 Loop filter beta coefficient, defined in the H264 standard.
1117 Applicable to the H264 encoder.
1119 .. _v4l2-mpeg-video-h264-entropy-mode:
1121 ``V4L2_CID_MPEG_VIDEO_H264_ENTROPY_MODE``
1124 enum v4l2_mpeg_video_h264_entropy_mode -
1125 Entropy coding mode for H264 - CABAC/CAVALC. Applicable to the H264
1126 encoder. Possible values are:
1134 * - ``V4L2_MPEG_VIDEO_H264_ENTROPY_MODE_CAVLC``
1135 - Use CAVLC entropy coding.
1136 * - ``V4L2_MPEG_VIDEO_H264_ENTROPY_MODE_CABAC``
1137 - Use CABAC entropy coding.
1141 ``V4L2_CID_MPEG_VIDEO_H264_8X8_TRANSFORM (boolean)``
1142 Enable 8X8 transform for H264. Applicable to the H264 encoder.
1144 ``V4L2_CID_MPEG_VIDEO_CYCLIC_INTRA_REFRESH_MB (integer)``
1145 Cyclic intra macroblock refresh. This is the number of continuous
1146 macroblocks refreshed every frame. Each frame a successive set of
1147 macroblocks is refreshed until the cycle completes and starts from
1148 the top of the frame. Applicable to H264, H263 and MPEG4 encoder.
1150 ``V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE (boolean)``
1151 Frame level rate control enable. If this control is disabled then
1152 the quantization parameter for each frame type is constant and set
1153 with appropriate controls (e.g.
1154 ``V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP``). If frame rate control is
1155 enabled then quantization parameter is adjusted to meet the chosen
1156 bitrate. Minimum and maximum value for the quantization parameter
1157 can be set with appropriate controls (e.g.
1158 ``V4L2_CID_MPEG_VIDEO_H263_MIN_QP``). Applicable to encoders.
1160 ``V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE (boolean)``
1161 Macroblock level rate control enable. Applicable to the MPEG4 and
1164 ``V4L2_CID_MPEG_VIDEO_MPEG4_QPEL (boolean)``
1165 Quarter pixel motion estimation for MPEG4. Applicable to the MPEG4
1168 ``V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP (integer)``
1169 Quantization parameter for an I frame for H263. Valid range: from 1
1172 ``V4L2_CID_MPEG_VIDEO_H263_MIN_QP (integer)``
1173 Minimum quantization parameter for H263. Valid range: from 1 to 31.
1175 ``V4L2_CID_MPEG_VIDEO_H263_MAX_QP (integer)``
1176 Maximum quantization parameter for H263. Valid range: from 1 to 31.
1178 ``V4L2_CID_MPEG_VIDEO_H263_P_FRAME_QP (integer)``
1179 Quantization parameter for an P frame for H263. Valid range: from 1
1182 ``V4L2_CID_MPEG_VIDEO_H263_B_FRAME_QP (integer)``
1183 Quantization parameter for an B frame for H263. Valid range: from 1
1186 ``V4L2_CID_MPEG_VIDEO_H264_I_FRAME_QP (integer)``
1187 Quantization parameter for an I frame for H264. Valid range: from 0
1190 ``V4L2_CID_MPEG_VIDEO_H264_MIN_QP (integer)``
1191 Minimum quantization parameter for H264. Valid range: from 0 to 51.
1193 ``V4L2_CID_MPEG_VIDEO_H264_MAX_QP (integer)``
1194 Maximum quantization parameter for H264. Valid range: from 0 to 51.
1196 ``V4L2_CID_MPEG_VIDEO_H264_P_FRAME_QP (integer)``
1197 Quantization parameter for an P frame for H264. Valid range: from 0
1200 ``V4L2_CID_MPEG_VIDEO_H264_B_FRAME_QP (integer)``
1201 Quantization parameter for an B frame for H264. Valid range: from 0
1204 ``V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP (integer)``
1205 Quantization parameter for an I frame for MPEG4. Valid range: from 1
1208 ``V4L2_CID_MPEG_VIDEO_MPEG4_MIN_QP (integer)``
1209 Minimum quantization parameter for MPEG4. Valid range: from 1 to 31.
1211 ``V4L2_CID_MPEG_VIDEO_MPEG4_MAX_QP (integer)``
1212 Maximum quantization parameter for MPEG4. Valid range: from 1 to 31.
1214 ``V4L2_CID_MPEG_VIDEO_MPEG4_P_FRAME_QP (integer)``
1215 Quantization parameter for an P frame for MPEG4. Valid range: from 1
1218 ``V4L2_CID_MPEG_VIDEO_MPEG4_B_FRAME_QP (integer)``
1219 Quantization parameter for an B frame for MPEG4. Valid range: from 1
1222 ``V4L2_CID_MPEG_VIDEO_VBV_SIZE (integer)``
1223 The Video Buffer Verifier size in kilobytes, it is used as a
1224 limitation of frame skip. The VBV is defined in the standard as a
1225 mean to verify that the produced stream will be successfully
1226 decoded. The standard describes it as "Part of a hypothetical
1227 decoder that is conceptually connected to the output of the encoder.
1228 Its purpose is to provide a constraint on the variability of the
1229 data rate that an encoder or editing process may produce.".
1230 Applicable to the MPEG1, MPEG2, MPEG4 encoders.
1232 .. _v4l2-mpeg-video-vbv-delay:
1234 ``V4L2_CID_MPEG_VIDEO_VBV_DELAY (integer)``
1235 Sets the initial delay in milliseconds for VBV buffer control.
1237 .. _v4l2-mpeg-video-hor-search-range:
1239 ``V4L2_CID_MPEG_VIDEO_MV_H_SEARCH_RANGE (integer)``
1240 Horizontal search range defines maximum horizontal search area in
1241 pixels to search and match for the present Macroblock (MB) in the
1242 reference picture. This V4L2 control macro is used to set horizontal
1243 search range for motion estimation module in video encoder.
1245 .. _v4l2-mpeg-video-vert-search-range:
1247 ``V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE (integer)``
1248 Vertical search range defines maximum vertical search area in pixels
1249 to search and match for the present Macroblock (MB) in the reference
1250 picture. This V4L2 control macro is used to set vertical search
1251 range for motion estimation module in video encoder.
1253 .. _v4l2-mpeg-video-force-key-frame:
1255 ``V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME (button)``
1256 Force a key frame for the next queued buffer. Applicable to
1257 encoders. This is a general, codec-agnostic keyframe control.
1259 ``V4L2_CID_MPEG_VIDEO_H264_CPB_SIZE (integer)``
1260 The Coded Picture Buffer size in kilobytes, it is used as a
1261 limitation of frame skip. The CPB is defined in the H264 standard as
1262 a mean to verify that the produced stream will be successfully
1263 decoded. Applicable to the H264 encoder.
1265 ``V4L2_CID_MPEG_VIDEO_H264_I_PERIOD (integer)``
1266 Period between I-frames in the open GOP for H264. In case of an open
1267 GOP this is the period between two I-frames. The period between IDR
1268 (Instantaneous Decoding Refresh) frames is taken from the GOP_SIZE
1269 control. An IDR frame, which stands for Instantaneous Decoding
1270 Refresh is an I-frame after which no prior frames are referenced.
1271 This means that a stream can be restarted from an IDR frame without
1272 the need to store or decode any previous frames. Applicable to the
1275 .. _v4l2-mpeg-video-header-mode:
1277 ``V4L2_CID_MPEG_VIDEO_HEADER_MODE``
1280 enum v4l2_mpeg_video_header_mode -
1281 Determines whether the header is returned as the first buffer or is
1282 it returned together with the first frame. Applicable to encoders.
1283 Possible values are:
1287 .. tabularcolumns:: |p{10.3cm}|p{7.2cm}|
1293 * - ``V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE``
1294 - The stream header is returned separately in the first buffer.
1295 * - ``V4L2_MPEG_VIDEO_HEADER_MODE_JOINED_WITH_1ST_FRAME``
1296 - The stream header is returned together with the first encoded
1301 ``V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER (boolean)``
1302 Repeat the video sequence headers. Repeating these headers makes
1303 random access to the video stream easier. Applicable to the MPEG1, 2
1306 ``V4L2_CID_MPEG_VIDEO_DECODER_MPEG4_DEBLOCK_FILTER (boolean)``
1307 Enabled the deblocking post processing filter for MPEG4 decoder.
1308 Applicable to the MPEG4 decoder.
1310 ``V4L2_CID_MPEG_VIDEO_MPEG4_VOP_TIME_RES (integer)``
1311 vop_time_increment_resolution value for MPEG4. Applicable to the
1314 ``V4L2_CID_MPEG_VIDEO_MPEG4_VOP_TIME_INC (integer)``
1315 vop_time_increment value for MPEG4. Applicable to the MPEG4
1318 ``V4L2_CID_MPEG_VIDEO_H264_SEI_FRAME_PACKING (boolean)``
1319 Enable generation of frame packing supplemental enhancement
1320 information in the encoded bitstream. The frame packing SEI message
1321 contains the arrangement of L and R planes for 3D viewing.
1322 Applicable to the H264 encoder.
1324 ``V4L2_CID_MPEG_VIDEO_H264_SEI_FP_CURRENT_FRAME_0 (boolean)``
1325 Sets current frame as frame0 in frame packing SEI. Applicable to the
1328 .. _v4l2-mpeg-video-h264-sei-fp-arrangement-type:
1330 ``V4L2_CID_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE``
1333 enum v4l2_mpeg_video_h264_sei_fp_arrangement_type -
1334 Frame packing arrangement type for H264 SEI. Applicable to the H264
1335 encoder. Possible values are:
1337 .. tabularcolumns:: |p{12cm}|p{5.5cm}|
1343 * - ``V4L2_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE_CHEKERBOARD``
1344 - Pixels are alternatively from L and R.
1345 * - ``V4L2_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE_COLUMN``
1346 - L and R are interlaced by column.
1347 * - ``V4L2_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE_ROW``
1348 - L and R are interlaced by row.
1349 * - ``V4L2_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE_SIDE_BY_SIDE``
1350 - L is on the left, R on the right.
1351 * - ``V4L2_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE_TOP_BOTTOM``
1352 - L is on top, R on bottom.
1353 * - ``V4L2_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE_TEMPORAL``
1354 - One view per frame.
1358 ``V4L2_CID_MPEG_VIDEO_H264_FMO (boolean)``
1359 Enables flexible macroblock ordering in the encoded bitstream. It is
1360 a technique used for restructuring the ordering of macroblocks in
1361 pictures. Applicable to the H264 encoder.
1363 .. _v4l2-mpeg-video-h264-fmo-map-type:
1365 ``V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE``
1368 enum v4l2_mpeg_video_h264_fmo_map_type -
1369 When using FMO, the map type divides the image in different scan
1370 patterns of macroblocks. Applicable to the H264 encoder. Possible
1373 .. tabularcolumns:: |p{12.5cm}|p{5.0cm}|
1379 * - ``V4L2_MPEG_VIDEO_H264_FMO_MAP_TYPE_INTERLEAVED_SLICES``
1380 - Slices are interleaved one after other with macroblocks in run
1382 * - ``V4L2_MPEG_VIDEO_H264_FMO_MAP_TYPE_SCATTERED_SLICES``
1383 - Scatters the macroblocks based on a mathematical function known to
1384 both encoder and decoder.
1385 * - ``V4L2_MPEG_VIDEO_H264_FMO_MAP_TYPE_FOREGROUND_WITH_LEFT_OVER``
1386 - Macroblocks arranged in rectangular areas or regions of interest.
1387 * - ``V4L2_MPEG_VIDEO_H264_FMO_MAP_TYPE_BOX_OUT``
1388 - Slice groups grow in a cyclic way from centre to outwards.
1389 * - ``V4L2_MPEG_VIDEO_H264_FMO_MAP_TYPE_RASTER_SCAN``
1390 - Slice groups grow in raster scan pattern from left to right.
1391 * - ``V4L2_MPEG_VIDEO_H264_FMO_MAP_TYPE_WIPE_SCAN``
1392 - Slice groups grow in wipe scan pattern from top to bottom.
1393 * - ``V4L2_MPEG_VIDEO_H264_FMO_MAP_TYPE_EXPLICIT``
1394 - User defined map type.
1398 ``V4L2_CID_MPEG_VIDEO_H264_FMO_SLICE_GROUP (integer)``
1399 Number of slice groups in FMO. Applicable to the H264 encoder.
1401 .. _v4l2-mpeg-video-h264-fmo-change-direction:
1403 ``V4L2_CID_MPEG_VIDEO_H264_FMO_CHANGE_DIRECTION``
1406 enum v4l2_mpeg_video_h264_fmo_change_dir -
1407 Specifies a direction of the slice group change for raster and wipe
1408 maps. Applicable to the H264 encoder. Possible values are:
1416 * - ``V4L2_MPEG_VIDEO_H264_FMO_CHANGE_DIR_RIGHT``
1417 - Raster scan or wipe right.
1418 * - ``V4L2_MPEG_VIDEO_H264_FMO_CHANGE_DIR_LEFT``
1419 - Reverse raster scan or wipe left.
1423 ``V4L2_CID_MPEG_VIDEO_H264_FMO_CHANGE_RATE (integer)``
1424 Specifies the size of the first slice group for raster and wipe map.
1425 Applicable to the H264 encoder.
1427 ``V4L2_CID_MPEG_VIDEO_H264_FMO_RUN_LENGTH (integer)``
1428 Specifies the number of consecutive macroblocks for the interleaved
1429 map. Applicable to the H264 encoder.
1431 ``V4L2_CID_MPEG_VIDEO_H264_ASO (boolean)``
1432 Enables arbitrary slice ordering in encoded bitstream. Applicable to
1435 ``V4L2_CID_MPEG_VIDEO_H264_ASO_SLICE_ORDER (integer)``
1436 Specifies the slice order in ASO. Applicable to the H264 encoder.
1437 The supplied 32-bit integer is interpreted as follows (bit 0 = least
1449 - Slice position or order
1453 ``V4L2_CID_MPEG_VIDEO_H264_HIERARCHICAL_CODING (boolean)``
1454 Enables H264 hierarchical coding. Applicable to the H264 encoder.
1456 .. _v4l2-mpeg-video-h264-hierarchical-coding-type:
1458 ``V4L2_CID_MPEG_VIDEO_H264_HIERARCHICAL_CODING_TYPE``
1461 enum v4l2_mpeg_video_h264_hierarchical_coding_type -
1462 Specifies the hierarchical coding type. Applicable to the H264
1463 encoder. Possible values are:
1471 * - ``V4L2_MPEG_VIDEO_H264_HIERARCHICAL_CODING_B``
1472 - Hierarchical B coding.
1473 * - ``V4L2_MPEG_VIDEO_H264_HIERARCHICAL_CODING_P``
1474 - Hierarchical P coding.
1478 ``V4L2_CID_MPEG_VIDEO_H264_HIERARCHICAL_CODING_LAYER (integer)``
1479 Specifies the number of hierarchical coding layers. Applicable to
1482 ``V4L2_CID_MPEG_VIDEO_H264_HIERARCHICAL_CODING_LAYER_QP (integer)``
1483 Specifies a user defined QP for each layer. Applicable to the H264
1484 encoder. The supplied 32-bit integer is interpreted as follows (bit
1485 0 = least significant bit):
1501 MFC 5.1 MPEG Controls
1502 ---------------------
1504 The following MPEG class controls deal with MPEG decoding and encoding
1505 settings that are specific to the Multi Format Codec 5.1 device present
1506 in the S5P family of SoCs by Samsung.
1509 .. _mfc51-control-id:
1514 ``V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY_ENABLE (boolean)``
1515 If the display delay is enabled then the decoder is forced to return
1516 a CAPTURE buffer (decoded frame) after processing a certain number
1517 of OUTPUT buffers. The delay can be set through
1518 ``V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY``. This
1519 feature can be used for example for generating thumbnails of videos.
1520 Applicable to the H264 decoder.
1522 ``V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY (integer)``
1523 Display delay value for H264 decoder. The decoder is forced to
1524 return a decoded frame after the set 'display delay' number of
1525 frames. If this number is low it may result in frames returned out
1526 of dispaly order, in addition the hardware may still be using the
1527 returned buffer as a reference picture for subsequent frames.
1529 ``V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P (integer)``
1530 The number of reference pictures used for encoding a P picture.
1531 Applicable to the H264 encoder.
1533 ``V4L2_CID_MPEG_MFC51_VIDEO_PADDING (boolean)``
1534 Padding enable in the encoder - use a color instead of repeating
1535 border pixels. Applicable to encoders.
1537 ``V4L2_CID_MPEG_MFC51_VIDEO_PADDING_YUV (integer)``
1538 Padding color in the encoder. Applicable to encoders. The supplied
1539 32-bit integer is interpreted as follows (bit 0 = least significant
1549 - V chrominance information
1551 - U chrominance information
1553 - Y luminance information
1559 ``V4L2_CID_MPEG_MFC51_VIDEO_RC_REACTION_COEFF (integer)``
1560 Reaction coefficient for MFC rate control. Applicable to encoders.
1564 #. Valid only when the frame level RC is enabled.
1566 #. For tight CBR, this field must be small (ex. 2 ~ 10). For
1567 VBR, this field must be large (ex. 100 ~ 1000).
1569 #. It is not recommended to use the greater number than
1570 FRAME_RATE * (10^9 / BIT_RATE).
1572 ``V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_DARK (boolean)``
1573 Adaptive rate control for dark region. Valid only when H.264 and
1574 macroblock level RC is enabled
1575 (``V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE``). Applicable to the H264
1578 ``V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_SMOOTH (boolean)``
1579 Adaptive rate control for smooth region. Valid only when H.264 and
1580 macroblock level RC is enabled
1581 (``V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE``). Applicable to the H264
1584 ``V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_STATIC (boolean)``
1585 Adaptive rate control for static region. Valid only when H.264 and
1586 macroblock level RC is enabled
1587 (``V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE``). Applicable to the H264
1590 ``V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_ACTIVITY (boolean)``
1591 Adaptive rate control for activity region. Valid only when H.264 and
1592 macroblock level RC is enabled
1593 (``V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE``). Applicable to the H264
1596 .. _v4l2-mpeg-mfc51-video-frame-skip-mode:
1598 ``V4L2_CID_MPEG_MFC51_VIDEO_FRAME_SKIP_MODE``
1601 enum v4l2_mpeg_mfc51_video_frame_skip_mode -
1602 Indicates in what conditions the encoder should skip frames. If
1603 encoding a frame would cause the encoded stream to be larger then a
1604 chosen data limit then the frame will be skipped. Possible values
1608 .. tabularcolumns:: |p{9.0cm}|p{8.5cm}|
1614 * - ``V4L2_MPEG_MFC51_FRAME_SKIP_MODE_DISABLED``
1615 - Frame skip mode is disabled.
1616 * - ``V4L2_MPEG_MFC51_FRAME_SKIP_MODE_LEVEL_LIMIT``
1617 - Frame skip mode enabled and buffer limit is set by the chosen
1618 level and is defined by the standard.
1619 * - ``V4L2_MPEG_MFC51_FRAME_SKIP_MODE_BUF_LIMIT``
1620 - Frame skip mode enabled and buffer limit is set by the VBV
1621 (MPEG1/2/4) or CPB (H264) buffer size control.
1625 ``V4L2_CID_MPEG_MFC51_VIDEO_RC_FIXED_TARGET_BIT (integer)``
1626 Enable rate-control with fixed target bit. If this setting is
1627 enabled, then the rate control logic of the encoder will calculate
1628 the average bitrate for a GOP and keep it below or equal the set
1629 bitrate target. Otherwise the rate control logic calculates the
1630 overall average bitrate for the stream and keeps it below or equal
1631 to the set bitrate. In the first case the average bitrate for the
1632 whole stream will be smaller then the set bitrate. This is caused
1633 because the average is calculated for smaller number of frames, on
1634 the other hand enabling this setting will ensure that the stream
1635 will meet tight bandwidth constraints. Applicable to encoders.
1637 .. _v4l2-mpeg-mfc51-video-force-frame-type:
1639 ``V4L2_CID_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE``
1642 enum v4l2_mpeg_mfc51_video_force_frame_type -
1643 Force a frame type for the next queued buffer. Applicable to
1644 encoders. Possible values are:
1652 * - ``V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_DISABLED``
1653 - Forcing a specific frame type disabled.
1654 * - ``V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_I_FRAME``
1656 * - ``V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_NOT_CODED``
1657 - Force a non-coded frame.
1662 CX2341x MPEG Controls
1663 ---------------------
1665 The following MPEG class controls deal with MPEG encoding settings that
1666 are specific to the Conexant CX23415 and CX23416 MPEG encoding chips.
1669 .. _cx2341x-control-id:
1674 .. _v4l2-mpeg-cx2341x-video-spatial-filter-mode:
1676 ``V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE``
1679 enum v4l2_mpeg_cx2341x_video_spatial_filter_mode -
1680 Sets the Spatial Filter mode (default ``MANUAL``). Possible values
1689 * - ``V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_MANUAL``
1690 - Choose the filter manually
1691 * - ``V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_AUTO``
1692 - Choose the filter automatically
1696 ``V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER (integer (0-15))``
1697 The setting for the Spatial Filter. 0 = off, 15 = maximum. (Default
1700 .. _luma-spatial-filter-type:
1702 ``V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE``
1705 enum v4l2_mpeg_cx2341x_video_luma_spatial_filter_type -
1706 Select the algorithm to use for the Luma Spatial Filter (default
1707 ``1D_HOR``). Possible values:
1711 .. tabularcolumns:: |p{14.5cm}|p{3.0cm}|
1717 * - ``V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_OFF``
1719 * - ``V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_HOR``
1720 - One-dimensional horizontal
1721 * - ``V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_VERT``
1722 - One-dimensional vertical
1723 * - ``V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_HV_SEPARABLE``
1724 - Two-dimensional separable
1725 * - ``V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_SYM_NON_SEPARABLE``
1726 - Two-dimensional symmetrical non-separable
1730 .. _chroma-spatial-filter-type:
1732 ``V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE``
1735 enum v4l2_mpeg_cx2341x_video_chroma_spatial_filter_type -
1736 Select the algorithm for the Chroma Spatial Filter (default
1737 ``1D_HOR``). Possible values are:
1745 * - ``V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_OFF``
1747 * - ``V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_1D_HOR``
1748 - One-dimensional horizontal
1752 .. _v4l2-mpeg-cx2341x-video-temporal-filter-mode:
1754 ``V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE``
1757 enum v4l2_mpeg_cx2341x_video_temporal_filter_mode -
1758 Sets the Temporal Filter mode (default ``MANUAL``). Possible values
1767 * - ``V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_MANUAL``
1768 - Choose the filter manually
1769 * - ``V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_AUTO``
1770 - Choose the filter automatically
1774 ``V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER (integer (0-31))``
1775 The setting for the Temporal Filter. 0 = off, 31 = maximum. (Default
1776 is 8 for full-scale capturing and 0 for scaled capturing.)
1778 .. _v4l2-mpeg-cx2341x-video-median-filter-type:
1780 ``V4L2_CID_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE``
1783 enum v4l2_mpeg_cx2341x_video_median_filter_type -
1784 Median Filter Type (default ``OFF``). Possible values are:
1792 * - ``V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_OFF``
1794 * - ``V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR``
1796 * - ``V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_VERT``
1798 * - ``V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR_VERT``
1799 - Horizontal and vertical filter
1800 * - ``V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_DIAG``
1805 ``V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_BOTTOM (integer (0-255))``
1806 Threshold above which the luminance median filter is enabled
1809 ``V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_TOP (integer (0-255))``
1810 Threshold below which the luminance median filter is enabled
1813 ``V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_BOTTOM (integer (0-255))``
1814 Threshold above which the chroma median filter is enabled (default
1817 ``V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_TOP (integer (0-255))``
1818 Threshold below which the chroma median filter is enabled (default
1821 ``V4L2_CID_MPEG_CX2341X_STREAM_INSERT_NAV_PACKETS (boolean)``
1822 The CX2341X MPEG encoder can insert one empty MPEG-2 PES packet into
1823 the stream between every four video frames. The packet size is 2048
1824 bytes, including the packet_start_code_prefix and stream_id
1825 fields. The stream_id is 0xBF (private stream 2). The payload
1826 consists of 0x00 bytes, to be filled in by the application. 0 = do
1827 not insert, 1 = insert packets.
1830 VPX Control Reference
1831 ---------------------
1833 The VPX controls include controls for encoding parameters of VPx video
1842 .. _v4l2-vpx-num-partitions:
1844 ``V4L2_CID_MPEG_VIDEO_VPX_NUM_PARTITIONS``
1847 enum v4l2_vp8_num_partitions -
1848 The number of token partitions to use in VP8 encoder. Possible
1857 * - ``V4L2_CID_MPEG_VIDEO_VPX_1_PARTITION``
1858 - 1 coefficient partition
1859 * - ``V4L2_CID_MPEG_VIDEO_VPX_2_PARTITIONS``
1860 - 2 coefficient partitions
1861 * - ``V4L2_CID_MPEG_VIDEO_VPX_4_PARTITIONS``
1862 - 4 coefficient partitions
1863 * - ``V4L2_CID_MPEG_VIDEO_VPX_8_PARTITIONS``
1864 - 8 coefficient partitions
1868 ``V4L2_CID_MPEG_VIDEO_VPX_IMD_DISABLE_4X4 (boolean)``
1869 Setting this prevents intra 4x4 mode in the intra mode decision.
1871 .. _v4l2-vpx-num-ref-frames:
1873 ``V4L2_CID_MPEG_VIDEO_VPX_NUM_REF_FRAMES``
1876 enum v4l2_vp8_num_ref_frames -
1877 The number of reference pictures for encoding P frames. Possible
1880 .. tabularcolumns:: |p{7.9cm}|p{9.6cm}|
1886 * - ``V4L2_CID_MPEG_VIDEO_VPX_1_REF_FRAME``
1887 - Last encoded frame will be searched
1888 * - ``V4L2_CID_MPEG_VIDEO_VPX_2_REF_FRAME``
1889 - Two frames will be searched among the last encoded frame, the
1890 golden frame and the alternate reference (altref) frame. The
1891 encoder implementation will decide which two are chosen.
1892 * - ``V4L2_CID_MPEG_VIDEO_VPX_3_REF_FRAME``
1893 - The last encoded frame, the golden frame and the altref frame will
1898 ``V4L2_CID_MPEG_VIDEO_VPX_FILTER_LEVEL (integer)``
1899 Indicates the loop filter level. The adjustment of the loop filter
1900 level is done via a delta value against a baseline loop filter
1903 ``V4L2_CID_MPEG_VIDEO_VPX_FILTER_SHARPNESS (integer)``
1904 This parameter affects the loop filter. Anything above zero weakens
1905 the deblocking effect on the loop filter.
1907 ``V4L2_CID_MPEG_VIDEO_VPX_GOLDEN_FRAME_REF_PERIOD (integer)``
1908 Sets the refresh period for the golden frame. The period is defined
1909 in number of frames. For a value of 'n', every nth frame starting
1910 from the first key frame will be taken as a golden frame. For eg.
1911 for encoding sequence of 0, 1, 2, 3, 4, 5, 6, 7 where the golden
1912 frame refresh period is set as 4, the frames 0, 4, 8 etc will be
1913 taken as the golden frames as frame 0 is always a key frame.
1915 .. _v4l2-vpx-golden-frame-sel:
1917 ``V4L2_CID_MPEG_VIDEO_VPX_GOLDEN_FRAME_SEL``
1920 enum v4l2_vp8_golden_frame_sel -
1921 Selects the golden frame for encoding. Possible values are:
1927 .. tabularcolumns:: |p{9.0cm}|p{8.0cm}|
1933 * - ``V4L2_CID_MPEG_VIDEO_VPX_GOLDEN_FRAME_USE_PREV``
1934 - Use the (n-2)th frame as a golden frame, current frame index being
1936 * - ``V4L2_CID_MPEG_VIDEO_VPX_GOLDEN_FRAME_USE_REF_PERIOD``
1937 - Use the previous specific frame indicated by
1938 ``V4L2_CID_MPEG_VIDEO_VPX_GOLDEN_FRAME_REF_PERIOD`` as a
1946 ``V4L2_CID_MPEG_VIDEO_VPX_MIN_QP (integer)``
1947 Minimum quantization parameter for VP8.
1949 ``V4L2_CID_MPEG_VIDEO_VPX_MAX_QP (integer)``
1950 Maximum quantization parameter for VP8.
1952 ``V4L2_CID_MPEG_VIDEO_VPX_I_FRAME_QP (integer)``
1953 Quantization parameter for an I frame for VP8.
1955 ``V4L2_CID_MPEG_VIDEO_VPX_P_FRAME_QP (integer)``
1956 Quantization parameter for a P frame for VP8.
1958 ``V4L2_CID_MPEG_VIDEO_VPX_PROFILE (integer)``
1959 Select the desired profile for VPx encoder. Acceptable values are 0,
1960 1, 2 and 3 corresponding to encoder profiles 0, 1, 2 and 3.
1963 High Efficiency Video Coding (HEVC/H.265) Control Reference
1964 -----------------------------------------------------------
1966 The HEVC/H.265 controls include controls for encoding parameters of HEVC/H.265
1970 .. _hevc-control-id:
1972 HEVC/H.265 Control IDs
1973 ^^^^^^^^^^^^^^^^^^^^^^
1975 ``V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP (integer)``
1976 Minimum quantization parameter for HEVC.
1977 Valid range: from 0 to 51.
1979 ``V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP (integer)``
1980 Maximum quantization parameter for HEVC.
1981 Valid range: from 0 to 51.
1983 ``V4L2_CID_MPEG_VIDEO_HEVC_I_FRAME_QP (integer)``
1984 Quantization parameter for an I frame for HEVC.
1985 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
1986 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
1988 ``V4L2_CID_MPEG_VIDEO_HEVC_P_FRAME_QP (integer)``
1989 Quantization parameter for a P frame for HEVC.
1990 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
1991 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
1993 ``V4L2_CID_MPEG_VIDEO_HEVC_B_FRAME_QP (integer)``
1994 Quantization parameter for a B frame for HEVC.
1995 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
1996 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
1998 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_QP (boolean)``
1999 HIERARCHICAL_QP allows the host to specify the quantization parameter
2000 values for each temporal layer through HIERARCHICAL_QP_LAYER. This is
2001 valid only if HIERARCHICAL_CODING_LAYER is greater than 1. Setting the
2002 control value to 1 enables setting of the QP values for the layers.
2004 .. _v4l2-hevc-hier-coding-type:
2006 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_TYPE``
2009 enum v4l2_mpeg_video_hevc_hier_coding_type -
2010 Selects the hierarchical coding type for encoding. Possible values are:
2016 .. tabularcolumns:: |p{9.0cm}|p{8.0cm}|
2022 * - ``V4L2_MPEG_VIDEO_HEVC_HIERARCHICAL_CODING_B``
2023 - Use the B frame for hierarchical coding.
2024 * - ``V4L2_MPEG_VIDEO_HEVC_HIERARCHICAL_CODING_P``
2025 - Use the P frame for hierarchical coding.
2032 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_LAYER (integer)``
2033 Selects the hierarchical coding layer. In normal encoding
2034 (non-hierarchial coding), it should be zero. Possible values are [0, 6].
2035 0 indicates HIERARCHICAL CODING LAYER 0, 1 indicates HIERARCHICAL CODING
2038 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L0_QP (integer)``
2039 Indicates quantization parameter for hierarchical coding layer 0.
2040 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
2041 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
2043 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L1_QP (integer)``
2044 Indicates quantization parameter for hierarchical coding layer 1.
2045 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
2046 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
2048 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L2_QP (integer)``
2049 Indicates quantization parameter for hierarchical coding layer 2.
2050 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
2051 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
2053 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L3_QP (integer)``
2054 Indicates quantization parameter for hierarchical coding layer 3.
2055 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
2056 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
2058 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L4_QP (integer)``
2059 Indicates quantization parameter for hierarchical coding layer 4.
2060 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
2061 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
2063 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_QP (integer)``
2064 Indicates quantization parameter for hierarchical coding layer 5.
2065 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
2066 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
2068 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L6_QP (integer)``
2069 Indicates quantization parameter for hierarchical coding layer 6.
2070 Valid range: [V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP,
2071 V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP].
2073 .. _v4l2-hevc-profile:
2075 ``V4L2_CID_MPEG_VIDEO_HEVC_PROFILE``
2078 enum v4l2_mpeg_video_hevc_profile -
2079 Select the desired profile for HEVC encoder.
2085 .. tabularcolumns:: |p{9.0cm}|p{8.0cm}|
2091 * - ``V4L2_MPEG_VIDEO_HEVC_PROFILE_MAIN``
2093 * - ``V4L2_MPEG_VIDEO_HEVC_PROFILE_MAIN_STILL_PICTURE``
2094 - Main still picture profile.
2095 * - ``V4L2_MPEG_VIDEO_HEVC_PROFILE_MAIN_10``
2103 .. _v4l2-hevc-level:
2105 ``V4L2_CID_MPEG_VIDEO_HEVC_LEVEL``
2108 enum v4l2_mpeg_video_hevc_level -
2109 Selects the desired level for HEVC encoder.
2115 .. tabularcolumns:: |p{9.0cm}|p{8.0cm}|
2121 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_1``
2123 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_2``
2125 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_2_1``
2127 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_3``
2129 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_3_1``
2131 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_4``
2133 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_4_1``
2135 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_5``
2137 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_5_1``
2139 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_5_2``
2141 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_6``
2143 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_6_1``
2145 * - ``V4L2_MPEG_VIDEO_HEVC_LEVEL_6_2``
2153 ``V4L2_CID_MPEG_VIDEO_HEVC_FRAME_RATE_RESOLUTION (integer)``
2154 Indicates the number of evenly spaced subintervals, called ticks, within
2155 one second. This is a 16 bit unsigned integer and has a maximum value up to
2156 0xffff and a minimum value of 1.
2160 ``V4L2_CID_MPEG_VIDEO_HEVC_TIER``
2163 enum v4l2_mpeg_video_hevc_tier -
2164 TIER_FLAG specifies tiers information of the HEVC encoded picture. Tier
2165 were made to deal with applications that differ in terms of maximum bit
2166 rate. Setting the flag to 0 selects HEVC tier as Main tier and setting
2167 this flag to 1 indicates High tier. High tier is for applications requiring
2174 .. tabularcolumns:: |p{9.0cm}|p{8.0cm}|
2180 * - ``V4L2_MPEG_VIDEO_HEVC_TIER_MAIN``
2182 * - ``V4L2_MPEG_VIDEO_HEVC_TIER_HIGH``
2190 ``V4L2_CID_MPEG_VIDEO_HEVC_MAX_PARTITION_DEPTH (integer)``
2191 Selects HEVC maximum coding unit depth.
2193 .. _v4l2-hevc-loop-filter-mode:
2195 ``V4L2_CID_MPEG_VIDEO_HEVC_LOOP_FILTER_MODE``
2198 enum v4l2_mpeg_video_hevc_loop_filter_mode -
2199 Loop filter mode for HEVC encoder. Possible values are:
2205 .. tabularcolumns:: |p{10.7cm}|p{6.3cm}|
2211 * - ``V4L2_MPEG_VIDEO_HEVC_LOOP_FILTER_MODE_DISABLED``
2212 - Loop filter is disabled.
2213 * - ``V4L2_MPEG_VIDEO_HEVC_LOOP_FILTER_MODE_ENABLED``
2214 - Loop filter is enabled.
2215 * - ``V4L2_MPEG_VIDEO_HEVC_LOOP_FILTER_MODE_DISABLED_AT_SLICE_BOUNDARY``
2216 - Loop filter is disabled at the slice boundary.
2223 ``V4L2_CID_MPEG_VIDEO_HEVC_LF_BETA_OFFSET_DIV2 (integer)``
2224 Selects HEVC loop filter beta offset. The valid range is [-6, +6].
2226 ``V4L2_CID_MPEG_VIDEO_HEVC_LF_TC_OFFSET_DIV2 (integer)``
2227 Selects HEVC loop filter tc offset. The valid range is [-6, +6].
2229 .. _v4l2-hevc-refresh-type:
2231 ``V4L2_CID_MPEG_VIDEO_HEVC_REFRESH_TYPE``
2234 enum v4l2_mpeg_video_hevc_hier_refresh_type -
2235 Selects refresh type for HEVC encoder.
2236 Host has to specify the period into
2237 V4L2_CID_MPEG_VIDEO_HEVC_REFRESH_PERIOD.
2243 .. tabularcolumns:: |p{8.0cm}|p{9.0cm}|
2249 * - ``V4L2_MPEG_VIDEO_HEVC_REFRESH_NONE``
2250 - Use the B frame for hierarchical coding.
2251 * - ``V4L2_MPEG_VIDEO_HEVC_REFRESH_CRA``
2252 - Use CRA (Clean Random Access Unit) picture encoding.
2253 * - ``V4L2_MPEG_VIDEO_HEVC_REFRESH_IDR``
2254 - Use IDR (Instantaneous Decoding Refresh) picture encoding.
2261 ``V4L2_CID_MPEG_VIDEO_HEVC_REFRESH_PERIOD (integer)``
2262 Selects the refresh period for HEVC encoder.
2263 This specifies the number of I pictures between two CRA/IDR pictures.
2264 This is valid only if REFRESH_TYPE is not 0.
2266 ``V4L2_CID_MPEG_VIDEO_HEVC_LOSSLESS_CU (boolean)``
2267 Indicates HEVC lossless encoding. Setting it to 0 disables lossless
2268 encoding. Setting it to 1 enables lossless encoding.
2270 ``V4L2_CID_MPEG_VIDEO_HEVC_CONST_INTRA_PRED (boolean)``
2271 Indicates constant intra prediction for HEVC encoder. Specifies the
2272 constrained intra prediction in which intra largest coding unit (LCU)
2273 prediction is performed by using residual data and decoded samples of
2274 neighboring intra LCU only. Setting the value to 1 enables constant intra
2275 prediction and setting the value to 0 disables constant intra prediction.
2277 ``V4L2_CID_MPEG_VIDEO_HEVC_WAVEFRONT (boolean)``
2278 Indicates wavefront parallel processing for HEVC encoder. Setting it to 0
2279 disables the feature and setting it to 1 enables the wavefront parallel
2282 ``V4L2_CID_MPEG_VIDEO_HEVC_GENERAL_PB (boolean)``
2283 Setting the value to 1 enables combination of P and B frame for HEVC
2286 ``V4L2_CID_MPEG_VIDEO_HEVC_TEMPORAL_ID (boolean)``
2287 Indicates temporal identifier for HEVC encoder which is enabled by
2288 setting the value to 1.
2290 ``V4L2_CID_MPEG_VIDEO_HEVC_STRONG_SMOOTHING (boolean)``
2291 Indicates bi-linear interpolation is conditionally used in the intra
2292 prediction filtering process in the CVS when set to 1. Indicates bi-linear
2293 interpolation is not used in the CVS when set to 0.
2295 ``V4L2_CID_MPEG_VIDEO_HEVC_MAX_NUM_MERGE_MV_MINUS1 (integer)``
2296 Indicates maximum number of merge candidate motion vectors.
2297 Values are from 0 to 4.
2299 ``V4L2_CID_MPEG_VIDEO_HEVC_TMV_PREDICTION (boolean)``
2300 Indicates temporal motion vector prediction for HEVC encoder. Setting it to
2301 1 enables the prediction. Setting it to 0 disables the prediction.
2303 ``V4L2_CID_MPEG_VIDEO_HEVC_WITHOUT_STARTCODE (boolean)``
2304 Specifies if HEVC generates a stream with a size of the length field
2305 instead of start code pattern. The size of the length field is configurable
2306 through the V4L2_CID_MPEG_VIDEO_HEVC_SIZE_OF_LENGTH_FIELD control. Setting
2307 the value to 0 disables encoding without startcode pattern. Setting the
2308 value to 1 will enables encoding without startcode pattern.
2310 .. _v4l2-hevc-size-of-length-field:
2312 ``V4L2_CID_MPEG_VIDEO_HEVC_SIZE_OF_LENGTH_FIELD``
2315 enum v4l2_mpeg_video_hevc_size_of_length_field -
2316 Indicates the size of length field.
2317 This is valid when encoding WITHOUT_STARTCODE_ENABLE is enabled.
2323 .. tabularcolumns:: |p{6.0cm}|p{11.0cm}|
2329 * - ``V4L2_MPEG_VIDEO_HEVC_SIZE_0``
2330 - Generate start code pattern (Normal).
2331 * - ``V4L2_MPEG_VIDEO_HEVC_SIZE_1``
2332 - Generate size of length field instead of start code pattern and length is 1.
2333 * - ``V4L2_MPEG_VIDEO_HEVC_SIZE_2``
2334 - Generate size of length field instead of start code pattern and length is 2.
2335 * - ``V4L2_MPEG_VIDEO_HEVC_SIZE_4``
2336 - Generate size of length field instead of start code pattern and length is 4.
2342 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L0_BR (integer)``
2343 Indicates bit rate for hierarchical coding layer 0 for HEVC encoder.
2345 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L1_BR (integer)``
2346 Indicates bit rate for hierarchical coding layer 1 for HEVC encoder.
2348 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L2_BR (integer)``
2349 Indicates bit rate for hierarchical coding layer 2 for HEVC encoder.
2351 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L3_BR (integer)``
2352 Indicates bit rate for hierarchical coding layer 3 for HEVC encoder.
2354 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L4_BR (integer)``
2355 Indicates bit rate for hierarchical coding layer 4 for HEVC encoder.
2357 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR (integer)``
2358 Indicates bit rate for hierarchical coding layer 5 for HEVC encoder.
2360 ``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L6_BR (integer)``
2361 Indicates bit rate for hierarchical coding layer 6 for HEVC encoder.
2363 ``V4L2_CID_MPEG_VIDEO_REF_NUMBER_FOR_PFRAMES (integer)``
2364 Selects number of P reference pictures required for HEVC encoder.
2365 P-Frame can use 1 or 2 frames for reference.
2367 ``V4L2_CID_MPEG_VIDEO_PREPEND_SPSPPS_TO_IDR (integer)``
2368 Indicates whether to generate SPS and PPS at every IDR. Setting it to 0
2369 disables generating SPS and PPS at every IDR. Setting it to one enables
2370 generating SPS and PPS at every IDR.
2373 .. _camera-controls:
2375 Camera Control Reference
2376 ========================
2378 The Camera class includes controls for mechanical (or equivalent
2379 digital) features of a device such as controllable lenses or sensors.
2382 .. _camera-control-id:
2387 ``V4L2_CID_CAMERA_CLASS (class)``
2388 The Camera class descriptor. Calling
2389 :ref:`VIDIOC_QUERYCTRL` for this control will
2390 return a description of this control class.
2392 .. _v4l2-exposure-auto-type:
2394 ``V4L2_CID_EXPOSURE_AUTO``
2397 enum v4l2_exposure_auto_type -
2398 Enables automatic adjustments of the exposure time and/or iris
2399 aperture. The effect of manual changes of the exposure time or iris
2400 aperture while these features are enabled is undefined, drivers
2401 should ignore such requests. Possible values are:
2409 * - ``V4L2_EXPOSURE_AUTO``
2410 - Automatic exposure time, automatic iris aperture.
2411 * - ``V4L2_EXPOSURE_MANUAL``
2412 - Manual exposure time, manual iris.
2413 * - ``V4L2_EXPOSURE_SHUTTER_PRIORITY``
2414 - Manual exposure time, auto iris.
2415 * - ``V4L2_EXPOSURE_APERTURE_PRIORITY``
2416 - Auto exposure time, manual iris.
2420 ``V4L2_CID_EXPOSURE_ABSOLUTE (integer)``
2421 Determines the exposure time of the camera sensor. The exposure time
2422 is limited by the frame interval. Drivers should interpret the
2423 values as 100 µs units, where the value 1 stands for 1/10000th of a
2424 second, 10000 for 1 second and 100000 for 10 seconds.
2426 ``V4L2_CID_EXPOSURE_AUTO_PRIORITY (boolean)``
2427 When ``V4L2_CID_EXPOSURE_AUTO`` is set to ``AUTO`` or
2428 ``APERTURE_PRIORITY``, this control determines if the device may
2429 dynamically vary the frame rate. By default this feature is disabled
2430 (0) and the frame rate must remain constant.
2432 ``V4L2_CID_AUTO_EXPOSURE_BIAS (integer menu)``
2433 Determines the automatic exposure compensation, it is effective only
2434 when ``V4L2_CID_EXPOSURE_AUTO`` control is set to ``AUTO``,
2435 ``SHUTTER_PRIORITY`` or ``APERTURE_PRIORITY``. It is expressed in
2436 terms of EV, drivers should interpret the values as 0.001 EV units,
2437 where the value 1000 stands for +1 EV.
2439 Increasing the exposure compensation value is equivalent to
2440 decreasing the exposure value (EV) and will increase the amount of
2441 light at the image sensor. The camera performs the exposure
2442 compensation by adjusting absolute exposure time and/or aperture.
2444 .. _v4l2-exposure-metering:
2446 ``V4L2_CID_EXPOSURE_METERING``
2449 enum v4l2_exposure_metering -
2450 Determines how the camera measures the amount of light available for
2451 the frame exposure. Possible values are:
2453 .. tabularcolumns:: |p{8.5cm}|p{9.0cm}|
2459 * - ``V4L2_EXPOSURE_METERING_AVERAGE``
2460 - Use the light information coming from the entire frame and average
2461 giving no weighting to any particular portion of the metered area.
2462 * - ``V4L2_EXPOSURE_METERING_CENTER_WEIGHTED``
2463 - Average the light information coming from the entire frame giving
2464 priority to the center of the metered area.
2465 * - ``V4L2_EXPOSURE_METERING_SPOT``
2466 - Measure only very small area at the center of the frame.
2467 * - ``V4L2_EXPOSURE_METERING_MATRIX``
2468 - A multi-zone metering. The light intensity is measured in several
2469 points of the frame and the results are combined. The algorithm of
2470 the zones selection and their significance in calculating the
2471 final value is device dependent.
2475 ``V4L2_CID_PAN_RELATIVE (integer)``
2476 This control turns the camera horizontally by the specified amount.
2477 The unit is undefined. A positive value moves the camera to the
2478 right (clockwise when viewed from above), a negative value to the
2479 left. A value of zero does not cause motion. This is a write-only
2482 ``V4L2_CID_TILT_RELATIVE (integer)``
2483 This control turns the camera vertically by the specified amount.
2484 The unit is undefined. A positive value moves the camera up, a
2485 negative value down. A value of zero does not cause motion. This is
2486 a write-only control.
2488 ``V4L2_CID_PAN_RESET (button)``
2489 When this control is set, the camera moves horizontally to the
2492 ``V4L2_CID_TILT_RESET (button)``
2493 When this control is set, the camera moves vertically to the default
2496 ``V4L2_CID_PAN_ABSOLUTE (integer)``
2497 This control turns the camera horizontally to the specified
2498 position. Positive values move the camera to the right (clockwise
2499 when viewed from above), negative values to the left. Drivers should
2500 interpret the values as arc seconds, with valid values between -180
2501 * 3600 and +180 * 3600 inclusive.
2503 ``V4L2_CID_TILT_ABSOLUTE (integer)``
2504 This control turns the camera vertically to the specified position.
2505 Positive values move the camera up, negative values down. Drivers
2506 should interpret the values as arc seconds, with valid values
2507 between -180 * 3600 and +180 * 3600 inclusive.
2509 ``V4L2_CID_FOCUS_ABSOLUTE (integer)``
2510 This control sets the focal point of the camera to the specified
2511 position. The unit is undefined. Positive values set the focus
2512 closer to the camera, negative values towards infinity.
2514 ``V4L2_CID_FOCUS_RELATIVE (integer)``
2515 This control moves the focal point of the camera by the specified
2516 amount. The unit is undefined. Positive values move the focus closer
2517 to the camera, negative values towards infinity. This is a
2520 ``V4L2_CID_FOCUS_AUTO (boolean)``
2521 Enables continuous automatic focus adjustments. The effect of manual
2522 focus adjustments while this feature is enabled is undefined,
2523 drivers should ignore such requests.
2525 ``V4L2_CID_AUTO_FOCUS_START (button)``
2526 Starts single auto focus process. The effect of setting this control
2527 when ``V4L2_CID_FOCUS_AUTO`` is set to ``TRUE`` (1) is undefined,
2528 drivers should ignore such requests.
2530 ``V4L2_CID_AUTO_FOCUS_STOP (button)``
2531 Aborts automatic focusing started with ``V4L2_CID_AUTO_FOCUS_START``
2532 control. It is effective only when the continuous autofocus is
2533 disabled, that is when ``V4L2_CID_FOCUS_AUTO`` control is set to
2536 .. _v4l2-auto-focus-status:
2538 ``V4L2_CID_AUTO_FOCUS_STATUS (bitmask)``
2539 The automatic focus status. This is a read-only control.
2541 Setting ``V4L2_LOCK_FOCUS`` lock bit of the ``V4L2_CID_3A_LOCK``
2542 control may stop updates of the ``V4L2_CID_AUTO_FOCUS_STATUS``
2545 .. tabularcolumns:: |p{6.5cm}|p{11.0cm}|
2551 * - ``V4L2_AUTO_FOCUS_STATUS_IDLE``
2552 - Automatic focus is not active.
2553 * - ``V4L2_AUTO_FOCUS_STATUS_BUSY``
2554 - Automatic focusing is in progress.
2555 * - ``V4L2_AUTO_FOCUS_STATUS_REACHED``
2556 - Focus has been reached.
2557 * - ``V4L2_AUTO_FOCUS_STATUS_FAILED``
2558 - Automatic focus has failed, the driver will not transition from
2559 this state until another action is performed by an application.
2563 .. _v4l2-auto-focus-range:
2565 ``V4L2_CID_AUTO_FOCUS_RANGE``
2568 enum v4l2_auto_focus_range -
2569 Determines auto focus distance range for which lens may be adjusted.
2571 .. tabularcolumns:: |p{6.5cm}|p{11.0cm}|
2577 * - ``V4L2_AUTO_FOCUS_RANGE_AUTO``
2578 - The camera automatically selects the focus range.
2579 * - ``V4L2_AUTO_FOCUS_RANGE_NORMAL``
2580 - Normal distance range, limited for best automatic focus
2582 * - ``V4L2_AUTO_FOCUS_RANGE_MACRO``
2583 - Macro (close-up) auto focus. The camera will use its minimum
2584 possible distance for auto focus.
2585 * - ``V4L2_AUTO_FOCUS_RANGE_INFINITY``
2586 - The lens is set to focus on an object at infinite distance.
2590 ``V4L2_CID_ZOOM_ABSOLUTE (integer)``
2591 Specify the objective lens focal length as an absolute value. The
2592 zoom unit is driver-specific and its value should be a positive
2595 ``V4L2_CID_ZOOM_RELATIVE (integer)``
2596 Specify the objective lens focal length relatively to the current
2597 value. Positive values move the zoom lens group towards the
2598 telephoto direction, negative values towards the wide-angle
2599 direction. The zoom unit is driver-specific. This is a write-only
2602 ``V4L2_CID_ZOOM_CONTINUOUS (integer)``
2603 Move the objective lens group at the specified speed until it
2604 reaches physical device limits or until an explicit request to stop
2605 the movement. A positive value moves the zoom lens group towards the
2606 telephoto direction. A value of zero stops the zoom lens group
2607 movement. A negative value moves the zoom lens group towards the
2608 wide-angle direction. The zoom speed unit is driver-specific.
2610 ``V4L2_CID_IRIS_ABSOLUTE (integer)``
2611 This control sets the camera's aperture to the specified value. The
2612 unit is undefined. Larger values open the iris wider, smaller values
2615 ``V4L2_CID_IRIS_RELATIVE (integer)``
2616 This control modifies the camera's aperture by the specified amount.
2617 The unit is undefined. Positive values open the iris one step
2618 further, negative values close it one step further. This is a
2621 ``V4L2_CID_PRIVACY (boolean)``
2622 Prevent video from being acquired by the camera. When this control
2623 is set to ``TRUE`` (1), no image can be captured by the camera.
2624 Common means to enforce privacy are mechanical obturation of the
2625 sensor and firmware image processing, but the device is not
2626 restricted to these methods. Devices that implement the privacy
2627 control must support read access and may support write access.
2629 ``V4L2_CID_BAND_STOP_FILTER (integer)``
2630 Switch the band-stop filter of a camera sensor on or off, or specify
2631 its strength. Such band-stop filters can be used, for example, to
2632 filter out the fluorescent light component.
2634 .. _v4l2-auto-n-preset-white-balance:
2636 ``V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE``
2639 enum v4l2_auto_n_preset_white_balance -
2640 Sets white balance to automatic, manual or a preset. The presets
2641 determine color temperature of the light as a hint to the camera for
2642 white balance adjustments resulting in most accurate color
2643 representation. The following white balance presets are listed in
2644 order of increasing color temperature.
2646 .. tabularcolumns:: |p{7.0 cm}|p{10.5cm}|
2652 * - ``V4L2_WHITE_BALANCE_MANUAL``
2653 - Manual white balance.
2654 * - ``V4L2_WHITE_BALANCE_AUTO``
2655 - Automatic white balance adjustments.
2656 * - ``V4L2_WHITE_BALANCE_INCANDESCENT``
2657 - White balance setting for incandescent (tungsten) lighting. It
2658 generally cools down the colors and corresponds approximately to
2659 2500...3500 K color temperature range.
2660 * - ``V4L2_WHITE_BALANCE_FLUORESCENT``
2661 - White balance preset for fluorescent lighting. It corresponds
2662 approximately to 4000...5000 K color temperature.
2663 * - ``V4L2_WHITE_BALANCE_FLUORESCENT_H``
2664 - With this setting the camera will compensate for fluorescent H
2666 * - ``V4L2_WHITE_BALANCE_HORIZON``
2667 - White balance setting for horizon daylight. It corresponds
2668 approximately to 5000 K color temperature.
2669 * - ``V4L2_WHITE_BALANCE_DAYLIGHT``
2670 - White balance preset for daylight (with clear sky). It corresponds
2671 approximately to 5000...6500 K color temperature.
2672 * - ``V4L2_WHITE_BALANCE_FLASH``
2673 - With this setting the camera will compensate for the flash light.
2674 It slightly warms up the colors and corresponds roughly to
2675 5000...5500 K color temperature.
2676 * - ``V4L2_WHITE_BALANCE_CLOUDY``
2677 - White balance preset for moderately overcast sky. This option
2678 corresponds approximately to 6500...8000 K color temperature
2680 * - ``V4L2_WHITE_BALANCE_SHADE``
2681 - White balance preset for shade or heavily overcast sky. It
2682 corresponds approximately to 9000...10000 K color temperature.
2686 .. _v4l2-wide-dynamic-range:
2688 ``V4L2_CID_WIDE_DYNAMIC_RANGE (boolean)``
2689 Enables or disables the camera's wide dynamic range feature. This
2690 feature allows to obtain clear images in situations where intensity
2691 of the illumination varies significantly throughout the scene, i.e.
2692 there are simultaneously very dark and very bright areas. It is most
2693 commonly realized in cameras by combining two subsequent frames with
2694 different exposure times. [#f1]_
2696 .. _v4l2-image-stabilization:
2698 ``V4L2_CID_IMAGE_STABILIZATION (boolean)``
2699 Enables or disables image stabilization.
2701 ``V4L2_CID_ISO_SENSITIVITY (integer menu)``
2702 Determines ISO equivalent of an image sensor indicating the sensor's
2703 sensitivity to light. The numbers are expressed in arithmetic scale,
2704 as per :ref:`iso12232` standard, where doubling the sensor
2705 sensitivity is represented by doubling the numerical ISO value.
2706 Applications should interpret the values as standard ISO values
2707 multiplied by 1000, e.g. control value 800 stands for ISO 0.8.
2708 Drivers will usually support only a subset of standard ISO values.
2709 The effect of setting this control while the
2710 ``V4L2_CID_ISO_SENSITIVITY_AUTO`` control is set to a value other
2711 than ``V4L2_CID_ISO_SENSITIVITY_MANUAL`` is undefined, drivers
2712 should ignore such requests.
2714 .. _v4l2-iso-sensitivity-auto-type:
2716 ``V4L2_CID_ISO_SENSITIVITY_AUTO``
2719 enum v4l2_iso_sensitivity_type -
2720 Enables or disables automatic ISO sensitivity adjustments.
2728 * - ``V4L2_CID_ISO_SENSITIVITY_MANUAL``
2729 - Manual ISO sensitivity.
2730 * - ``V4L2_CID_ISO_SENSITIVITY_AUTO``
2731 - Automatic ISO sensitivity adjustments.
2735 .. _v4l2-scene-mode:
2737 ``V4L2_CID_SCENE_MODE``
2740 enum v4l2_scene_mode -
2741 This control allows to select scene programs as the camera automatic
2742 modes optimized for common shooting scenes. Within these modes the
2743 camera determines best exposure, aperture, focusing, light metering,
2744 white balance and equivalent sensitivity. The controls of those
2745 parameters are influenced by the scene mode control. An exact
2746 behavior in each mode is subject to the camera specification.
2748 When the scene mode feature is not used, this control should be set
2749 to ``V4L2_SCENE_MODE_NONE`` to make sure the other possibly related
2750 controls are accessible. The following scene programs are defined:
2752 .. tabularcolumns:: |p{6.0cm}|p{11.5cm}|
2758 * - ``V4L2_SCENE_MODE_NONE``
2759 - The scene mode feature is disabled.
2760 * - ``V4L2_SCENE_MODE_BACKLIGHT``
2761 - Backlight. Compensates for dark shadows when light is coming from
2762 behind a subject, also by automatically turning on the flash.
2763 * - ``V4L2_SCENE_MODE_BEACH_SNOW``
2764 - Beach and snow. This mode compensates for all-white or bright
2765 scenes, which tend to look gray and low contrast, when camera's
2766 automatic exposure is based on an average scene brightness. To
2767 compensate, this mode automatically slightly overexposes the
2768 frames. The white balance may also be adjusted to compensate for
2769 the fact that reflected snow looks bluish rather than white.
2770 * - ``V4L2_SCENE_MODE_CANDLELIGHT``
2771 - Candle light. The camera generally raises the ISO sensitivity and
2772 lowers the shutter speed. This mode compensates for relatively
2773 close subject in the scene. The flash is disabled in order to
2774 preserve the ambiance of the light.
2775 * - ``V4L2_SCENE_MODE_DAWN_DUSK``
2776 - Dawn and dusk. Preserves the colors seen in low natural light
2777 before dusk and after down. The camera may turn off the flash, and
2778 automatically focus at infinity. It will usually boost saturation
2779 and lower the shutter speed.
2780 * - ``V4L2_SCENE_MODE_FALL_COLORS``
2781 - Fall colors. Increases saturation and adjusts white balance for
2782 color enhancement. Pictures of autumn leaves get saturated reds
2784 * - ``V4L2_SCENE_MODE_FIREWORKS``
2785 - Fireworks. Long exposure times are used to capture the expanding
2786 burst of light from a firework. The camera may invoke image
2788 * - ``V4L2_SCENE_MODE_LANDSCAPE``
2789 - Landscape. The camera may choose a small aperture to provide deep
2790 depth of field and long exposure duration to help capture detail
2791 in dim light conditions. The focus is fixed at infinity. Suitable
2792 for distant and wide scenery.
2793 * - ``V4L2_SCENE_MODE_NIGHT``
2794 - Night, also known as Night Landscape. Designed for low light
2795 conditions, it preserves detail in the dark areas without blowing
2796 out bright objects. The camera generally sets itself to a
2797 medium-to-high ISO sensitivity, with a relatively long exposure
2798 time, and turns flash off. As such, there will be increased image
2799 noise and the possibility of blurred image.
2800 * - ``V4L2_SCENE_MODE_PARTY_INDOOR``
2801 - Party and indoor. Designed to capture indoor scenes that are lit
2802 by indoor background lighting as well as the flash. The camera
2803 usually increases ISO sensitivity, and adjusts exposure for the
2804 low light conditions.
2805 * - ``V4L2_SCENE_MODE_PORTRAIT``
2806 - Portrait. The camera adjusts the aperture so that the depth of
2807 field is reduced, which helps to isolate the subject against a
2808 smooth background. Most cameras recognize the presence of faces in
2809 the scene and focus on them. The color hue is adjusted to enhance
2810 skin tones. The intensity of the flash is often reduced.
2811 * - ``V4L2_SCENE_MODE_SPORTS``
2812 - Sports. Significantly increases ISO and uses a fast shutter speed
2813 to freeze motion of rapidly-moving subjects. Increased image noise
2814 may be seen in this mode.
2815 * - ``V4L2_SCENE_MODE_SUNSET``
2816 - Sunset. Preserves deep hues seen in sunsets and sunrises. It bumps
2818 * - ``V4L2_SCENE_MODE_TEXT``
2819 - Text. It applies extra contrast and sharpness, it is typically a
2820 black-and-white mode optimized for readability. Automatic focus
2821 may be switched to close-up mode and this setting may also involve
2822 some lens-distortion correction.
2826 ``V4L2_CID_3A_LOCK (bitmask)``
2827 This control locks or unlocks the automatic focus, exposure and
2828 white balance. The automatic adjustments can be paused independently
2829 by setting the corresponding lock bit to 1. The camera then retains
2830 the settings until the lock bit is cleared. The following lock bits
2833 When a given algorithm is not enabled, drivers should ignore
2834 requests to lock it and should return no error. An example might be
2835 an application setting bit ``V4L2_LOCK_WHITE_BALANCE`` when the
2836 ``V4L2_CID_AUTO_WHITE_BALANCE`` control is set to ``FALSE``. The
2837 value of this control may be changed by exposure, white balance or
2846 * - ``V4L2_LOCK_EXPOSURE``
2847 - Automatic exposure adjustments lock.
2848 * - ``V4L2_LOCK_WHITE_BALANCE``
2849 - Automatic white balance adjustments lock.
2850 * - ``V4L2_LOCK_FOCUS``
2851 - Automatic focus lock.
2855 ``V4L2_CID_PAN_SPEED (integer)``
2856 This control turns the camera horizontally at the specific speed.
2857 The unit is undefined. A positive value moves the camera to the
2858 right (clockwise when viewed from above), a negative value to the
2859 left. A value of zero stops the motion if one is in progress and has
2860 no effect otherwise.
2862 ``V4L2_CID_TILT_SPEED (integer)``
2863 This control turns the camera vertically at the specified speed. The
2864 unit is undefined. A positive value moves the camera up, a negative
2865 value down. A value of zero stops the motion if one is in progress
2866 and has no effect otherwise.
2871 FM Transmitter Control Reference
2872 ================================
2874 The FM Transmitter (FM_TX) class includes controls for common features
2875 of FM transmissions capable devices. Currently this class includes
2876 parameters for audio compression, pilot tone generation, audio deviation
2877 limiter, RDS transmission and tuning power features.
2880 .. _fm-tx-control-id:
2885 ``V4L2_CID_FM_TX_CLASS (class)``
2886 The FM_TX class descriptor. Calling
2887 :ref:`VIDIOC_QUERYCTRL` for this control will
2888 return a description of this control class.
2890 ``V4L2_CID_RDS_TX_DEVIATION (integer)``
2891 Configures RDS signal frequency deviation level in Hz. The range and
2892 step are driver-specific.
2894 ``V4L2_CID_RDS_TX_PI (integer)``
2895 Sets the RDS Programme Identification field for transmission.
2897 ``V4L2_CID_RDS_TX_PTY (integer)``
2898 Sets the RDS Programme Type field for transmission. This encodes up
2899 to 31 pre-defined programme types.
2901 ``V4L2_CID_RDS_TX_PS_NAME (string)``
2902 Sets the Programme Service name (PS_NAME) for transmission. It is
2903 intended for static display on a receiver. It is the primary aid to
2904 listeners in programme service identification and selection. In
2905 Annex E of :ref:`iec62106`, the RDS specification, there is a full
2906 description of the correct character encoding for Programme Service
2907 name strings. Also from RDS specification, PS is usually a single
2908 eight character text. However, it is also possible to find receivers
2909 which can scroll strings sized as 8 x N characters. So, this control
2910 must be configured with steps of 8 characters. The result is it must
2911 always contain a string with size multiple of 8.
2913 ``V4L2_CID_RDS_TX_RADIO_TEXT (string)``
2914 Sets the Radio Text info for transmission. It is a textual
2915 description of what is being broadcasted. RDS Radio Text can be
2916 applied when broadcaster wishes to transmit longer PS names,
2917 programme-related information or any other text. In these cases,
2918 RadioText should be used in addition to ``V4L2_CID_RDS_TX_PS_NAME``.
2919 The encoding for Radio Text strings is also fully described in Annex
2920 E of :ref:`iec62106`. The length of Radio Text strings depends on
2921 which RDS Block is being used to transmit it, either 32 (2A block)
2922 or 64 (2B block). However, it is also possible to find receivers
2923 which can scroll strings sized as 32 x N or 64 x N characters. So,
2924 this control must be configured with steps of 32 or 64 characters.
2925 The result is it must always contain a string with size multiple of
2928 ``V4L2_CID_RDS_TX_MONO_STEREO (boolean)``
2929 Sets the Mono/Stereo bit of the Decoder Identification code. If set,
2930 then the audio was recorded as stereo.
2932 ``V4L2_CID_RDS_TX_ARTIFICIAL_HEAD (boolean)``
2934 `Artificial Head <http://en.wikipedia.org/wiki/Artificial_head>`__
2935 bit of the Decoder Identification code. If set, then the audio was
2936 recorded using an artificial head.
2938 ``V4L2_CID_RDS_TX_COMPRESSED (boolean)``
2939 Sets the Compressed bit of the Decoder Identification code. If set,
2940 then the audio is compressed.
2942 ``V4L2_CID_RDS_TX_DYNAMIC_PTY (boolean)``
2943 Sets the Dynamic PTY bit of the Decoder Identification code. If set,
2944 then the PTY code is dynamically switched.
2946 ``V4L2_CID_RDS_TX_TRAFFIC_ANNOUNCEMENT (boolean)``
2947 If set, then a traffic announcement is in progress.
2949 ``V4L2_CID_RDS_TX_TRAFFIC_PROGRAM (boolean)``
2950 If set, then the tuned programme carries traffic announcements.
2952 ``V4L2_CID_RDS_TX_MUSIC_SPEECH (boolean)``
2953 If set, then this channel broadcasts music. If cleared, then it
2954 broadcasts speech. If the transmitter doesn't make this distinction,
2955 then it should be set.
2957 ``V4L2_CID_RDS_TX_ALT_FREQS_ENABLE (boolean)``
2958 If set, then transmit alternate frequencies.
2960 ``V4L2_CID_RDS_TX_ALT_FREQS (__u32 array)``
2961 The alternate frequencies in kHz units. The RDS standard allows for
2962 up to 25 frequencies to be defined. Drivers may support fewer
2963 frequencies so check the array size.
2965 ``V4L2_CID_AUDIO_LIMITER_ENABLED (boolean)``
2966 Enables or disables the audio deviation limiter feature. The limiter
2967 is useful when trying to maximize the audio volume, minimize
2968 receiver-generated distortion and prevent overmodulation.
2970 ``V4L2_CID_AUDIO_LIMITER_RELEASE_TIME (integer)``
2971 Sets the audio deviation limiter feature release time. Unit is in
2972 useconds. Step and range are driver-specific.
2974 ``V4L2_CID_AUDIO_LIMITER_DEVIATION (integer)``
2975 Configures audio frequency deviation level in Hz. The range and step
2976 are driver-specific.
2978 ``V4L2_CID_AUDIO_COMPRESSION_ENABLED (boolean)``
2979 Enables or disables the audio compression feature. This feature
2980 amplifies signals below the threshold by a fixed gain and compresses
2981 audio signals above the threshold by the ratio of Threshold/(Gain +
2984 ``V4L2_CID_AUDIO_COMPRESSION_GAIN (integer)``
2985 Sets the gain for audio compression feature. It is a dB value. The
2986 range and step are driver-specific.
2988 ``V4L2_CID_AUDIO_COMPRESSION_THRESHOLD (integer)``
2989 Sets the threshold level for audio compression freature. It is a dB
2990 value. The range and step are driver-specific.
2992 ``V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME (integer)``
2993 Sets the attack time for audio compression feature. It is a useconds
2994 value. The range and step are driver-specific.
2996 ``V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME (integer)``
2997 Sets the release time for audio compression feature. It is a
2998 useconds value. The range and step are driver-specific.
3000 ``V4L2_CID_PILOT_TONE_ENABLED (boolean)``
3001 Enables or disables the pilot tone generation feature.
3003 ``V4L2_CID_PILOT_TONE_DEVIATION (integer)``
3004 Configures pilot tone frequency deviation level. Unit is in Hz. The
3005 range and step are driver-specific.
3007 ``V4L2_CID_PILOT_TONE_FREQUENCY (integer)``
3008 Configures pilot tone frequency value. Unit is in Hz. The range and
3009 step are driver-specific.
3011 ``V4L2_CID_TUNE_PREEMPHASIS``
3014 enum v4l2_preemphasis -
3015 Configures the pre-emphasis value for broadcasting. A pre-emphasis
3016 filter is applied to the broadcast to accentuate the high audio
3017 frequencies. Depending on the region, a time constant of either 50
3018 or 75 useconds is used. The enum v4l2_preemphasis defines possible
3019 values for pre-emphasis. Here they are:
3027 * - ``V4L2_PREEMPHASIS_DISABLED``
3028 - No pre-emphasis is applied.
3029 * - ``V4L2_PREEMPHASIS_50_uS``
3030 - A pre-emphasis of 50 uS is used.
3031 * - ``V4L2_PREEMPHASIS_75_uS``
3032 - A pre-emphasis of 75 uS is used.
3036 ``V4L2_CID_TUNE_POWER_LEVEL (integer)``
3037 Sets the output power level for signal transmission. Unit is in
3038 dBuV. Range and step are driver-specific.
3040 ``V4L2_CID_TUNE_ANTENNA_CAPACITOR (integer)``
3041 This selects the value of antenna tuning capacitor manually or
3042 automatically if set to zero. Unit, range and step are
3045 For more details about RDS specification, refer to :ref:`iec62106`
3046 document, from CENELEC.
3051 Flash Control Reference
3052 =======================
3054 The V4L2 flash controls are intended to provide generic access to flash
3055 controller devices. Flash controller devices are typically used in
3058 The interface can support both LED and xenon flash devices. As of
3059 writing this, there is no xenon flash driver using this interface.
3062 .. _flash-controls-use-cases:
3068 Unsynchronised LED flash (software strobe)
3069 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
3071 Unsynchronised LED flash is controlled directly by the host as the
3072 sensor. The flash must be enabled by the host before the exposure of the
3073 image starts and disabled once it ends. The host is fully responsible
3074 for the timing of the flash.
3076 Example of such device: Nokia N900.
3079 Synchronised LED flash (hardware strobe)
3080 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
3082 The synchronised LED flash is pre-programmed by the host (power and
3083 timeout) but controlled by the sensor through a strobe signal from the
3084 sensor to the flash.
3086 The sensor controls the flash duration and timing. This information
3087 typically must be made available to the sensor.
3093 LED flash may be used as torch in conjunction with another use case
3094 involving camera or individually.
3097 .. _flash-control-id:
3102 ``V4L2_CID_FLASH_CLASS (class)``
3103 The FLASH class descriptor.
3105 ``V4L2_CID_FLASH_LED_MODE (menu)``
3106 Defines the mode of the flash LED, the high-power white LED attached
3107 to the flash controller. Setting this control may not be possible in
3108 presence of some faults. See V4L2_CID_FLASH_FAULT.
3116 * - ``V4L2_FLASH_LED_MODE_NONE``
3118 * - ``V4L2_FLASH_LED_MODE_FLASH``
3120 * - ``V4L2_FLASH_LED_MODE_TORCH``
3121 - Torch mode. See V4L2_CID_FLASH_TORCH_INTENSITY.
3125 ``V4L2_CID_FLASH_STROBE_SOURCE (menu)``
3126 Defines the source of the flash LED strobe.
3128 .. tabularcolumns:: |p{7.0cm}|p{10.5cm}|
3134 * - ``V4L2_FLASH_STROBE_SOURCE_SOFTWARE``
3135 - The flash strobe is triggered by using the
3136 V4L2_CID_FLASH_STROBE control.
3137 * - ``V4L2_FLASH_STROBE_SOURCE_EXTERNAL``
3138 - The flash strobe is triggered by an external source. Typically
3139 this is a sensor, which makes it possible to synchronises the
3140 flash strobe start to exposure start.
3144 ``V4L2_CID_FLASH_STROBE (button)``
3145 Strobe flash. Valid when V4L2_CID_FLASH_LED_MODE is set to
3146 V4L2_FLASH_LED_MODE_FLASH and V4L2_CID_FLASH_STROBE_SOURCE
3147 is set to V4L2_FLASH_STROBE_SOURCE_SOFTWARE. Setting this
3148 control may not be possible in presence of some faults. See
3149 V4L2_CID_FLASH_FAULT.
3151 ``V4L2_CID_FLASH_STROBE_STOP (button)``
3152 Stop flash strobe immediately.
3154 ``V4L2_CID_FLASH_STROBE_STATUS (boolean)``
3155 Strobe status: whether the flash is strobing at the moment or not.
3156 This is a read-only control.
3158 ``V4L2_CID_FLASH_TIMEOUT (integer)``
3159 Hardware timeout for flash. The flash strobe is stopped after this
3160 period of time has passed from the start of the strobe.
3162 ``V4L2_CID_FLASH_INTENSITY (integer)``
3163 Intensity of the flash strobe when the flash LED is in flash mode
3164 (V4L2_FLASH_LED_MODE_FLASH). The unit should be milliamps (mA)
3167 ``V4L2_CID_FLASH_TORCH_INTENSITY (integer)``
3168 Intensity of the flash LED in torch mode
3169 (V4L2_FLASH_LED_MODE_TORCH). The unit should be milliamps (mA)
3170 if possible. Setting this control may not be possible in presence of
3171 some faults. See V4L2_CID_FLASH_FAULT.
3173 ``V4L2_CID_FLASH_INDICATOR_INTENSITY (integer)``
3174 Intensity of the indicator LED. The indicator LED may be fully
3175 independent of the flash LED. The unit should be microamps (uA) if
3178 ``V4L2_CID_FLASH_FAULT (bitmask)``
3179 Faults related to the flash. The faults tell about specific problems
3180 in the flash chip itself or the LEDs attached to it. Faults may
3181 prevent further use of some of the flash controls. In particular,
3182 V4L2_CID_FLASH_LED_MODE is set to V4L2_FLASH_LED_MODE_NONE
3183 if the fault affects the flash LED. Exactly which faults have such
3184 an effect is chip dependent. Reading the faults resets the control
3185 and returns the chip to a usable state if possible.
3187 .. tabularcolumns:: |p{8.0cm}|p{9.5cm}|
3193 * - ``V4L2_FLASH_FAULT_OVER_VOLTAGE``
3194 - Flash controller voltage to the flash LED has exceeded the limit
3195 specific to the flash controller.
3196 * - ``V4L2_FLASH_FAULT_TIMEOUT``
3197 - The flash strobe was still on when the timeout set by the user ---
3198 V4L2_CID_FLASH_TIMEOUT control --- has expired. Not all flash
3199 controllers may set this in all such conditions.
3200 * - ``V4L2_FLASH_FAULT_OVER_TEMPERATURE``
3201 - The flash controller has overheated.
3202 * - ``V4L2_FLASH_FAULT_SHORT_CIRCUIT``
3203 - The short circuit protection of the flash controller has been
3205 * - ``V4L2_FLASH_FAULT_OVER_CURRENT``
3206 - Current in the LED power supply has exceeded the limit specific to
3207 the flash controller.
3208 * - ``V4L2_FLASH_FAULT_INDICATOR``
3209 - The flash controller has detected a short or open circuit
3210 condition on the indicator LED.
3211 * - ``V4L2_FLASH_FAULT_UNDER_VOLTAGE``
3212 - Flash controller voltage to the flash LED has been below the
3213 minimum limit specific to the flash controller.
3214 * - ``V4L2_FLASH_FAULT_INPUT_VOLTAGE``
3215 - The input voltage of the flash controller is below the limit under
3216 which strobing the flash at full current will not be possible.The
3217 condition persists until this flag is no longer set.
3218 * - ``V4L2_FLASH_FAULT_LED_OVER_TEMPERATURE``
3219 - The temperature of the LED has exceeded its allowed upper limit.
3223 ``V4L2_CID_FLASH_CHARGE (boolean)``
3224 Enable or disable charging of the xenon flash capacitor.
3226 ``V4L2_CID_FLASH_READY (boolean)``
3227 Is the flash ready to strobe? Xenon flashes require their capacitors
3228 charged before strobing. LED flashes often require a cooldown period
3229 after strobe during which another strobe will not be possible. This
3230 is a read-only control.
3235 JPEG Control Reference
3236 ======================
3238 The JPEG class includes controls for common features of JPEG encoders
3239 and decoders. Currently it includes features for codecs implementing
3240 progressive baseline DCT compression process with Huffman entrophy
3244 .. _jpeg-control-id:
3249 ``V4L2_CID_JPEG_CLASS (class)``
3250 The JPEG class descriptor. Calling
3251 :ref:`VIDIOC_QUERYCTRL` for this control will
3252 return a description of this control class.
3254 ``V4L2_CID_JPEG_CHROMA_SUBSAMPLING (menu)``
3255 The chroma subsampling factors describe how each component of an
3256 input image is sampled, in respect to maximum sample rate in each
3257 spatial dimension. See :ref:`itu-t81`, clause A.1.1. for more
3258 details. The ``V4L2_CID_JPEG_CHROMA_SUBSAMPLING`` control determines
3259 how Cb and Cr components are downsampled after converting an input
3260 image from RGB to Y'CbCr color space.
3262 .. tabularcolumns:: |p{7.0cm}|p{10.5cm}|
3268 * - ``V4L2_JPEG_CHROMA_SUBSAMPLING_444``
3269 - No chroma subsampling, each pixel has Y, Cr and Cb values.
3270 * - ``V4L2_JPEG_CHROMA_SUBSAMPLING_422``
3271 - Horizontally subsample Cr, Cb components by a factor of 2.
3272 * - ``V4L2_JPEG_CHROMA_SUBSAMPLING_420``
3273 - Subsample Cr, Cb components horizontally and vertically by 2.
3274 * - ``V4L2_JPEG_CHROMA_SUBSAMPLING_411``
3275 - Horizontally subsample Cr, Cb components by a factor of 4.
3276 * - ``V4L2_JPEG_CHROMA_SUBSAMPLING_410``
3277 - Subsample Cr, Cb components horizontally by 4 and vertically by 2.
3278 * - ``V4L2_JPEG_CHROMA_SUBSAMPLING_GRAY``
3279 - Use only luminance component.
3283 ``V4L2_CID_JPEG_RESTART_INTERVAL (integer)``
3284 The restart interval determines an interval of inserting RSTm
3285 markers (m = 0..7). The purpose of these markers is to additionally
3286 reinitialize the encoder process, in order to process blocks of an
3287 image independently. For the lossy compression processes the restart
3288 interval unit is MCU (Minimum Coded Unit) and its value is contained
3289 in DRI (Define Restart Interval) marker. If
3290 ``V4L2_CID_JPEG_RESTART_INTERVAL`` control is set to 0, DRI and RSTm
3291 markers will not be inserted.
3293 .. _jpeg-quality-control:
3295 ``V4L2_CID_JPEG_COMPRESSION_QUALITY (integer)``
3296 ``V4L2_CID_JPEG_COMPRESSION_QUALITY`` control determines trade-off
3297 between image quality and size. It provides simpler method for
3298 applications to control image quality, without a need for direct
3299 reconfiguration of luminance and chrominance quantization tables. In
3300 cases where a driver uses quantization tables configured directly by
3301 an application, using interfaces defined elsewhere,
3302 ``V4L2_CID_JPEG_COMPRESSION_QUALITY`` control should be set by
3305 The value range of this control is driver-specific. Only positive,
3306 non-zero values are meaningful. The recommended range is 1 - 100,
3307 where larger values correspond to better image quality.
3309 .. _jpeg-active-marker-control:
3311 ``V4L2_CID_JPEG_ACTIVE_MARKER (bitmask)``
3312 Specify which JPEG markers are included in compressed stream. This
3313 control is valid only for encoders.
3321 * - ``V4L2_JPEG_ACTIVE_MARKER_APP0``
3322 - Application data segment APP\ :sub:`0`.
3323 * - ``V4L2_JPEG_ACTIVE_MARKER_APP1``
3324 - Application data segment APP\ :sub:`1`.
3325 * - ``V4L2_JPEG_ACTIVE_MARKER_COM``
3327 * - ``V4L2_JPEG_ACTIVE_MARKER_DQT``
3328 - Quantization tables segment.
3329 * - ``V4L2_JPEG_ACTIVE_MARKER_DHT``
3330 - Huffman tables segment.
3334 For more details about JPEG specification, refer to :ref:`itu-t81`,
3335 :ref:`jfif`, :ref:`w3c-jpeg-jfif`.
3338 .. _image-source-controls:
3340 Image Source Control Reference
3341 ==============================
3343 The Image Source control class is intended for low-level control of
3344 image source devices such as image sensors. The devices feature an
3345 analogue to digital converter and a bus transmitter to transmit the
3346 image data out of the device.
3349 .. _image-source-control-id:
3351 Image Source Control IDs
3352 ------------------------
3354 ``V4L2_CID_IMAGE_SOURCE_CLASS (class)``
3355 The IMAGE_SOURCE class descriptor.
3357 ``V4L2_CID_VBLANK (integer)``
3358 Vertical blanking. The idle period after every frame during which no
3359 image data is produced. The unit of vertical blanking is a line.
3360 Every line has length of the image width plus horizontal blanking at
3361 the pixel rate defined by ``V4L2_CID_PIXEL_RATE`` control in the
3364 ``V4L2_CID_HBLANK (integer)``
3365 Horizontal blanking. The idle period after every line of image data
3366 during which no image data is produced. The unit of horizontal
3369 ``V4L2_CID_ANALOGUE_GAIN (integer)``
3370 Analogue gain is gain affecting all colour components in the pixel
3371 matrix. The gain operation is performed in the analogue domain
3372 before A/D conversion.
3374 ``V4L2_CID_TEST_PATTERN_RED (integer)``
3375 Test pattern red colour component.
3377 ``V4L2_CID_TEST_PATTERN_GREENR (integer)``
3378 Test pattern green (next to red) colour component.
3380 ``V4L2_CID_TEST_PATTERN_BLUE (integer)``
3381 Test pattern blue colour component.
3383 ``V4L2_CID_TEST_PATTERN_GREENB (integer)``
3384 Test pattern green (next to blue) colour component.
3387 .. _image-process-controls:
3389 Image Process Control Reference
3390 ===============================
3392 The Image Process control class is intended for low-level control of
3393 image processing functions. Unlike ``V4L2_CID_IMAGE_SOURCE_CLASS``, the
3394 controls in this class affect processing the image, and do not control
3398 .. _image-process-control-id:
3400 Image Process Control IDs
3401 -------------------------
3403 ``V4L2_CID_IMAGE_PROC_CLASS (class)``
3404 The IMAGE_PROC class descriptor.
3406 ``V4L2_CID_LINK_FREQ (integer menu)``
3407 Data bus frequency. Together with the media bus pixel code, bus type
3408 (clock cycles per sample), the data bus frequency defines the pixel
3409 rate (``V4L2_CID_PIXEL_RATE``) in the pixel array (or possibly
3410 elsewhere, if the device is not an image sensor). The frame rate can
3411 be calculated from the pixel clock, image width and height and
3412 horizontal and vertical blanking. While the pixel rate control may
3413 be defined elsewhere than in the subdev containing the pixel array,
3414 the frame rate cannot be obtained from that information. This is
3415 because only on the pixel array it can be assumed that the vertical
3416 and horizontal blanking information is exact: no other blanking is
3417 allowed in the pixel array. The selection of frame rate is performed
3418 by selecting the desired horizontal and vertical blanking. The unit
3419 of this control is Hz.
3421 ``V4L2_CID_PIXEL_RATE (64-bit integer)``
3422 Pixel rate in the source pads of the subdev. This control is
3423 read-only and its unit is pixels / second.
3425 ``V4L2_CID_TEST_PATTERN (menu)``
3426 Some capture/display/sensor devices have the capability to generate
3427 test pattern images. These hardware specific test patterns can be
3428 used to test if a device is working properly.
3430 ``V4L2_CID_DEINTERLACING_MODE (menu)``
3431 The video deinterlacing mode (such as Bob, Weave, ...). The menu items are
3432 driver specific and are documented in :ref:`v4l-drivers`.
3434 ``V4L2_CID_DIGITAL_GAIN (integer)``
3435 Digital gain is the value by which all colour components
3436 are multiplied by. Typically the digital gain applied is the
3437 control value divided by e.g. 0x100, meaning that to get no
3438 digital gain the control value needs to be 0x100. The no-gain
3439 configuration is also typically the default.
3444 Digital Video Control Reference
3445 ===============================
3447 The Digital Video control class is intended to control receivers and
3448 transmitters for `VGA <http://en.wikipedia.org/wiki/Vga>`__,
3449 `DVI <http://en.wikipedia.org/wiki/Digital_Visual_Interface>`__
3450 (Digital Visual Interface), HDMI (:ref:`hdmi`) and DisplayPort
3451 (:ref:`dp`). These controls are generally expected to be private to
3452 the receiver or transmitter subdevice that implements them, so they are
3453 only exposed on the ``/dev/v4l-subdev*`` device node.
3457 Note that these devices can have multiple input or output pads which are
3458 hooked up to e.g. HDMI connectors. Even though the subdevice will
3459 receive or transmit video from/to only one of those pads, the other pads
3460 can still be active when it comes to EDID (Extended Display
3461 Identification Data, :ref:`vesaedid`) and HDCP (High-bandwidth Digital
3462 Content Protection System, :ref:`hdcp`) processing, allowing the
3463 device to do the fairly slow EDID/HDCP handling in advance. This allows
3464 for quick switching between connectors.
3466 These pads appear in several of the controls in this section as
3467 bitmasks, one bit for each pad. Bit 0 corresponds to pad 0, bit 1 to pad
3468 1, etc. The maximum value of the control is the set of valid pads.
3473 Digital Video Control IDs
3474 -------------------------
3476 ``V4L2_CID_DV_CLASS (class)``
3477 The Digital Video class descriptor.
3479 ``V4L2_CID_DV_TX_HOTPLUG (bitmask)``
3480 Many connectors have a hotplug pin which is high if EDID information
3481 is available from the source. This control shows the state of the
3482 hotplug pin as seen by the transmitter. Each bit corresponds to an
3483 output pad on the transmitter. If an output pad does not have an
3484 associated hotplug pin, then the bit for that pad will be 0. This
3485 read-only control is applicable to DVI-D, HDMI and DisplayPort
3488 ``V4L2_CID_DV_TX_RXSENSE (bitmask)``
3489 Rx Sense is the detection of pull-ups on the TMDS clock lines. This
3490 normally means that the sink has left/entered standby (i.e. the
3491 transmitter can sense that the receiver is ready to receive video).
3492 Each bit corresponds to an output pad on the transmitter. If an
3493 output pad does not have an associated Rx Sense, then the bit for
3494 that pad will be 0. This read-only control is applicable to DVI-D
3497 ``V4L2_CID_DV_TX_EDID_PRESENT (bitmask)``
3498 When the transmitter sees the hotplug signal from the receiver it
3499 will attempt to read the EDID. If set, then the transmitter has read
3500 at least the first block (= 128 bytes). Each bit corresponds to an
3501 output pad on the transmitter. If an output pad does not support
3502 EDIDs, then the bit for that pad will be 0. This read-only control
3503 is applicable to VGA, DVI-A/D, HDMI and DisplayPort connectors.
3505 ``V4L2_CID_DV_TX_MODE``
3508 enum v4l2_dv_tx_mode -
3509 HDMI transmitters can transmit in DVI-D mode (just video) or in HDMI
3510 mode (video + audio + auxiliary data). This control selects which
3511 mode to use: V4L2_DV_TX_MODE_DVI_D or V4L2_DV_TX_MODE_HDMI.
3512 This control is applicable to HDMI connectors.
3514 ``V4L2_CID_DV_TX_RGB_RANGE``
3517 enum v4l2_dv_rgb_range -
3518 Select the quantization range for RGB output. V4L2_DV_RANGE_AUTO
3519 follows the RGB quantization range specified in the standard for the
3520 video interface (ie. :ref:`cea861` for HDMI).
3521 V4L2_DV_RANGE_LIMITED and V4L2_DV_RANGE_FULL override the
3522 standard to be compatible with sinks that have not implemented the
3523 standard correctly (unfortunately quite common for HDMI and DVI-D).
3524 Full range allows all possible values to be used whereas limited
3525 range sets the range to (16 << (N-8)) - (235 << (N-8)) where N is
3526 the number of bits per component. This control is applicable to VGA,
3527 DVI-A/D, HDMI and DisplayPort connectors.
3529 ``V4L2_CID_DV_TX_IT_CONTENT_TYPE``
3532 enum v4l2_dv_it_content_type -
3533 Configures the IT Content Type of the transmitted video. This
3534 information is sent over HDMI and DisplayPort connectors as part of
3535 the AVI InfoFrame. The term 'IT Content' is used for content that
3536 originates from a computer as opposed to content from a TV broadcast
3537 or an analog source. The enum v4l2_dv_it_content_type defines
3538 the possible content types:
3540 .. tabularcolumns:: |p{7.0cm}|p{10.5cm}|
3546 * - ``V4L2_DV_IT_CONTENT_TYPE_GRAPHICS``
3547 - Graphics content. Pixel data should be passed unfiltered and
3548 without analog reconstruction.
3549 * - ``V4L2_DV_IT_CONTENT_TYPE_PHOTO``
3550 - Photo content. The content is derived from digital still pictures.
3551 The content should be passed through with minimal scaling and
3552 picture enhancements.
3553 * - ``V4L2_DV_IT_CONTENT_TYPE_CINEMA``
3555 * - ``V4L2_DV_IT_CONTENT_TYPE_GAME``
3556 - Game content. Audio and video latency should be minimized.
3557 * - ``V4L2_DV_IT_CONTENT_TYPE_NO_ITC``
3558 - No IT Content information is available and the ITC bit in the AVI
3559 InfoFrame is set to 0.
3563 ``V4L2_CID_DV_RX_POWER_PRESENT (bitmask)``
3564 Detects whether the receiver receives power from the source (e.g.
3565 HDMI carries 5V on one of the pins). This is often used to power an
3566 eeprom which contains EDID information, such that the source can
3567 read the EDID even if the sink is in standby/power off. Each bit
3568 corresponds to an input pad on the receiver. If an input pad
3569 cannot detect whether power is present, then the bit for that pad
3570 will be 0. This read-only control is applicable to DVI-D, HDMI and
3571 DisplayPort connectors.
3573 ``V4L2_CID_DV_RX_RGB_RANGE``
3576 enum v4l2_dv_rgb_range -
3577 Select the quantization range for RGB input. V4L2_DV_RANGE_AUTO
3578 follows the RGB quantization range specified in the standard for the
3579 video interface (ie. :ref:`cea861` for HDMI).
3580 V4L2_DV_RANGE_LIMITED and V4L2_DV_RANGE_FULL override the
3581 standard to be compatible with sources that have not implemented the
3582 standard correctly (unfortunately quite common for HDMI and DVI-D).
3583 Full range allows all possible values to be used whereas limited
3584 range sets the range to (16 << (N-8)) - (235 << (N-8)) where N is
3585 the number of bits per component. This control is applicable to VGA,
3586 DVI-A/D, HDMI and DisplayPort connectors.
3588 ``V4L2_CID_DV_RX_IT_CONTENT_TYPE``
3591 enum v4l2_dv_it_content_type -
3592 Reads the IT Content Type of the received video. This information is
3593 sent over HDMI and DisplayPort connectors as part of the AVI
3594 InfoFrame. The term 'IT Content' is used for content that originates
3595 from a computer as opposed to content from a TV broadcast or an
3596 analog source. See ``V4L2_CID_DV_TX_IT_CONTENT_TYPE`` for the
3597 available content types.
3602 FM Receiver Control Reference
3603 =============================
3605 The FM Receiver (FM_RX) class includes controls for common features of
3606 FM Reception capable devices.
3609 .. _fm-rx-control-id:
3614 ``V4L2_CID_FM_RX_CLASS (class)``
3615 The FM_RX class descriptor. Calling
3616 :ref:`VIDIOC_QUERYCTRL` for this control will
3617 return a description of this control class.
3619 ``V4L2_CID_RDS_RECEPTION (boolean)``
3620 Enables/disables RDS reception by the radio tuner
3622 ``V4L2_CID_RDS_RX_PTY (integer)``
3623 Gets RDS Programme Type field. This encodes up to 31 pre-defined
3626 ``V4L2_CID_RDS_RX_PS_NAME (string)``
3627 Gets the Programme Service name (PS_NAME). It is intended for
3628 static display on a receiver. It is the primary aid to listeners in
3629 programme service identification and selection. In Annex E of
3630 :ref:`iec62106`, the RDS specification, there is a full
3631 description of the correct character encoding for Programme Service
3632 name strings. Also from RDS specification, PS is usually a single
3633 eight character text. However, it is also possible to find receivers
3634 which can scroll strings sized as 8 x N characters. So, this control
3635 must be configured with steps of 8 characters. The result is it must
3636 always contain a string with size multiple of 8.
3638 ``V4L2_CID_RDS_RX_RADIO_TEXT (string)``
3639 Gets the Radio Text info. It is a textual description of what is
3640 being broadcasted. RDS Radio Text can be applied when broadcaster
3641 wishes to transmit longer PS names, programme-related information or
3642 any other text. In these cases, RadioText can be used in addition to
3643 ``V4L2_CID_RDS_RX_PS_NAME``. The encoding for Radio Text strings is
3644 also fully described in Annex E of :ref:`iec62106`. The length of
3645 Radio Text strings depends on which RDS Block is being used to
3646 transmit it, either 32 (2A block) or 64 (2B block). However, it is
3647 also possible to find receivers which can scroll strings sized as 32
3648 x N or 64 x N characters. So, this control must be configured with
3649 steps of 32 or 64 characters. The result is it must always contain a
3650 string with size multiple of 32 or 64.
3652 ``V4L2_CID_RDS_RX_TRAFFIC_ANNOUNCEMENT (boolean)``
3653 If set, then a traffic announcement is in progress.
3655 ``V4L2_CID_RDS_RX_TRAFFIC_PROGRAM (boolean)``
3656 If set, then the tuned programme carries traffic announcements.
3658 ``V4L2_CID_RDS_RX_MUSIC_SPEECH (boolean)``
3659 If set, then this channel broadcasts music. If cleared, then it
3660 broadcasts speech. If the transmitter doesn't make this distinction,
3661 then it will be set.
3663 ``V4L2_CID_TUNE_DEEMPHASIS``
3666 enum v4l2_deemphasis -
3667 Configures the de-emphasis value for reception. A de-emphasis filter
3668 is applied to the broadcast to accentuate the high audio
3669 frequencies. Depending on the region, a time constant of either 50
3670 or 75 useconds is used. The enum v4l2_deemphasis defines possible
3671 values for de-emphasis. Here they are:
3679 * - ``V4L2_DEEMPHASIS_DISABLED``
3680 - No de-emphasis is applied.
3681 * - ``V4L2_DEEMPHASIS_50_uS``
3682 - A de-emphasis of 50 uS is used.
3683 * - ``V4L2_DEEMPHASIS_75_uS``
3684 - A de-emphasis of 75 uS is used.
3689 .. _detect-controls:
3691 Detect Control Reference
3692 ========================
3694 The Detect class includes controls for common features of various motion
3695 or object detection capable devices.
3698 .. _detect-control-id:
3703 ``V4L2_CID_DETECT_CLASS (class)``
3704 The Detect class descriptor. Calling
3705 :ref:`VIDIOC_QUERYCTRL` for this control will
3706 return a description of this control class.
3708 ``V4L2_CID_DETECT_MD_MODE (menu)``
3709 Sets the motion detection mode.
3711 .. tabularcolumns:: |p{7.5cm}|p{10.0cm}|
3717 * - ``V4L2_DETECT_MD_MODE_DISABLED``
3718 - Disable motion detection.
3719 * - ``V4L2_DETECT_MD_MODE_GLOBAL``
3720 - Use a single motion detection threshold.
3721 * - ``V4L2_DETECT_MD_MODE_THRESHOLD_GRID``
3722 - The image is divided into a grid, each cell with its own motion
3723 detection threshold. These thresholds are set through the
3724 ``V4L2_CID_DETECT_MD_THRESHOLD_GRID`` matrix control.
3725 * - ``V4L2_DETECT_MD_MODE_REGION_GRID``
3726 - The image is divided into a grid, each cell with its own region
3727 value that specifies which per-region motion detection thresholds
3728 should be used. Each region has its own thresholds. How these
3729 per-region thresholds are set up is driver-specific. The region
3730 values for the grid are set through the
3731 ``V4L2_CID_DETECT_MD_REGION_GRID`` matrix control.
3735 ``V4L2_CID_DETECT_MD_GLOBAL_THRESHOLD (integer)``
3736 Sets the global motion detection threshold to be used with the
3737 ``V4L2_DETECT_MD_MODE_GLOBAL`` motion detection mode.
3739 ``V4L2_CID_DETECT_MD_THRESHOLD_GRID (__u16 matrix)``
3740 Sets the motion detection thresholds for each cell in the grid. To
3741 be used with the ``V4L2_DETECT_MD_MODE_THRESHOLD_GRID`` motion
3742 detection mode. Matrix element (0, 0) represents the cell at the
3743 top-left of the grid.
3745 ``V4L2_CID_DETECT_MD_REGION_GRID (__u8 matrix)``
3746 Sets the motion detection region value for each cell in the grid. To
3747 be used with the ``V4L2_DETECT_MD_MODE_REGION_GRID`` motion
3748 detection mode. Matrix element (0, 0) represents the cell at the
3749 top-left of the grid.
3752 .. _rf-tuner-controls:
3754 RF Tuner Control Reference
3755 ==========================
3757 The RF Tuner (RF_TUNER) class includes controls for common features of
3758 devices having RF tuner.
3760 In this context, RF tuner is radio receiver circuit between antenna and
3761 demodulator. It receives radio frequency (RF) from the antenna and
3762 converts that received signal to lower intermediate frequency (IF) or
3763 baseband frequency (BB). Tuners that could do baseband output are often
3764 called Zero-IF tuners. Older tuners were typically simple PLL tuners
3765 inside a metal box, whilst newer ones are highly integrated chips
3766 without a metal box "silicon tuners". These controls are mostly
3767 applicable for new feature rich silicon tuners, just because older
3768 tuners does not have much adjustable features.
3770 For more information about RF tuners see
3771 `Tuner (radio) <http://en.wikipedia.org/wiki/Tuner_%28radio%29>`__
3772 and `RF front end <http://en.wikipedia.org/wiki/RF_front_end>`__
3776 .. _rf-tuner-control-id:
3778 RF_TUNER Control IDs
3779 --------------------
3781 ``V4L2_CID_RF_TUNER_CLASS (class)``
3782 The RF_TUNER class descriptor. Calling
3783 :ref:`VIDIOC_QUERYCTRL` for this control will
3784 return a description of this control class.
3786 ``V4L2_CID_RF_TUNER_BANDWIDTH_AUTO (boolean)``
3787 Enables/disables tuner radio channel bandwidth configuration. In
3788 automatic mode bandwidth configuration is performed by the driver.
3790 ``V4L2_CID_RF_TUNER_BANDWIDTH (integer)``
3791 Filter(s) on tuner signal path are used to filter signal according
3792 to receiving party needs. Driver configures filters to fulfill
3793 desired bandwidth requirement. Used when
3794 V4L2_CID_RF_TUNER_BANDWIDTH_AUTO is not set. Unit is in Hz. The
3795 range and step are driver-specific.
3797 ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO (boolean)``
3798 Enables/disables LNA automatic gain control (AGC)
3800 ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO (boolean)``
3801 Enables/disables mixer automatic gain control (AGC)
3803 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO (boolean)``
3804 Enables/disables IF automatic gain control (AGC)
3806 ``V4L2_CID_RF_TUNER_RF_GAIN (integer)``
3807 The RF amplifier is the very first amplifier on the receiver signal
3808 path, just right after the antenna input. The difference between the
3809 LNA gain and the RF gain in this document is that the LNA gain is
3810 integrated in the tuner chip while the RF gain is a separate chip.
3811 There may be both RF and LNA gain controls in the same device. The
3812 range and step are driver-specific.
3814 ``V4L2_CID_RF_TUNER_LNA_GAIN (integer)``
3815 LNA (low noise amplifier) gain is first gain stage on the RF tuner
3816 signal path. It is located very close to tuner antenna input. Used
3817 when ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO`` is not set. See
3818 ``V4L2_CID_RF_TUNER_RF_GAIN`` to understand how RF gain and LNA gain
3819 differs from the each others. The range and step are
3822 ``V4L2_CID_RF_TUNER_MIXER_GAIN (integer)``
3823 Mixer gain is second gain stage on the RF tuner signal path. It is
3824 located inside mixer block, where RF signal is down-converted by the
3825 mixer. Used when ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO`` is not set.
3826 The range and step are driver-specific.
3828 ``V4L2_CID_RF_TUNER_IF_GAIN (integer)``
3829 IF gain is last gain stage on the RF tuner signal path. It is
3830 located on output of RF tuner. It controls signal level of
3831 intermediate frequency output or baseband output. Used when
3832 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO`` is not set. The range and step
3833 are driver-specific.
3835 ``V4L2_CID_RF_TUNER_PLL_LOCK (boolean)``
3836 Is synthesizer PLL locked? RF tuner is receiving given frequency
3837 when that control is set. This is a read-only control.
3840 This control may be changed to a menu control in the future, if more
3841 options are required.