요약·해설과 원문, 전문 번역을 서로 분리했습니다. API 이름, symbol, source path는 원문 표기를 사용합니다.
1. 요약·해설
원문의 핵심 논리와 kernel programming 관점의 보충 설명입니다. 아래의 전문 번역과는 별도로 작성했습니다.
2. 영어 원문 전체
번역 기준이 된 Linux v6.18.37 원문입니다. 줄 번호는 이 버전의 파일 좌표입니다.
원문 전체 펼치기
1
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later OR GPL-2.0
3
.. c:namespace:: dtv.legacy.video
5
.. _dvb_video:
7
================
8
DVB Video Device
9
================
11
.. attention:: Do **not** use in new drivers!
12
See: :ref:`legacy_dvb_decoder_notes`
14
The DVB video device controls the MPEG2 video decoder of the DVB
15
hardware. It can be accessed through ``/dev/dvb/adapter0/video0``. Data
16
types and ioctl definitions can be accessed by including
17
``linux/dvb/video.h`` in your application.
19
Note that the DVB video device only controls decoding of the MPEG video
20
stream, not its presentation on the TV or computer screen. On PCs this
21
is typically handled by an associated video4linux device, e.g.
22
``/dev/video``, which allows scaling and defining output windows.
24
Most DVB cards don’t have their own MPEG decoder, which results in the
25
omission of the audio and video device as well as the video4linux
26
device.
28
These ioctls were also used by V4L2 to control MPEG decoders implemented
29
in V4L2. The use of these ioctls for that purpose has been made obsolete
30
and proper V4L2 ioctls or controls have been created to replace that
31
functionality. Use :ref:`V4L2 ioctls<video>` for new drivers!
34
Video Data Types
35
================
39
video_format_t
40
--------------
42
Synopsis
43
~~~~~~~~
45
.. code-block:: c
47
typedef enum {
48
VIDEO_FORMAT_4_3,
49
VIDEO_FORMAT_16_9,
50
VIDEO_FORMAT_221_1
51
} video_format_t;
53
Constants
54
~~~~~~~~~
56
.. flat-table::
57
:header-rows: 0
58
:stub-columns: 0
60
- ..
62
- ``VIDEO_FORMAT_4_3``
64
- Select 4:3 format.
66
- ..
68
- ``VIDEO_FORMAT_16_9``
70
- Select 16:9 format.
72
- ..
74
- ``VIDEO_FORMAT_221_1``
76
- Select 2.21:1 format.
78
Description
79
~~~~~~~~~~~
81
The ``video_format_t`` data type
82
is used in the `VIDEO_SET_FORMAT`_ function to tell the driver which
83
aspect ratio the output hardware (e.g. TV) has. It is also used in the
84
data structures `video_status`_ returned by `VIDEO_GET_STATUS`_
85
and `video_event`_ returned by `VIDEO_GET_EVENT`_ which report
86
about the display format of the current video stream.
89
-----
92
video_displayformat_t
93
---------------------
95
Synopsis
96
~~~~~~~~
98
.. code-block:: c
100
typedef enum {
101
VIDEO_PAN_SCAN,
102
VIDEO_LETTER_BOX,
103
VIDEO_CENTER_CUT_OUT
104
} video_displayformat_t;
106
Constants
107
~~~~~~~~~
109
.. flat-table::
110
:header-rows: 0
111
:stub-columns: 0
113
- ..
115
- ``VIDEO_PAN_SCAN``
117
- Use pan and scan format.
119
- ..
121
- ``VIDEO_LETTER_BOX``
123
- Use letterbox format.
125
- ..
127
- ``VIDEO_CENTER_CUT_OUT``
129
- Use center cut out format.
131
Description
132
~~~~~~~~~~~
134
In case the display format of the video stream and of the display
135
hardware differ the application has to specify how to handle the
136
cropping of the picture. This can be done using the
137
`VIDEO_SET_DISPLAY_FORMAT`_ call which accepts this enum as argument.
140
-----
143
video_size_t
144
------------
146
Synopsis
147
~~~~~~~~
149
.. code-block:: c
151
typedef struct {
152
int w;
153
int h;
154
video_format_t aspect_ratio;
155
} video_size_t;
157
Variables
158
~~~~~~~~~
160
.. flat-table::
161
:header-rows: 0
162
:stub-columns: 0
164
- ..
166
- ``int w``
168
- Video width in pixels.
170
- ..
172
- ``int h``
174
- Video height in pixels.
176
- ..
178
- `video_format_t`_ ``aspect_ratio``
180
- Aspect ratio.
182
Description
183
~~~~~~~~~~~
185
Used in the struct `video_event`_. It stores the resolution and
186
aspect ratio of the video.
189
-----
192
video_stream_source_t
193
---------------------
195
Synopsis
196
~~~~~~~~
198
.. code-block:: c
200
typedef enum {
201
VIDEO_SOURCE_DEMUX,
202
VIDEO_SOURCE_MEMORY
203
} video_stream_source_t;
205
Constants
206
~~~~~~~~~
208
.. flat-table::
209
:header-rows: 0
210
:stub-columns: 0
212
- ..
214
- ``VIDEO_SOURCE_DEMUX``
216
- :cspan:`1` Select the demux as the main source.
218
- ..
220
- ``VIDEO_SOURCE_MEMORY``
222
- If this source is selected, the stream
223
comes from the user through the write
224
system call.
226
Description
227
~~~~~~~~~~~
229
The video stream source is set through the `VIDEO_SELECT_SOURCE`_ call
230
and can take the following values, depending on whether we are replaying
231
from an internal (demuxer) or external (user write) source.
232
VIDEO_SOURCE_DEMUX selects the demultiplexer (fed either by the
233
frontend or the DVR device) as the source of the video stream. If
234
VIDEO_SOURCE_MEMORY is selected the stream comes from the application
235
through the `write()`_ system call.
238
-----
241
video_play_state_t
242
------------------
244
Synopsis
245
~~~~~~~~
247
.. code-block:: c
249
typedef enum {
250
VIDEO_STOPPED,
251
VIDEO_PLAYING,
252
VIDEO_FREEZED
253
} video_play_state_t;
255
Constants
256
~~~~~~~~~
258
.. flat-table::
259
:header-rows: 0
260
:stub-columns: 0
262
- ..
264
- ``VIDEO_STOPPED``
266
- Video is stopped.
268
- ..
270
- ``VIDEO_PLAYING``
272
- Video is currently playing.
274
- ..
276
- ``VIDEO_FREEZED``
278
- Video is frozen.
280
Description
281
~~~~~~~~~~~
283
This values can be returned by the `VIDEO_GET_STATUS`_ call
284
representing the state of video playback.
287
-----
290
struct video_command
291
--------------------
293
Synopsis
294
~~~~~~~~
296
.. code-block:: c
298
struct video_command {
299
__u32 cmd;
300
__u32 flags;
301
union {
302
struct {
303
__u64 pts;
304
} stop;
306
struct {
307
__s32 speed;
308
__u32 format;
309
} play;
311
struct {
312
__u32 data[16];
313
} raw;
314
};
315
};
318
Variables
319
~~~~~~~~~
321
.. flat-table::
322
:header-rows: 0
323
:stub-columns: 0
325
- ..
327
- ``__u32 cmd``
329
- `Decoder command`_
331
- ..
333
- ``__u32 flags``
335
- Flags for the `Decoder command`_.
337
- ..
339
- ``struct stop``
341
- ``__u64 pts``
343
- MPEG PTS
345
- ..
347
- :rspan:`5` ``stuct play``
349
- :rspan:`4` ``__s32 speed``
351
- 0 or 1000 specifies normal speed,
353
- ..
355
- 1: specifies forward single stepping,
357
- ..
359
- -1: specifies backward single stepping,
361
- ..
363
- >1: playback at speed / 1000 of the normal speed
365
- ..
367
- <-1: reverse playback at ( -speed / 1000 ) of the normal speed.
369
- ..
371
- ``__u32 format``
373
- `Play input formats`_
375
- ..
377
- ``__u32 data[16]``
379
- Reserved
381
Description
382
~~~~~~~~~~~
384
The structure must be zeroed before use by the application. This ensures
385
it can be extended safely in the future.
388
-----
391
Predefined decoder commands and flags
392
-------------------------------------
394
Synopsis
395
~~~~~~~~
397
.. code-block:: c
399
#define VIDEO_CMD_PLAY (0)
400
#define VIDEO_CMD_STOP (1)
401
#define VIDEO_CMD_FREEZE (2)
402
#define VIDEO_CMD_CONTINUE (3)
404
#define VIDEO_CMD_FREEZE_TO_BLACK (1 << 0)
406
#define VIDEO_CMD_STOP_TO_BLACK (1 << 0)
407
#define VIDEO_CMD_STOP_IMMEDIATELY (1 << 1)
409
#define VIDEO_PLAY_FMT_NONE (0)
410
#define VIDEO_PLAY_FMT_GOP (1)
412
#define VIDEO_VSYNC_FIELD_UNKNOWN (0)
413
#define VIDEO_VSYNC_FIELD_ODD (1)
414
#define VIDEO_VSYNC_FIELD_EVEN (2)
415
#define VIDEO_VSYNC_FIELD_PROGRESSIVE (3)
417
Constants
418
~~~~~~~~~
420
.. flat-table::
421
:header-rows: 0
422
:stub-columns: 0
424
- ..
426
- :rspan:`3` _`Decoder command`
428
- ``VIDEO_CMD_PLAY``
430
- Start playback.
432
- ..
434
- ``VIDEO_CMD_STOP``
436
- Stop playback.
438
- ..
440
- ``VIDEO_CMD_FREEZE``
442
- Freeze playback.
444
- ..
446
- ``VIDEO_CMD_CONTINUE``
448
- Continue playback after freeze.
450
- ..
452
- Flags for ``VIDEO_CMD_FREEZE``
454
- ``VIDEO_CMD_FREEZE_TO_BLACK``
456
- Show black picture on freeze.
458
- ..
460
- :rspan:`1` Flags for ``VIDEO_CMD_STOP``
462
- ``VIDEO_CMD_STOP_TO_BLACK``
464
- Show black picture on stop.
466
- ..
468
- ``VIDEO_CMD_STOP_IMMEDIATELY``
470
- Stop immediately, without emptying buffers.
472
- ..
474
- :rspan:`1` _`Play input formats`
476
- ``VIDEO_PLAY_FMT_NONE``
478
- The decoder has no special format requirements
480
- ..
482
- ``VIDEO_PLAY_FMT_GOP``
484
- The decoder requires full GOPs
486
- ..
488
- :rspan:`3` Field order
490
- ``VIDEO_VSYNC_FIELD_UNKNOWN``
492
- FIELD_UNKNOWN can be used if the hardware does not know
493
whether the Vsync is for an odd, even or progressive
494
(i.e. non-interlaced) field.
496
- ..
498
- ``VIDEO_VSYNC_FIELD_ODD``
500
- Vsync is for an odd field.
502
- ..
504
- ``VIDEO_VSYNC_FIELD_EVEN``
506
- Vsync is for an even field.
508
- ..
510
- ``VIDEO_VSYNC_FIELD_PROGRESSIVE``
512
- progressive (i.e. non-interlaced)
515
-----
518
video_event
519
-----------
521
Synopsis
522
~~~~~~~~
524
.. code-block:: c
526
struct video_event {
527
__s32 type;
528
#define VIDEO_EVENT_SIZE_CHANGED 1
529
#define VIDEO_EVENT_FRAME_RATE_CHANGED 2
530
#define VIDEO_EVENT_DECODER_STOPPED 3
531
#define VIDEO_EVENT_VSYNC 4
532
long timestamp;
533
union {
534
video_size_t size;
535
unsigned int frame_rate;
536
unsigned char vsync_field;
537
} u;
538
};
540
Variables
541
~~~~~~~~~
543
.. flat-table::
544
:header-rows: 0
545
:stub-columns: 0
547
- ..
549
- :rspan:`4` ``__s32 type``
551
- :cspan:`1` Event type.
553
- ..
555
- ``VIDEO_EVENT_SIZE_CHANGED``
557
- Size changed.
559
- ..
561
- ``VIDEO_EVENT_FRAME_RATE_CHANGED``
563
- Framerate changed.
565
- ..
567
- ``VIDEO_EVENT_DECODER_STOPPED``
569
- Decoder stopped.
571
- ..
573
- ``VIDEO_EVENT_VSYNC``
575
- Vsync occurred.
577
- ..
579
- ``long timestamp``
581
- :cspan:`1` MPEG PTS at occurrence.
583
- ..
585
- :rspan:`2` ``union u``
587
- `video_size_t`_ size
589
- Resolution and aspect ratio of the video.
591
- ..
593
- ``unsigned int frame_rate``
595
- in frames per 1000sec
597
- ..
599
- ``unsigned char vsync_field``
601
- | unknown / odd / even / progressive
602
| See: `Predefined decoder commands and flags`_
604
Description
605
~~~~~~~~~~~
607
This is the structure of a video event as it is returned by the
608
`VIDEO_GET_EVENT`_ call. See there for more details.
611
-----
614
video_status
615
------------
617
Synopsis
618
~~~~~~~~
620
The `VIDEO_GET_STATUS`_ call returns the following structure informing
621
about various states of the playback operation.
623
.. code-block:: c
625
struct video_status {
626
int video_blank;
627
video_play_state_t play_state;
628
video_stream_source_t stream_source;
629
video_format_t video_format;
630
video_displayformat_t display_format;
631
};
633
Variables
634
~~~~~~~~~
636
.. flat-table::
637
:header-rows: 0
638
:stub-columns: 0
640
- ..
642
- :rspan:`2` ``int video_blank``
644
- :cspan:`1` Show blank video on freeze?
646
- ..
648
- TRUE ( != 0 )
650
- Blank screen when freeze.
652
- ..
654
- FALSE ( == 0 )
656
- Show last decoded frame.
658
- ..
660
- `video_play_state_t`_ ``play_state``
662
- Current state of playback.
664
- ..
666
- `video_stream_source_t`_ ``stream_source``
668
- Current source (demux/memory).
670
- ..
672
- `video_format_t`_ ``video_format``
674
- Current aspect ratio of stream.
676
- ..
678
- `video_displayformat_t`_ ``display_format``
680
- Applied cropping mode.
682
Description
683
~~~~~~~~~~~
685
If ``video_blank`` is set ``TRUE`` video will be blanked out if the
686
channel is changed or if playback is stopped. Otherwise, the last picture
687
will be displayed. ``play_state`` indicates if the video is currently
688
frozen, stopped, or being played back. The ``stream_source`` corresponds
689
to the selected source for the video stream. It can come either from the
690
demultiplexer or from memory. The ``video_format`` indicates the aspect
691
ratio (one of 4:3 or 16:9) of the currently played video stream.
692
Finally, ``display_format`` corresponds to the applied cropping mode in
693
case the source video format is not the same as the format of the output
694
device.
697
-----
700
video_still_picture
701
-------------------
703
Synopsis
704
~~~~~~~~
706
.. code-block:: c
708
struct video_still_picture {
709
char *iFrame;
710
int32_t size;
711
};
713
Variables
714
~~~~~~~~~
716
.. flat-table::
717
:header-rows: 0
718
:stub-columns: 0
720
- ..
722
- ``char *iFrame``
724
- Pointer to a single iframe in memory.
726
- ..
728
- ``int32_t size``
730
- Size of the iframe.
733
Description
734
~~~~~~~~~~~
736
An I-frame displayed via the `VIDEO_STILLPICTURE`_ call is passed on
737
within this structure.
740
-----
743
video capabilities
744
------------------
746
Synopsis
747
~~~~~~~~
749
.. code-block:: c
751
#define VIDEO_CAP_MPEG1 1
752
#define VIDEO_CAP_MPEG2 2
753
#define VIDEO_CAP_SYS 4
754
#define VIDEO_CAP_PROG 8
756
Constants
757
~~~~~~~~~
758
Bit definitions for capabilities:
760
.. flat-table::
761
:header-rows: 0
762
:stub-columns: 0
764
- ..
766
- ``VIDEO_CAP_MPEG1``
768
- :cspan:`1` The hardware can decode MPEG1.
770
- ..
772
- ``VIDEO_CAP_MPEG2``
774
- The hardware can decode MPEG2.
776
- ..
778
- ``VIDEO_CAP_SYS``
780
- The video device accepts system stream.
782
You still have to open the video and the audio device
783
but only send the stream to the video device.
785
- ..
787
- ``VIDEO_CAP_PROG``
789
- The video device accepts program stream.
791
You still have to open the video and the audio device
792
but only send the stream to the video device.
794
Description
795
~~~~~~~~~~~
797
A call to `VIDEO_GET_CAPABILITIES`_ returns an unsigned integer with the
798
following bits set according to the hardware's capabilities.
801
-----
804
Video Function Calls
805
====================
808
VIDEO_STOP
809
----------
811
Synopsis
812
~~~~~~~~
814
.. c:macro:: VIDEO_STOP
816
.. code-block:: c
818
int ioctl(fd, VIDEO_STOP, int mode)
820
Arguments
821
~~~~~~~~~
823
.. flat-table::
824
:header-rows: 0
825
:stub-columns: 0
827
- ..
829
- ``int fd``
831
- :cspan:`1` File descriptor returned by a previous call
832
to `open()`_.
834
- ..
836
- ``int request``
838
- :cspan:`1` Equals ``VIDEO_STOP`` for this command.
840
- ..
842
- :rspan:`2` ``int mode``
844
- :cspan:`1` Indicates how the screen shall be handled.
846
- ..
848
- TRUE ( != 0 )
850
- Blank screen when stop.
852
- ..
854
- FALSE ( == 0 )
856
- Show last decoded frame.
858
Description
859
~~~~~~~~~~~
861
.. attention:: Do **not** use in new drivers!
862
See: :ref:`legacy_dvb_decoder_notes`
864
This ioctl is for Digital TV devices only. To control a V4L2 decoder use
865
the V4L2 :ref:`VIDIOC_DECODER_CMD` instead.
867
This ioctl call asks the Video Device to stop playing the current
868
stream. Depending on the input parameter, the screen can be blanked out
869
or displaying the last decoded frame.
871
Return Value
872
~~~~~~~~~~~~
874
On success 0 is returned, on error -1 and the ``errno`` variable is set
875
appropriately. The generic error codes are described at the
876
:ref:`Generic Error Codes <gen-errors>` chapter.
879
-----
882
VIDEO_PLAY
883
----------
885
Synopsis
886
~~~~~~~~
888
.. c:macro:: VIDEO_PLAY
890
.. code-block:: c
892
int ioctl(fd, VIDEO_PLAY)
894
Arguments
895
~~~~~~~~~
897
.. flat-table::
898
:header-rows: 0
899
:stub-columns: 0
901
- ..
903
- ``int fd``
905
- :cspan:`1` File descriptor returned by a previous call
906
to `open()`_.
908
- ..
910
- ``int request``
912
- Equals ``VIDEO_PLAY`` for this command.
914
Description
915
~~~~~~~~~~~
917
.. attention:: Do **not** use in new drivers!
918
See: :ref:`legacy_dvb_decoder_notes`
920
This ioctl is for Digital TV devices only. To control a V4L2 decoder use
921
the V4L2 :ref:`VIDIOC_DECODER_CMD` instead.
923
This ioctl call asks the Video Device to start playing a video stream
924
from the selected source.
926
Return Value
927
~~~~~~~~~~~~
929
On success 0 is returned, on error -1 and the ``errno`` variable is set
930
appropriately. The generic error codes are described at the
931
:ref:`Generic Error Codes <gen-errors>` chapter.
934
-----
937
VIDEO_FREEZE
938
------------
940
Synopsis
941
~~~~~~~~
943
.. c:macro:: VIDEO_FREEZE
945
.. code-block:: c
947
int ioctl(fd, VIDEO_FREEZE)
949
Arguments
950
~~~~~~~~~
952
.. flat-table::
953
:header-rows: 0
954
:stub-columns: 0
956
- ..
958
- ``int fd``
960
- :cspan:`1` File descriptor returned by a previous call
961
to `open()`_.
963
- ..
965
- ``int request``
967
- Equals ``VIDEO_FREEZE`` for this command.
969
Description
970
~~~~~~~~~~~
972
.. attention:: Do **not** use in new drivers!
973
See: :ref:`legacy_dvb_decoder_notes`
975
This ioctl is for Digital TV devices only. To control a V4L2 decoder use
976
the V4L2 :ref:`VIDIOC_DECODER_CMD` instead.
978
This ioctl call suspends the live video stream being played, if
979
VIDEO_SOURCE_DEMUX is selected. Decoding and playing are frozen.
980
It is then possible to restart the decoding and playing process of the
981
video stream using the `VIDEO_CONTINUE`_ command.
982
If VIDEO_SOURCE_MEMORY is selected in the ioctl call
983
`VIDEO_SELECT_SOURCE`_, the Digital TV subsystem will not decode any more
984
data until the ioctl call `VIDEO_CONTINUE`_ or `VIDEO_PLAY`_ is performed.
986
Return Value
987
~~~~~~~~~~~~
989
On success 0 is returned, on error -1 and the ``errno`` variable is set
990
appropriately. The generic error codes are described at the
991
:ref:`Generic Error Codes <gen-errors>` chapter.
994
-----
997
VIDEO_CONTINUE
998
--------------
1000
Synopsis
1001
~~~~~~~~
1003
.. c:macro:: VIDEO_CONTINUE
1005
.. code-block:: c
1007
int ioctl(fd, VIDEO_CONTINUE)
1009
Arguments
1010
~~~~~~~~~
1012
.. flat-table::
1013
:header-rows: 0
1014
:stub-columns: 0
1016
- ..
1018
- ``int fd``
1020
- :cspan:`1` File descriptor returned by a previous call
1021
to `open()`_.
1023
- ..
1025
- ``int request``
1027
- Equals ``VIDEO_CONTINUE`` for this command.
1029
Description
1030
~~~~~~~~~~~
1032
.. attention:: Do **not** use in new drivers!
1033
See: :ref:`legacy_dvb_decoder_notes`
1035
This ioctl is for Digital TV devices only. To control a V4L2 decoder use
1036
the V4L2 :ref:`VIDIOC_DECODER_CMD` instead.
1038
This ioctl call restarts decoding and playing processes of the video
1039
stream which was played before a call to `VIDEO_FREEZE`_ was made.
1041
Return Value
1042
~~~~~~~~~~~~
1044
On success 0 is returned, on error -1 and the ``errno`` variable is set
1045
appropriately. The generic error codes are described at the
1046
:ref:`Generic Error Codes <gen-errors>` chapter.
1049
-----
1052
VIDEO_SELECT_SOURCE
1053
-------------------
1055
Synopsis
1056
~~~~~~~~
1058
.. c:macro:: VIDEO_SELECT_SOURCE
1060
.. code-block:: c
1062
int ioctl(fd, VIDEO_SELECT_SOURCE, video_stream_source_t source)
1064
Arguments
1065
~~~~~~~~~
1067
.. flat-table::
1068
:header-rows: 0
1069
:stub-columns: 0
1071
- ..
1073
- ``int fd``
1075
- :cspan:`1` File descriptor returned by a previous call
1076
to `open()`_.
1078
- ..
1080
- ``int request``
1082
- Equals ``VIDEO_SELECT_SOURCE`` for this command.
1084
- ..
1086
- `video_stream_source_t`_ ``source``
1088
- Indicates which source shall be used for the Video stream.
1090
Description
1091
~~~~~~~~~~~
1093
.. attention:: Do **not** use in new drivers!
1094
See: :ref:`legacy_dvb_decoder_notes`
1096
This ioctl is for Digital TV devices only. This ioctl was also supported
1097
by the V4L2 ivtv driver, but that has been replaced by the ivtv-specific
1098
``IVTV_IOC_PASSTHROUGH_MODE`` ioctl.
1100
This ioctl call informs the video device which source shall be used for
1101
the input data. The possible sources are demux or memory. If memory is
1102
selected, the data is fed to the video device through the write command
1103
using the struct `video_stream_source_t`_. If demux is selected, the data
1104
is directly transferred from the onboard demux-device to the decoder.
1106
The data fed to the decoder is also controlled by the PID-filter.
1107
Output selection: :c:type:`dmx_output` ``DMX_OUT_DECODER``.
1110
Return Value
1111
~~~~~~~~~~~~
1113
On success 0 is returned, on error -1 and the ``errno`` variable is set
1114
appropriately. The generic error codes are described at the
1115
:ref:`Generic Error Codes <gen-errors>` chapter.
1118
-----
1121
VIDEO_SET_BLANK
1122
---------------
1124
Synopsis
1125
~~~~~~~~
1127
.. c:macro:: VIDEO_SET_BLANK
1129
.. code-block:: c
1131
int ioctl(fd, VIDEO_SET_BLANK, int mode)
1133
Arguments
1134
~~~~~~~~~
1136
.. flat-table::
1137
:header-rows: 0
1138
:stub-columns: 0
1140
- ..
1142
- ``int fd``
1144
- :cspan:`1` File descriptor returned by a previous call
1145
to `open()`_.
1147
- ..
1149
- ``int request``
1151
- :cspan:`1` Equals ``VIDEO_SET_BLANK`` for this command.
1153
- ..
1155
- :rspan:`2` ``int mode``
1157
- :cspan:`1` Indicates if the screen shall be blanked.
1159
- ..
1161
- TRUE ( != 0 )
1163
- Blank screen when stop.
1165
- ..
1167
- FALSE ( == 0 )
1169
- Show last decoded frame.
1171
Description
1172
~~~~~~~~~~~
1174
.. attention:: Do **not** use in new drivers!
1175
See: :ref:`legacy_dvb_decoder_notes`
1177
This ioctl call asks the Video Device to blank out the picture.
1179
Return Value
1180
~~~~~~~~~~~~
1182
On success 0 is returned, on error -1 and the ``errno`` variable is set
1183
appropriately. The generic error codes are described at the
1184
:ref:`Generic Error Codes <gen-errors>` chapter.
1187
-----
1190
VIDEO_GET_STATUS
1191
----------------
1193
Synopsis
1194
~~~~~~~~
1196
.. c:macro:: VIDEO_GET_STATUS
1198
.. code-block:: c
1200
int ioctl(fd, int request = VIDEO_GET_STATUS,
1201
struct video_status *status)
1203
Arguments
1204
~~~~~~~~~
1206
.. flat-table::
1207
:header-rows: 0
1208
:stub-columns: 0
1210
- ..
1212
- ``int fd``
1214
- :cspan:`1` File descriptor returned by a previous call
1215
to `open()`_.
1217
- ..
1219
- ``int request``
1221
- Equals ``VIDEO_GET_STATUS`` for this command.
1223
- ..
1225
- ``struct`` `video_status`_ ``*status``
1227
- Returns the current status of the Video Device.
1229
Description
1230
~~~~~~~~~~~
1232
.. attention:: Do **not** use in new drivers!
1233
See: :ref:`legacy_dvb_decoder_notes`
1235
This ioctl call asks the Video Device to return the current status of
1236
the device.
1238
Return Value
1239
~~~~~~~~~~~~
1241
On success 0 is returned, on error -1 and the ``errno`` variable is set
1242
appropriately. The generic error codes are described at the
1243
:ref:`Generic Error Codes <gen-errors>` chapter.
1246
-----
1249
VIDEO_GET_EVENT
1250
---------------
1252
Synopsis
1253
~~~~~~~~
1255
.. c:macro:: VIDEO_GET_EVENT
1257
.. code-block:: c
1259
int ioctl(fd, int request = VIDEO_GET_EVENT,
1260
struct video_event *ev)
1262
Arguments
1263
~~~~~~~~~
1265
.. flat-table::
1266
:header-rows: 0
1267
:stub-columns: 0
1269
- ..
1271
- ``int fd``
1273
- :cspan:`1` File descriptor returned by a previous call
1274
to `open()`_.
1276
- ..
1278
- ``int request``
1280
- Equals ``VIDEO_GET_EVENT`` for this command.
1282
- ..
1284
- ``struct`` `video_event`_ ``*ev``
1286
- Points to the location where the event, if any, is to be stored.
1288
Description
1289
~~~~~~~~~~~
1291
.. attention:: Do **not** use in new drivers!
1292
See: :ref:`legacy_dvb_decoder_notes`
1294
This ioctl is for DVB devices only. To get events from a V4L2 decoder
1295
use the V4L2 :ref:`VIDIOC_DQEVENT` ioctl instead.
1297
This ioctl call returns an event of type `video_event`_ if available. A
1298
certain number of the latest events will be cued and returned in order of
1299
occurrence. Older events may be discarded if not fetched in time. If
1300
an event is not available, the behavior depends on whether the device is
1301
in blocking or non-blocking mode. In the latter case, the call fails
1302
immediately with errno set to ``EWOULDBLOCK``. In the former case, the
1303
call blocks until an event becomes available. The standard Linux poll()
1304
and/or select() system calls can be used with the device file descriptor
1305
to watch for new events. For select(), the file descriptor should be
1306
included in the exceptfds argument, and for poll(), POLLPRI should be
1307
specified as the wake-up condition. Read-only permissions are sufficient
1308
for this ioctl call.
1310
Return Value
1311
~~~~~~~~~~~~
1313
On success 0 is returned, on error -1 and the ``errno`` variable is set
1314
appropriately. The generic error codes are described at the
1315
:ref:`Generic Error Codes <gen-errors>` chapter.
1317
.. flat-table::
1318
:header-rows: 0
1319
:stub-columns: 0
1321
- ..
1323
- ``EWOULDBLOCK``
1325
- :cspan:`1` There is no event pending, and the device is in
1326
non-blocking mode.
1328
- ..
1330
- ``EOVERFLOW``
1332
- Overflow in event queue - one or more events were lost.
1335
-----
1338
VIDEO_SET_DISPLAY_FORMAT
1339
------------------------
1341
Synopsis
1342
~~~~~~~~
1344
.. c:macro:: VIDEO_SET_DISPLAY_FORMAT
1346
.. code-block:: c
1348
int ioctl(fd, int request = VIDEO_SET_DISPLAY_FORMAT,
1349
video_display_format_t format)
1351
Arguments
1352
~~~~~~~~~
1354
.. flat-table::
1355
:header-rows: 0
1356
:stub-columns: 0
1358
- ..
1360
- ``int fd``
1362
- :cspan:`1` File descriptor returned by a previous call
1363
to `open()`_.
1365
- ..
1367
- ``int request``
1369
- Equals ``VIDEO_SET_DISPLAY_FORMAT`` for this command.
1371
- ..
1373
- `video_displayformat_t`_ ``format``
1375
- Selects the video format to be used.
1377
Description
1378
~~~~~~~~~~~
1380
.. attention:: Do **not** use in new drivers!
1381
See: :ref:`legacy_dvb_decoder_notes`
1383
This ioctl call asks the Video Device to select the video format to be
1384
applied by the MPEG chip on the video.
1386
Return Value
1387
~~~~~~~~~~~~
1389
On success 0 is returned, on error -1 and the ``errno`` variable is set
1390
appropriately. The generic error codes are described at the
1391
:ref:`Generic Error Codes <gen-errors>` chapter.
1394
-----
1397
VIDEO_STILLPICTURE
1398
------------------
1400
Synopsis
1401
~~~~~~~~
1403
.. c:macro:: VIDEO_STILLPICTURE
1405
.. code-block:: c
1407
int ioctl(fd, int request = VIDEO_STILLPICTURE,
1408
struct video_still_picture *sp)
1410
Arguments
1411
~~~~~~~~~
1413
.. flat-table::
1414
:header-rows: 0
1415
:stub-columns: 0
1417
- ..
1419
- ``int fd``
1421
- :cspan:`1` File descriptor returned by a previous call
1422
to `open()`_.
1424
- ..
1426
- ``int request``
1428
- Equals ``VIDEO_STILLPICTURE`` for this command.
1430
- ..
1432
- ``struct`` `video_still_picture`_ ``*sp``
1434
- Pointer to the location where the struct with the I-frame
1435
and size is stored.
1437
Description
1438
~~~~~~~~~~~
1440
.. attention:: Do **not** use in new drivers!
1441
See: :ref:`legacy_dvb_decoder_notes`
1443
This ioctl call asks the Video Device to display a still picture
1444
(I-frame). The input data shall be the section of an elementary video
1445
stream containing an I-frame. Typically this section is extracted from a
1446
TS or PES recording. Resolution and codec (see `video capabilities`_) must
1447
be supported by the device. If the pointer is NULL, then the current
1448
displayed still picture is blanked.
1450
e.g. The AV7110 supports MPEG1 and MPEG2 with the common PAL-SD
1451
resolutions.
1453
Return Value
1454
~~~~~~~~~~~~
1456
On success 0 is returned, on error -1 and the ``errno`` variable is set
1457
appropriately. The generic error codes are described at the
1458
:ref:`Generic Error Codes <gen-errors>` chapter.
1461
-----
1464
VIDEO_FAST_FORWARD
1465
------------------
1467
Synopsis
1468
~~~~~~~~
1470
.. c:macro:: VIDEO_FAST_FORWARD
1472
.. code-block:: c
1474
int ioctl(fd, int request = VIDEO_FAST_FORWARD, int nFrames)
1476
Arguments
1477
~~~~~~~~~
1479
.. flat-table::
1480
:header-rows: 0
1481
:stub-columns: 0
1483
- ..
1485
- ``int fd``
1487
- :cspan:`1` File descriptor returned by a previous call
1488
to `open()`_.
1490
- ..
1492
- ``int request``
1494
- Equals ``VIDEO_FAST_FORWARD`` for this command.
1496
- ..
1498
- ``int nFrames``
1500
- The number of frames to skip.
1502
Description
1503
~~~~~~~~~~~
1505
.. attention:: Do **not** use in new drivers!
1506
See: :ref:`legacy_dvb_decoder_notes`
1508
This ioctl call asks the Video Device to skip decoding of N number of
1509
I-frames. This call can only be used if ``VIDEO_SOURCE_MEMORY`` is
1510
selected.
1512
Return Value
1513
~~~~~~~~~~~~
1515
On success 0 is returned, on error -1 and the ``errno`` variable is set
1516
appropriately. The generic error codes are described at the
1517
:ref:`Generic Error Codes <gen-errors>` chapter.
1519
.. flat-table::
1520
:header-rows: 0
1521
:stub-columns: 0
1523
- ..
1525
- ``EPERM``
1527
- Mode ``VIDEO_SOURCE_MEMORY`` not selected.
1530
-----
1533
VIDEO_SLOWMOTION
1534
----------------
1536
Synopsis
1537
~~~~~~~~
1539
.. c:macro:: VIDEO_SLOWMOTION
1541
.. code-block:: c
1543
int ioctl(fd, int request = VIDEO_SLOWMOTION, int nFrames)
1545
Arguments
1546
~~~~~~~~~
1548
.. flat-table::
1549
:header-rows: 0
1550
:stub-columns: 0
1552
- ..
1554
- ``int fd``
1556
- :cspan:`1` File descriptor returned by a previous call
1557
to `open()`_.
1559
- ..
1561
- ``int request``
1563
- Equals ``VIDEO_SLOWMOTION`` for this command.
1565
- ..
1567
- ``int nFrames``
1569
- The number of times to repeat each frame.
1571
Description
1572
~~~~~~~~~~~
1574
.. attention:: Do **not** use in new drivers!
1575
See: :ref:`legacy_dvb_decoder_notes`
1577
This ioctl call asks the video device to repeat decoding frames N number
1578
of times. This call can only be used if ``VIDEO_SOURCE_MEMORY`` is
1579
selected.
1581
Return Value
1582
~~~~~~~~~~~~
1584
On success 0 is returned, on error -1 and the ``errno`` variable is set
1585
appropriately. The generic error codes are described at the
1586
:ref:`Generic Error Codes <gen-errors>` chapter.
1588
.. flat-table::
1589
:header-rows: 0
1590
:stub-columns: 0
1592
- ..
1594
- ``EPERM``
1596
- Mode ``VIDEO_SOURCE_MEMORY`` not selected.
1599
-----
1602
VIDEO_GET_CAPABILITIES
1603
----------------------
1605
Synopsis
1606
~~~~~~~~
1608
.. c:macro:: VIDEO_GET_CAPABILITIES
1610
.. code-block:: c
1612
int ioctl(fd, int request = VIDEO_GET_CAPABILITIES, unsigned int *cap)
1614
Arguments
1615
~~~~~~~~~
1617
.. flat-table::
1618
:header-rows: 0
1619
:stub-columns: 0
1621
- ..
1623
- ``int fd``
1625
- :cspan:`1` File descriptor returned by a previous call
1626
to `open()`_.
1628
- ..
1630
- ``int request``
1632
- Equals ``VIDEO_GET_CAPABILITIES`` for this command.
1634
- ..
1636
- ``unsigned int *cap``
1638
- Pointer to a location where to store the capability information.
1640
Description
1641
~~~~~~~~~~~
1643
.. attention:: Do **not** use in new drivers!
1644
See: :ref:`legacy_dvb_decoder_notes`
1646
This ioctl call asks the video device about its decoding capabilities.
1647
On success it returns an integer which has bits set according to the
1648
defines in `video capabilities`_.
1650
Return Value
1651
~~~~~~~~~~~~
1653
On success 0 is returned, on error -1 and the ``errno`` variable is set
1654
appropriately. The generic error codes are described at the
1655
:ref:`Generic Error Codes <gen-errors>` chapter.
1658
-----
1661
VIDEO_CLEAR_BUFFER
1662
------------------
1664
Synopsis
1665
~~~~~~~~
1667
.. c:macro:: VIDEO_CLEAR_BUFFER
1669
.. code-block:: c
1671
int ioctl(fd, int request = VIDEO_CLEAR_BUFFER)
1673
Arguments
1674
~~~~~~~~~
1676
.. flat-table::
1677
:header-rows: 0
1678
:stub-columns: 0
1680
- ..
1682
- ``int fd``
1684
- :cspan:`1` File descriptor returned by a previous call
1685
to `open()`_.
1687
- ..
1689
- ``int request``
1691
- Equals ``VIDEO_CLEAR_BUFFER`` for this command.
1693
Description
1694
~~~~~~~~~~~
1696
.. attention:: Do **not** use in new drivers!
1697
See: :ref:`legacy_dvb_decoder_notes`
1699
This ioctl call clears all video buffers in the driver and in the
1700
decoder hardware.
1702
Return Value
1703
~~~~~~~~~~~~
1705
On success 0 is returned, on error -1 and the ``errno`` variable is set
1706
appropriately. The generic error codes are described at the
1707
:ref:`Generic Error Codes <gen-errors>` chapter.
1710
-----
1713
VIDEO_SET_STREAMTYPE
1714
--------------------
1716
Synopsis
1717
~~~~~~~~
1719
.. c:macro:: VIDEO_SET_STREAMTYPE
1721
.. code-block:: c
1723
int ioctl(fd, int request = VIDEO_SET_STREAMTYPE, int type)
1725
Arguments
1726
~~~~~~~~~
1728
.. flat-table::
1729
:header-rows: 0
1730
:stub-columns: 0
1732
- ..
1734
- ``int fd``
1736
- :cspan:`1` File descriptor returned by a previous call
1737
to `open()`_.
1739
- ..
1741
- ``int request``
1743
- Equals ``VIDEO_SET_STREAMTYPE`` for this command.
1745
- ..
1747
- ``int type``
1749
- Stream type.
1751
Description
1752
~~~~~~~~~~~
1754
.. attention:: Do **not** use in new drivers!
1755
See: :ref:`legacy_dvb_decoder_notes`
1757
This ioctl tells the driver which kind of stream to expect being written
1758
to it.
1759
Intelligent decoder might also not support or ignore (like the AV7110)
1760
this call and determine the stream type themselves.
1762
Currently used stream types:
1764
.. flat-table::
1765
:header-rows: 1
1766
:stub-columns: 0
1768
- ..
1770
- Codec
1772
- Stream type
1774
- ..
1776
- MPEG2
1778
- 0
1780
- ..
1782
- MPEG4 h.264
1784
- 1
1786
- ..
1788
- VC1
1790
- 3
1792
- ..
1794
- MPEG4 Part2
1796
- 4
1798
- ..
1800
- VC1 SM
1802
- 5
1804
- ..
1806
- MPEG1
1808
- 6
1810
- ..
1812
- HEVC h.265
1814
- | 7
1815
| DREAMBOX: 22
1817
- ..
1819
- AVS
1821
- 16
1823
- ..
1825
- AVS2
1827
- 40
1829
Not every decoder supports all stream types.
1831
Return Value
1832
~~~~~~~~~~~~
1834
On success 0 is returned, on error -1 and the ``errno`` variable is set
1835
appropriately. The generic error codes are described at the
1836
:ref:`Generic Error Codes <gen-errors>` chapter.
1839
-----
1842
VIDEO_SET_FORMAT
1843
----------------
1845
Synopsis
1846
~~~~~~~~
1848
.. c:macro:: VIDEO_SET_FORMAT
1850
.. code-block:: c
1852
int ioctl(fd, int request = VIDEO_SET_FORMAT, video_format_t format)
1854
Arguments
1855
~~~~~~~~~
1857
.. flat-table::
1858
:header-rows: 0
1859
:stub-columns: 0
1861
- ..
1863
- ``int fd``
1865
- :cspan:`1` File descriptor returned by a previous call
1866
to `open()`_.
1868
- ..
1870
- ``int request``
1872
- Equals ``VIDEO_SET_FORMAT`` for this command.
1874
- ..
1876
- `video_format_t`_ ``format``
1878
- Video format of TV as defined in section `video_format_t`_.
1880
Description
1881
~~~~~~~~~~~
1883
.. attention:: Do **not** use in new drivers!
1884
See: :ref:`legacy_dvb_decoder_notes`
1886
This ioctl sets the screen format (aspect ratio) of the connected output
1887
device (TV) so that the output of the decoder can be adjusted
1888
accordingly.
1890
Return Value
1891
~~~~~~~~~~~~
1893
On success 0 is returned, on error -1 and the ``errno`` variable is set
1894
appropriately. The generic error codes are described at the
1895
:ref:`Generic Error Codes <gen-errors>` chapter.
1898
-----
1901
VIDEO_GET_SIZE
1902
--------------
1904
Synopsis
1905
~~~~~~~~
1907
.. c:macro:: VIDEO_GET_SIZE
1909
.. code-block:: c
1911
int ioctl(int fd, int request = VIDEO_GET_SIZE, video_size_t *size)
1913
Arguments
1914
~~~~~~~~~
1916
.. flat-table::
1917
:header-rows: 0
1918
:stub-columns: 0
1920
- ..
1922
- ``int fd``
1924
- :cspan:`1` File descriptor returned by a previous call,
1925
to `open()`_.
1927
- ..
1929
- ``int request``
1931
- Equals ``VIDEO_GET_SIZE`` for this command.
1933
- ..
1935
- `video_size_t`_ ``*size``
1937
- Returns the size and aspect ratio.
1939
Description
1940
~~~~~~~~~~~
1942
.. attention:: Do **not** use in new drivers!
1943
See: :ref:`legacy_dvb_decoder_notes`
1945
This ioctl returns the size and aspect ratio.
1947
Return Value
1948
~~~~~~~~~~~~
1950
On success 0 is returned, on error -1 and the ``errno`` variable is set
1951
appropriately. The generic error codes are described at the
1952
:ref:`Generic Error Codes <gen-errors>` chapter.
1955
-----
1958
VIDEO_GET_PTS
1959
-------------
1961
Synopsis
1962
~~~~~~~~
1964
.. c:macro:: VIDEO_GET_PTS
1966
.. code-block:: c
1968
int ioctl(int fd, int request = VIDEO_GET_PTS, __u64 *pts)
1970
Arguments
1971
~~~~~~~~~
1973
.. flat-table::
1974
:header-rows: 0
1975
:stub-columns: 0
1977
- ..
1979
- ``int fd``
1981
- :cspan:`1` File descriptor returned by a previous call
1982
to `open()`_.
1984
- ..
1986
- ``int request``
1988
- Equals ``VIDEO_GET_PTS`` for this command.
1990
- ..
1992
- ``__u64 *pts``
1994
- Returns the 33-bit timestamp as defined in ITU T-REC-H.222.0 /
1995
ISO/IEC 13818-1.
1997
The PTS should belong to the currently played frame if possible,
1998
but may also be a value close to it like the PTS of the last
1999
decoded frame or the last PTS extracted by the PES parser.
2001
Description
2002
~~~~~~~~~~~
2004
.. attention:: Do **not** use in new drivers!
2005
See: :ref:`legacy_dvb_decoder_notes`
2007
For V4L2 decoders this ioctl has been replaced by the
2008
``V4L2_CID_MPEG_VIDEO_DEC_PTS`` control.
2010
This ioctl call asks the Video Device to return the current PTS
2011
timestamp.
2013
Return Value
2014
~~~~~~~~~~~~
2016
On success 0 is returned, on error -1 and the ``errno`` variable is set
2017
appropriately. The generic error codes are described at the
2018
:ref:`Generic Error Codes <gen-errors>` chapter.
2021
-----
2024
VIDEO_GET_FRAME_COUNT
2025
---------------------
2027
Synopsis
2028
~~~~~~~~
2030
.. c:macro:: VIDEO_GET_FRAME_COUNT
2032
.. code-block:: c
2034
int ioctl(int fd, VIDEO_GET_FRAME_COUNT, __u64 *pts)
2036
Arguments
2037
~~~~~~~~~
2039
.. flat-table::
2040
:header-rows: 0
2041
:stub-columns: 0
2043
- ..
2045
- ``int fd``
2047
- :cspan:`1` File descriptor returned by a previous call
2048
to `open()`_.
2050
- ..
2052
- ``int request``
2054
- Equals ``VIDEO_GET_FRAME_COUNT`` for this command.
2056
- ..
2058
- ``__u64 *pts``
2060
- Returns the number of frames displayed since the decoder was
2061
started.
2063
Description
2064
~~~~~~~~~~~
2066
.. attention:: Do **not** use in new drivers!
2067
See: :ref:`legacy_dvb_decoder_notes`
2069
For V4L2 decoders this ioctl has been replaced by the
2070
``V4L2_CID_MPEG_VIDEO_DEC_FRAME`` control.
2072
This ioctl call asks the Video Device to return the number of displayed
2073
frames since the decoder was started.
2075
Return Value
2076
~~~~~~~~~~~~
2078
On success 0 is returned, on error -1 and the ``errno`` variable is set
2079
appropriately. The generic error codes are described at the
2080
:ref:`Generic Error Codes <gen-errors>` chapter.
2083
-----
2086
VIDEO_COMMAND
2087
-------------
2089
Synopsis
2090
~~~~~~~~
2092
.. c:macro:: VIDEO_COMMAND
2094
.. code-block:: c
2096
int ioctl(int fd, int request = VIDEO_COMMAND,
2097
struct video_command *cmd)
2099
Arguments
2100
~~~~~~~~~
2102
.. flat-table::
2103
:header-rows: 0
2104
:stub-columns: 0
2106
- ..
2108
- ``int fd``
2110
- :cspan:`1` File descriptor returned by a previous call
2111
to `open()`_.
2113
- ..
2115
- ``int request``
2117
- Equals ``VIDEO_COMMAND`` for this command.
2119
- ..
2121
- `struct video_command`_ ``*cmd``
2123
- Commands the decoder.
2125
Description
2126
~~~~~~~~~~~
2128
.. attention:: Do **not** use in new drivers!
2129
See: :ref:`legacy_dvb_decoder_notes`
2131
For V4L2 decoders this ioctl has been replaced by the
2132
:ref:`VIDIOC_DECODER_CMD` ioctl.
2134
This ioctl commands the decoder. The `struct video_command`_ is a
2135
subset of the ``v4l2_decoder_cmd`` struct, so refer to the
2136
:ref:`VIDIOC_DECODER_CMD` documentation for
2137
more information.
2139
Return Value
2140
~~~~~~~~~~~~
2142
On success 0 is returned, on error -1 and the ``errno`` variable is set
2143
appropriately. The generic error codes are described at the
2144
:ref:`Generic Error Codes <gen-errors>` chapter.
2147
-----
2150
VIDEO_TRY_COMMAND
2151
-----------------
2153
Synopsis
2154
~~~~~~~~
2156
.. c:macro:: VIDEO_TRY_COMMAND
2158
.. code-block:: c
2160
int ioctl(int fd, int request = VIDEO_TRY_COMMAND,
2161
struct video_command *cmd)
2163
Arguments
2164
~~~~~~~~~
2166
.. flat-table::
2167
:header-rows: 0
2168
:stub-columns: 0
2170
- ..
2172
- ``int fd``
2174
- :cspan:`1` File descriptor returned by a previous call
2175
to `open()`_.
2177
- ..
2179
- ``int request``
2181
- Equals ``VIDEO_TRY_COMMAND`` for this command.
2183
- ..
2185
- `struct video_command`_ ``*cmd``
2187
- Try a decoder command.
2189
Description
2190
~~~~~~~~~~~
2192
.. attention:: Do **not** use in new drivers!
2193
See: :ref:`legacy_dvb_decoder_notes`
2195
For V4L2 decoders this ioctl has been replaced by the
2196
:ref:`VIDIOC_TRY_DECODER_CMD <VIDIOC_DECODER_CMD>` ioctl.
2198
This ioctl tries a decoder command. The `struct video_command`_ is a
2199
subset of the ``v4l2_decoder_cmd`` struct, so refer to the
2200
:ref:`VIDIOC_TRY_DECODER_CMD <VIDIOC_DECODER_CMD>` documentation
2201
for more information.
2203
Return Value
2204
~~~~~~~~~~~~
2206
On success 0 is returned, on error -1 and the ``errno`` variable is set
2207
appropriately. The generic error codes are described at the
2208
:ref:`Generic Error Codes <gen-errors>` chapter.
2211
-----
2214
open()
2215
------
2217
Synopsis
2218
~~~~~~~~
2220
.. code-block:: c
2222
#include <fcntl.h>
2224
.. c:function:: int open(const char *deviceName, int flags)
2226
Arguments
2227
~~~~~~~~~
2229
.. flat-table::
2230
:header-rows: 0
2231
:stub-columns: 0
2233
- ..
2235
- ``const char *deviceName``
2237
- Name of specific video device.
2239
- ..
2241
- :rspan:`3` ``int flags``
2243
- :cspan:`1` A bit-wise OR of the following flags:
2245
- ..
2247
- ``O_RDONLY``
2249
- read-only access
2251
- ..
2253
- ``O_RDWR``
2255
- read/write access
2257
- ..
2259
- ``O_NONBLOCK``
2260
- | Open in non-blocking mode
2261
| (blocking mode is the default)
2263
Description
2264
~~~~~~~~~~~
2266
This system call opens a named video device (e.g.
2267
/dev/dvb/adapter?/video?) for subsequent use.
2269
When an open() call has succeeded, the device will be ready for use. The
2270
significance of blocking or non-blocking mode is described in the
2271
documentation for functions where there is a difference. It does not
2272
affect the semantics of the open() call itself. A device opened in
2273
blocking mode can later be put into non-blocking mode (and vice versa)
2274
using the F_SETFL command of the fcntl system call. This is a standard
2275
system call, documented in the Linux manual page for fcntl. Only one
2276
user can open the Video Device in O_RDWR mode. All other attempts to
2277
open the device in this mode will fail, and an error-code will be
2278
returned. If the Video Device is opened in O_RDONLY mode, the only
2279
ioctl call that can be used is `VIDEO_GET_STATUS`_. All other call will
2280
return an error code.
2282
Return Value
2283
~~~~~~~~~~~~
2285
.. flat-table::
2286
:header-rows: 0
2287
:stub-columns: 0
2289
- ..
2291
- ``ENODEV``
2293
- :cspan:`1` Device driver not loaded/available.
2295
- ..
2297
- ``EINTERNAL``
2299
- Internal error.
2301
- ..
2303
- ``EBUSY``
2305
- Device or resource busy.
2307
- ..
2309
- ``EINVAL``
2311
- Invalid argument.
2314
-----
2317
close()
2318
-------
2320
Synopsis
2321
~~~~~~~~
2323
.. c:function:: int close(int fd)
2325
Arguments
2326
~~~~~~~~~
2328
.. flat-table::
2329
:header-rows: 0
2330
:stub-columns: 0
2332
- ..
2334
- ``int fd``
2336
- :cspan:`1` File descriptor returned by a previous call
2337
to `open()`_.
2339
Description
2340
~~~~~~~~~~~
2342
This system call closes a previously opened video device.
2344
Return Value
2345
~~~~~~~~~~~~
2347
.. flat-table::
2348
:header-rows: 0
2349
:stub-columns: 0
2351
- ..
2353
- ``EBADF``
2355
- fd is not a valid open file descriptor.
2358
-----
2361
write()
2362
-------
2364
Synopsis
2365
~~~~~~~~
2367
.. c:function:: size_t write(int fd, const void *buf, size_t count)
2369
Arguments
2370
~~~~~~~~~
2372
.. flat-table::
2373
:header-rows: 0
2374
:stub-columns: 0
2376
- ..
2378
- ``int fd``
2380
- :cspan:`1` File descriptor returned by a previous call
2381
to `open()`_.
2383
- ..
2385
- ``void *buf``
2387
- Pointer to the buffer containing the PES data.
2389
- ..
2391
- ``size_t count``
2393
- Size of buf.
2395
Description
2396
~~~~~~~~~~~
2398
This system call can only be used if VIDEO_SOURCE_MEMORY is selected
2399
in the ioctl call `VIDEO_SELECT_SOURCE`_. The data provided shall be in
2400
PES format, unless the capability allows other formats. TS is the
2401
most common format for storing DVB-data, it is usually supported too.
2402
If O_NONBLOCK is not specified the function will block until buffer space
2403
is available. The amount of data to be transferred is implied by count.
2405
.. note:: See: :ref:`DVB Data Formats <legacy_dvb_decoder_formats>`
2407
Return Value
2408
~~~~~~~~~~~~
2410
.. flat-table::
2411
:header-rows: 0
2412
:stub-columns: 0
2414
- ..
2416
- ``EPERM``
2418
- :cspan:`1` Mode ``VIDEO_SOURCE_MEMORY`` not selected.
2420
- ..
2422
- ``ENOMEM``
2424
- Attempted to write more data than the internal buffer can hold.
2426
- ..
2428
- ``EBADF``
2430
- fd is not a valid open file descriptor.
3. 한국어 전문 번역
영어 원문의 문단 순서와 의미를 유지한 전체 번역입니다. 코드, 함수명, symbol과 URL은 원문 표기를 유지합니다.
MPEG-2 decoder 장치와 V4L2 대체
1-38DVB video device는 DVB 하드웨어의 MPEG-2 video decoder를 제어합니다. `/dev/dvb/adapter0/video0`로 접근하고 응용 프로그램에서 `linux/dvb/video.h`를 포함해 data type과 ioctl 정의를 사용합니다.
이 장치는 MPEG video stream의 decoding만 제어하며 TV나 computer screen에 표시하는 방식은 제어하지 않습니다. PC에서는 보통 `/dev/video` 같은 연결된 Video4Linux 장치가 scaling과 output window를 담당합니다.
대부분의 DVB card에는 자체 MPEG decoder가 없어 audio·video·Video4Linux device node가 생략됩니다. 이 ioctl의 V4L2 decoder 제어 용도도 폐기됐으므로 새 driver는 V4L2 ioctl/control을 사용해야 합니다.
Demux 또는 write()가 MPEG stream 공급→DVB video device가 MPEG stream decoding→연결된 Video4Linux 장치가 scaling과 output window 설정→TV 또는 computer screen에 frame 표시
Decoder 제어와 화면 표시가 분리되는 구조입니다.
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later OR GPL-2.0
.. c:namespace:: dtv.legacy.video
.. _dvb_video:
================
DVB Video Device
================
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
The DVB video device controls the MPEG2 video decoder of the DVB
hardware. It can be accessed through ``/dev/dvb/adapter0/video0``. Data
types and ioctl definitions can be accessed by including
``linux/dvb/video.h`` in your application.
Note that the DVB video device only controls decoding of the MPEG video
stream, not its presentation on the TV or computer screen. On PCs this
is typically handled by an associated video4linux device, e.g.
``/dev/video``, which allows scaling and defining output windows.
Most DVB cards don’t have their own MPEG decoder, which results in the
omission of the audio and video device as well as the video4linux
device.
These ioctls were also used by V4L2 to control MPEG decoders implemented
in V4L2. The use of these ioctls for that purpose has been made obsolete
and proper V4L2 ioctls or controls have been created to replace that
functionality. Use :ref:`V4L2 ioctls<video>` for new drivers!
Video Data Types
================
video_format_t aspect ratio
39-91`video_format_t`는 output hardware의 aspect ratio를 driver에 알리거나 현재 stream의 display format을 보고할 때 사용합니다. `VIDEO_SET_FORMAT`, `video_status`, `video_event`가 이 type을 사용합니다.
상수화면비
VIDEO_FORMAT_4_34:3
VIDEO_FORMAT_16_916:9
VIDEO_FORMAT_221_12.21:1
연결된 display 또는 stream의 화면비입니다.
video_format_t
--------------
Synopsis
~~~~~~~~
.. code-block:: c
typedef enum {
VIDEO_FORMAT_4_3,
VIDEO_FORMAT_16_9,
VIDEO_FORMAT_221_1
} video_format_t;
Constants
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``VIDEO_FORMAT_4_3``
- Select 4:3 format.
- ..
- ``VIDEO_FORMAT_16_9``
- Select 16:9 format.
- ..
- ``VIDEO_FORMAT_221_1``
- Select 2.21:1 format.
Description
~~~~~~~~~~~
The ``video_format_t`` data type
is used in the `VIDEO_SET_FORMAT`_ function to tell the driver which
aspect ratio the output hardware (e.g. TV) has. It is also used in the
data structures `video_status`_ returned by `VIDEO_GET_STATUS`_
and `video_event`_ returned by `VIDEO_GET_EVENT`_ which report
about the display format of the current video stream.
-----
video_displayformat_t cropping mode
92-142Video stream과 display hardware의 화면비가 다르면 응용 프로그램이 picture를 자르는 방식을 `VIDEO_SET_DISPLAY_FORMAT`으로 지정합니다.
상수표시 방식
VIDEO_PAN_SCANPan-and-scan
VIDEO_LETTER_BOXLetterbox
VIDEO_CENTER_CUT_OUTCenter cut-out
서로 다른 화면비를 맞추는 표시 방식입니다.
video_displayformat_t
---------------------
Synopsis
~~~~~~~~
.. code-block:: c
typedef enum {
VIDEO_PAN_SCAN,
VIDEO_LETTER_BOX,
VIDEO_CENTER_CUT_OUT
} video_displayformat_t;
Constants
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``VIDEO_PAN_SCAN``
- Use pan and scan format.
- ..
- ``VIDEO_LETTER_BOX``
- Use letterbox format.
- ..
- ``VIDEO_CENTER_CUT_OUT``
- Use center cut out format.
Description
~~~~~~~~~~~
In case the display format of the video stream and of the display
hardware differ the application has to specify how to handle the
cropping of the picture. This can be done using the
`VIDEO_SET_DISPLAY_FORMAT`_ call which accepts this enum as argument.
-----
video_size_t 해상도
143-191`video_size_t`는 `video_event`에서 video의 해상도와 aspect ratio를 전달합니다.
멤버의미
int wvideo width, pixel 단위
int hvideo height, pixel 단위
video_format_t aspect_ratioaspect ratio
Pixel 크기와 화면비를 함께 저장합니다.
video_size_t
------------
Synopsis
~~~~~~~~
.. code-block:: c
typedef struct {
int w;
int h;
video_format_t aspect_ratio;
} video_size_t;
Variables
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int w``
- Video width in pixels.
- ..
- ``int h``
- Video height in pixels.
- ..
- `video_format_t`_ ``aspect_ratio``
- Aspect ratio.
Description
~~~~~~~~~~~
Used in the struct `video_event`_. It stores the resolution and
aspect ratio of the video.
-----
video_stream_source_t 입력원
192-240`video_stream_source_t`는 `VIDEO_SELECT_SOURCE`가 내부 demux와 응용 프로그램의 `write()` memory source 중 어디에서 stream을 받을지 지정합니다.
상수입력 경로
VIDEO_SOURCE_DEMUXfrontend 또는 DVR에서 공급받는 demultiplexer
VIDEO_SOURCE_MEMORY응용 프로그램이 `write()`로 공급하는 stream
Decoder 입력 경로입니다.
video_stream_source_t
---------------------
Synopsis
~~~~~~~~
.. code-block:: c
typedef enum {
VIDEO_SOURCE_DEMUX,
VIDEO_SOURCE_MEMORY
} video_stream_source_t;
Constants
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``VIDEO_SOURCE_DEMUX``
- :cspan:`1` Select the demux as the main source.
- ..
- ``VIDEO_SOURCE_MEMORY``
- If this source is selected, the stream
comes from the user through the write
system call.
Description
~~~~~~~~~~~
The video stream source is set through the `VIDEO_SELECT_SOURCE`_ call
and can take the following values, depending on whether we are replaying
from an internal (demuxer) or external (user write) source.
VIDEO_SOURCE_DEMUX selects the demultiplexer (fed either by the
frontend or the DVR device) as the source of the video stream. If
VIDEO_SOURCE_MEMORY is selected the stream comes from the application
through the `write()`_ system call.
-----
video_play_state_t 재생 상태
241-289`video_play_state_t`는 `VIDEO_GET_STATUS`가 반환하는 video 재생 상태입니다.
상수상태
VIDEO_STOPPEDVideo 정지
VIDEO_PLAYINGVideo 재생 중
VIDEO_FREEZEDVideo freeze 상태
정지, 재생, freeze 상태입니다.
video_play_state_t
------------------
Synopsis
~~~~~~~~
.. code-block:: c
typedef enum {
VIDEO_STOPPED,
VIDEO_PLAYING,
VIDEO_FREEZED
} video_play_state_t;
Constants
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``VIDEO_STOPPED``
- Video is stopped.
- ..
- ``VIDEO_PLAYING``
- Video is currently playing.
- ..
- ``VIDEO_FREEZED``
- Video is frozen.
Description
~~~~~~~~~~~
This values can be returned by the `VIDEO_GET_STATUS`_ call
representing the state of video playback.
-----
struct video_command
290-390`struct video_command`는 decoder command, flag와 command별 union payload를 담습니다. 미래 확장과 호환되도록 응용 프로그램은 사용 전에 구조체 전체를 0으로 초기화해야 합니다.
멤버/값의미
__u32 cmddecoder command
__u32 flagscommand별 flag
stop.pts정지 command의 MPEG PTS
play.speed = 0 또는 1000normal speed
play.speed = 1 / -1forward / backward single step
play.speed > 1normal speed의 speed/1000 배로 순방향 재생
play.speed < -1normal speed의 -speed/1000 배로 역방향 재생
play.formatplay input format
raw.data[16]향후 확장용 reserved data
stop, play 또는 raw payload 중 하나를 사용합니다.
struct video_command
--------------------
Synopsis
~~~~~~~~
.. code-block:: c
struct video_command {
__u32 cmd;
__u32 flags;
union {
struct {
__u64 pts;
} stop;
struct {
__s32 speed;
__u32 format;
} play;
struct {
__u32 data[16];
} raw;
};
};
Variables
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``__u32 cmd``
- `Decoder command`_
- ..
- ``__u32 flags``
- Flags for the `Decoder command`_.
- ..
- ``struct stop``
- ``__u64 pts``
- MPEG PTS
- ..
- :rspan:`5` ``stuct play``
- :rspan:`4` ``__s32 speed``
- 0 or 1000 specifies normal speed,
- ..
- 1: specifies forward single stepping,
- ..
- -1: specifies backward single stepping,
- ..
- >1: playback at speed / 1000 of the normal speed
- ..
- <-1: reverse playback at ( -speed / 1000 ) of the normal speed.
- ..
- ``__u32 format``
- `Play input formats`_
- ..
- ``__u32 data[16]``
- Reserved
Description
~~~~~~~~~~~
The structure must be zeroed before use by the application. This ensures
it can be extended safely in the future.
-----
Decoder command, flag와 field order
391-517상수동작
VIDEO_CMD_PLAY재생 시작
VIDEO_CMD_STOP재생 정지
VIDEO_CMD_FREEZE재생 freeze
VIDEO_CMD_CONTINUEfreeze 뒤 재생 계속
`video_command.cmd`에 지정하는 기본 동작입니다.
상수의미
VIDEO_CMD_FREEZE_TO_BLACKfreeze 시 검은 화면 표시
VIDEO_CMD_STOP_TO_BLACKstop 시 검은 화면 표시
VIDEO_CMD_STOP_IMMEDIATELYbuffer를 비우지 않고 즉시 stop
VIDEO_PLAY_FMT_NONEdecoder에 특별한 input format 요구가 없음
VIDEO_PLAY_FMT_GOPdecoder가 완전한 GOP를 요구
Freeze·stop 화면 처리와 play data 요구 형식입니다.
상수field
VIDEO_VSYNC_FIELD_UNKNOWNodd, even, progressive 여부를 hardware가 모름
VIDEO_VSYNC_FIELD_ODDodd field
VIDEO_VSYNC_FIELD_EVENeven field
VIDEO_VSYNC_FIELD_PROGRESSIVEprogressive, non-interlaced
Vsync가 어느 field에 해당하는지 나타냅니다.
Predefined decoder commands and flags
-------------------------------------
Synopsis
~~~~~~~~
.. code-block:: c
#define VIDEO_CMD_PLAY (0)
#define VIDEO_CMD_STOP (1)
#define VIDEO_CMD_FREEZE (2)
#define VIDEO_CMD_CONTINUE (3)
#define VIDEO_CMD_FREEZE_TO_BLACK (1 << 0)
#define VIDEO_CMD_STOP_TO_BLACK (1 << 0)
#define VIDEO_CMD_STOP_IMMEDIATELY (1 << 1)
#define VIDEO_PLAY_FMT_NONE (0)
#define VIDEO_PLAY_FMT_GOP (1)
#define VIDEO_VSYNC_FIELD_UNKNOWN (0)
#define VIDEO_VSYNC_FIELD_ODD (1)
#define VIDEO_VSYNC_FIELD_EVEN (2)
#define VIDEO_VSYNC_FIELD_PROGRESSIVE (3)
Constants
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- :rspan:`3` _`Decoder command`
- ``VIDEO_CMD_PLAY``
- Start playback.
- ..
- ``VIDEO_CMD_STOP``
- Stop playback.
- ..
- ``VIDEO_CMD_FREEZE``
- Freeze playback.
- ..
- ``VIDEO_CMD_CONTINUE``
- Continue playback after freeze.
- ..
- Flags for ``VIDEO_CMD_FREEZE``
- ``VIDEO_CMD_FREEZE_TO_BLACK``
- Show black picture on freeze.
- ..
- :rspan:`1` Flags for ``VIDEO_CMD_STOP``
- ``VIDEO_CMD_STOP_TO_BLACK``
- Show black picture on stop.
- ..
- ``VIDEO_CMD_STOP_IMMEDIATELY``
- Stop immediately, without emptying buffers.
- ..
- :rspan:`1` _`Play input formats`
- ``VIDEO_PLAY_FMT_NONE``
- The decoder has no special format requirements
- ..
- ``VIDEO_PLAY_FMT_GOP``
- The decoder requires full GOPs
- ..
- :rspan:`3` Field order
- ``VIDEO_VSYNC_FIELD_UNKNOWN``
- FIELD_UNKNOWN can be used if the hardware does not know
whether the Vsync is for an odd, even or progressive
(i.e. non-interlaced) field.
- ..
- ``VIDEO_VSYNC_FIELD_ODD``
- Vsync is for an odd field.
- ..
- ``VIDEO_VSYNC_FIELD_EVEN``
- Vsync is for an even field.
- ..
- ``VIDEO_VSYNC_FIELD_PROGRESSIVE``
- progressive (i.e. non-interlaced)
-----
video_event 비동기 event
518-613`VIDEO_GET_EVENT`는 `video_event` 구조체로 크기, frame rate, decoder 정지, Vsync event를 반환합니다.
멤버/상수의미
VIDEO_EVENT_SIZE_CHANGED해상도 또는 aspect ratio 변경, `u.size` 사용
VIDEO_EVENT_FRAME_RATE_CHANGEDframe rate 변경, `u.frame_rate` 사용
VIDEO_EVENT_DECODER_STOPPEDdecoder 정지
VIDEO_EVENT_VSYNCVsync 발생, `u.vsync_field` 사용
long timestampevent 발생 시 MPEG PTS
video_size_t sizevideo 해상도와 aspect ratio
unsigned int frame_rate원문 표현으로 frames per 1000sec
unsigned char vsync_fieldunknown, odd, even 또는 progressive
Event 발생 시각은 MPEG PTS로 기록합니다.
video_event
-----------
Synopsis
~~~~~~~~
.. code-block:: c
struct video_event {
__s32 type;
#define VIDEO_EVENT_SIZE_CHANGED 1
#define VIDEO_EVENT_FRAME_RATE_CHANGED 2
#define VIDEO_EVENT_DECODER_STOPPED 3
#define VIDEO_EVENT_VSYNC 4
long timestamp;
union {
video_size_t size;
unsigned int frame_rate;
unsigned char vsync_field;
} u;
};
Variables
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- :rspan:`4` ``__s32 type``
- :cspan:`1` Event type.
- ..
- ``VIDEO_EVENT_SIZE_CHANGED``
- Size changed.
- ..
- ``VIDEO_EVENT_FRAME_RATE_CHANGED``
- Framerate changed.
- ..
- ``VIDEO_EVENT_DECODER_STOPPED``
- Decoder stopped.
- ..
- ``VIDEO_EVENT_VSYNC``
- Vsync occurred.
- ..
- ``long timestamp``
- :cspan:`1` MPEG PTS at occurrence.
- ..
- :rspan:`2` ``union u``
- `video_size_t`_ size
- Resolution and aspect ratio of the video.
- ..
- ``unsigned int frame_rate``
- in frames per 1000sec
- ..
- ``unsigned char vsync_field``
- | unknown / odd / even / progressive
| See: `Predefined decoder commands and flags`_
Description
~~~~~~~~~~~
This is the structure of a video event as it is returned by the
`VIDEO_GET_EVENT`_ call. See there for more details.
-----
video_status 종합 상태
614-699`VIDEO_GET_STATUS`는 blank 방식, 재생 상태, 입력원, stream aspect ratio, cropping mode를 `video_status`로 반환합니다.
멤버/값의미
video_blank != 0channel 변경 또는 stop/freeze 시 blank screen
video_blank == 0마지막으로 decode한 frame 표시
video_play_state_t play_statefrozen, stopped 또는 playing
video_stream_source_t stream_sourcedemux 또는 memory
video_format_t video_format현재 stream의 aspect ratio
video_displayformat_t display_formatoutput 화면비와 다를 때 적용한 cropping mode
현재 playback 동작과 화면 처리 상태입니다.
video_status
------------
Synopsis
~~~~~~~~
The `VIDEO_GET_STATUS`_ call returns the following structure informing
about various states of the playback operation.
.. code-block:: c
struct video_status {
int video_blank;
video_play_state_t play_state;
video_stream_source_t stream_source;
video_format_t video_format;
video_displayformat_t display_format;
};
Variables
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- :rspan:`2` ``int video_blank``
- :cspan:`1` Show blank video on freeze?
- ..
- TRUE ( != 0 )
- Blank screen when freeze.
- ..
- FALSE ( == 0 )
- Show last decoded frame.
- ..
- `video_play_state_t`_ ``play_state``
- Current state of playback.
- ..
- `video_stream_source_t`_ ``stream_source``
- Current source (demux/memory).
- ..
- `video_format_t`_ ``video_format``
- Current aspect ratio of stream.
- ..
- `video_displayformat_t`_ ``display_format``
- Applied cropping mode.
Description
~~~~~~~~~~~
If ``video_blank`` is set ``TRUE`` video will be blanked out if the
channel is changed or if playback is stopped. Otherwise, the last picture
will be displayed. ``play_state`` indicates if the video is currently
frozen, stopped, or being played back. The ``stream_source`` corresponds
to the selected source for the video stream. It can come either from the
demultiplexer or from memory. The ``video_format`` indicates the aspect
ratio (one of 4:3 or 16:9) of the currently played video stream.
Finally, ``display_format`` corresponds to the applied cropping mode in
case the source video format is not the same as the format of the output
device.
-----
video_still_picture I-frame
700-742`video_still_picture`는 `VIDEO_STILLPICTURE`가 표시할 단일 I-frame의 memory pointer와 크기를 전달합니다.
멤버의미
char *iFramememory의 단일 I-frame pointer
int32_t sizeI-frame byte 크기
Elementary stream에서 추출한 I-frame을 가리킵니다.
video_still_picture
-------------------
Synopsis
~~~~~~~~
.. code-block:: c
struct video_still_picture {
char *iFrame;
int32_t size;
};
Variables
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``char *iFrame``
- Pointer to a single iframe in memory.
- ..
- ``int32_t size``
- Size of the iframe.
Description
~~~~~~~~~~~
An I-frame displayed via the `VIDEO_STILLPICTURE`_ call is passed on
within this structure.
-----
Video capability bit
743-803`VIDEO_GET_CAPABILITIES`는 hardware가 지원하는 codec과 stream container를 unsigned integer bit mask로 반환합니다.
Bitcapability
VIDEO_CAP_MPEG1hardware가 MPEG-1 decoding 지원
VIDEO_CAP_MPEG2hardware가 MPEG-2 decoding 지원
VIDEO_CAP_SYSvideo device가 system stream 수용
VIDEO_CAP_PROGvideo device가 program stream 수용
System/program stream은 audio와 video device를 모두 열되 stream은 video device에만 보냅니다.
video capabilities
------------------
Synopsis
~~~~~~~~
.. code-block:: c
#define VIDEO_CAP_MPEG1 1
#define VIDEO_CAP_MPEG2 2
#define VIDEO_CAP_SYS 4
#define VIDEO_CAP_PROG 8
Constants
~~~~~~~~~
Bit definitions for capabilities:
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``VIDEO_CAP_MPEG1``
- :cspan:`1` The hardware can decode MPEG1.
- ..
- ``VIDEO_CAP_MPEG2``
- The hardware can decode MPEG2.
- ..
- ``VIDEO_CAP_SYS``
- The video device accepts system stream.
You still have to open the video and the audio device
but only send the stream to the video device.
- ..
- ``VIDEO_CAP_PROG``
- The video device accepts program stream.
You still have to open the video and the audio device
but only send the stream to the video device.
Description
~~~~~~~~~~~
A call to `VIDEO_GET_CAPABILITIES`_ returns an unsigned integer with the
following bits set according to the hardware's capabilities.
-----
VIDEO_STOP
804-881`VIDEO_STOP`은 현재 stream 재생을 정지하고 `mode`에 따라 화면을 blank 처리하거나 마지막 decoded frame을 유지합니다. V4L2 decoder는 `VIDIOC_DECODER_CMD`를 사용합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_STOP`
mode != 0stop 시 blank screen
mode == 0마지막 decoded frame 표시
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
Video Function Calls
====================
VIDEO_STOP
----------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_STOP
.. code-block:: c
int ioctl(fd, VIDEO_STOP, int mode)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- :cspan:`1` Equals ``VIDEO_STOP`` for this command.
- ..
- :rspan:`2` ``int mode``
- :cspan:`1` Indicates how the screen shall be handled.
- ..
- TRUE ( != 0 )
- Blank screen when stop.
- ..
- FALSE ( == 0 )
- Show last decoded frame.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl is for Digital TV devices only. To control a V4L2 decoder use
the V4L2 :ref:`VIDIOC_DECODER_CMD` instead.
This ioctl call asks the Video Device to stop playing the current
stream. Depending on the input parameter, the screen can be blanked out
or displaying the last decoded frame.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_PLAY
882-936`VIDEO_PLAY`는 선택한 source의 video stream 재생을 시작합니다. V4L2 decoder는 `VIDIOC_DECODER_CMD`를 사용합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_PLAY`
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_PLAY
----------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_PLAY
.. code-block:: c
int ioctl(fd, VIDEO_PLAY)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_PLAY`` for this command.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl is for Digital TV devices only. To control a V4L2 decoder use
the V4L2 :ref:`VIDIOC_DECODER_CMD` instead.
This ioctl call asks the Video Device to start playing a video stream
from the selected source.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_FREEZE
937-996`VIDEO_FREEZE`는 재생 중인 live video를 freeze합니다. `VIDEO_SOURCE_DEMUX`에서는 decoding과 재생을 멈추고, `VIDEO_SOURCE_MEMORY`에서는 `VIDEO_CONTINUE` 또는 `VIDEO_PLAY`까지 더 이상 data를 decode하지 않습니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_FREEZE`
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_FREEZE
------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_FREEZE
.. code-block:: c
int ioctl(fd, VIDEO_FREEZE)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_FREEZE`` for this command.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl is for Digital TV devices only. To control a V4L2 decoder use
the V4L2 :ref:`VIDIOC_DECODER_CMD` instead.
This ioctl call suspends the live video stream being played, if
VIDEO_SOURCE_DEMUX is selected. Decoding and playing are frozen.
It is then possible to restart the decoding and playing process of the
video stream using the `VIDEO_CONTINUE`_ command.
If VIDEO_SOURCE_MEMORY is selected in the ioctl call
`VIDEO_SELECT_SOURCE`_, the Digital TV subsystem will not decode any more
data until the ioctl call `VIDEO_CONTINUE`_ or `VIDEO_PLAY`_ is performed.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_CONTINUE
997-1051`VIDEO_CONTINUE`는 `VIDEO_FREEZE` 전의 video stream decoding과 재생을 다시 시작합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_CONTINUE`
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_CONTINUE
--------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_CONTINUE
.. code-block:: c
int ioctl(fd, VIDEO_CONTINUE)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_CONTINUE`` for this command.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl is for Digital TV devices only. To control a V4L2 decoder use
the V4L2 :ref:`VIDIOC_DECODER_CMD` instead.
This ioctl call restarts decoding and playing processes of the video
stream which was played before a call to `VIDEO_FREEZE`_ was made.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_SELECT_SOURCE
1052-1120`VIDEO_SELECT_SOURCE`는 input data를 demux 또는 응용 프로그램 memory에서 받을지 지정합니다. ivtv의 V4L2 지원은 `IVTV_IOC_PASSTHROUGH_MODE`로 대체됐습니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_SELECT_SOURCE`
video_stream_source_t source`VIDEO_SOURCE_DEMUX` 또는 `VIDEO_SOURCE_MEMORY`
호출에 전달하거나 호출에서 돌려받는 값입니다.
Memory source는 `write()`로 공급하고 demux source는 onboard demux가 decoder로 직접 보냅니다. Decoder data는 PID filter의 제어도 받으며 demux output은 `DMX_OUT_DECODER`를 선택합니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_SELECT_SOURCE
-------------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_SELECT_SOURCE
.. code-block:: c
int ioctl(fd, VIDEO_SELECT_SOURCE, video_stream_source_t source)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_SELECT_SOURCE`` for this command.
- ..
- `video_stream_source_t`_ ``source``
- Indicates which source shall be used for the Video stream.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl is for Digital TV devices only. This ioctl was also supported
by the V4L2 ivtv driver, but that has been replaced by the ivtv-specific
``IVTV_IOC_PASSTHROUGH_MODE`` ioctl.
This ioctl call informs the video device which source shall be used for
the input data. The possible sources are demux or memory. If memory is
selected, the data is fed to the video device through the write command
using the struct `video_stream_source_t`_. If demux is selected, the data
is directly transferred from the onboard demux-device to the decoder.
The data fed to the decoder is also controlled by the PID-filter.
Output selection: :c:type:`dmx_output` ``DMX_OUT_DECODER``.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_SET_BLANK
1121-1189`VIDEO_SET_BLANK`는 picture를 blank 처리할지 정합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_SET_BLANK`
mode != 0stop 시 blank screen
mode == 0마지막 decoded frame 표시
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_SET_BLANK
---------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_SET_BLANK
.. code-block:: c
int ioctl(fd, VIDEO_SET_BLANK, int mode)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- :cspan:`1` Equals ``VIDEO_SET_BLANK`` for this command.
- ..
- :rspan:`2` ``int mode``
- :cspan:`1` Indicates if the screen shall be blanked.
- ..
- TRUE ( != 0 )
- Blank screen when stop.
- ..
- FALSE ( == 0 )
- Show last decoded frame.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl call asks the Video Device to blank out the picture.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_GET_STATUS
1190-1248`VIDEO_GET_STATUS`는 Video Device의 현재 상태를 `struct video_status`에 채워 반환합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_GET_STATUS`
struct video_status *status현재 상태를 받을 구조체 pointer
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_GET_STATUS
----------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_GET_STATUS
.. code-block:: c
int ioctl(fd, int request = VIDEO_GET_STATUS,
struct video_status *status)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_GET_STATUS`` for this command.
- ..
- ``struct`` `video_status`_ ``*status``
- Returns the current status of the Video Device.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl call asks the Video Device to return the current status of
the device.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_GET_EVENT
1249-1337`VIDEO_GET_EVENT`는 대기 중인 `video_event`를 발생 순서대로 반환합니다. 제한된 최신 event만 queue에 남으므로 늦게 가져오면 오래된 event가 폐기될 수 있습니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_GET_EVENT`
struct video_event *evevent를 저장할 구조체 pointer
호출에 전달하거나 호출에서 돌려받는 값입니다.
조건동작
blocking modeevent가 생길 때까지 block
non-blocking modeevent가 없으면 즉시 `EWOULDBLOCK`
select()fd를 `exceptfds`에 포함
poll()wake-up condition으로 `POLLPRI` 지정
EOVERFLOWevent queue overflow로 하나 이상 유실
Blocking mode와 event queue 상태에 따른 동작입니다.
Read-only 권한으로도 호출할 수 있습니다. V4L2 decoder는 `VIDIOC_DQEVENT`를 사용합니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_GET_EVENT
---------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_GET_EVENT
.. code-block:: c
int ioctl(fd, int request = VIDEO_GET_EVENT,
struct video_event *ev)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_GET_EVENT`` for this command.
- ..
- ``struct`` `video_event`_ ``*ev``
- Points to the location where the event, if any, is to be stored.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl is for DVB devices only. To get events from a V4L2 decoder
use the V4L2 :ref:`VIDIOC_DQEVENT` ioctl instead.
This ioctl call returns an event of type `video_event`_ if available. A
certain number of the latest events will be cued and returned in order of
occurrence. Older events may be discarded if not fetched in time. If
an event is not available, the behavior depends on whether the device is
in blocking or non-blocking mode. In the latter case, the call fails
immediately with errno set to ``EWOULDBLOCK``. In the former case, the
call blocks until an event becomes available. The standard Linux poll()
and/or select() system calls can be used with the device file descriptor
to watch for new events. For select(), the file descriptor should be
included in the exceptfds argument, and for poll(), POLLPRI should be
specified as the wake-up condition. Read-only permissions are sufficient
for this ioctl call.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``EWOULDBLOCK``
- :cspan:`1` There is no event pending, and the device is in
non-blocking mode.
- ..
- ``EOVERFLOW``
- Overflow in event queue - one or more events were lost.
-----
VIDEO_SET_DISPLAY_FORMAT
1338-1396`VIDEO_SET_DISPLAY_FORMAT`은 MPEG chip이 video에 적용할 pan-scan, letterbox 또는 center cut-out 형식을 선택합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_SET_DISPLAY_FORMAT`
video_displayformat_t format적용할 cropping/display mode
호출에 전달하거나 호출에서 돌려받는 값입니다.
원문 synopsis는 `video_display_format_t`라고 적지만 앞에서 정의한 type과 인자 표는 `video_displayformat_t`입니다. 원문 표기는 수정하지 않고 차이를 표시했습니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_SET_DISPLAY_FORMAT
------------------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_SET_DISPLAY_FORMAT
.. code-block:: c
int ioctl(fd, int request = VIDEO_SET_DISPLAY_FORMAT,
video_display_format_t format)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_SET_DISPLAY_FORMAT`` for this command.
- ..
- `video_displayformat_t`_ ``format``
- Selects the video format to be used.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl call asks the Video Device to select the video format to be
applied by the MPEG chip on the video.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_STILLPICTURE
1397-1463`VIDEO_STILLPICTURE`는 elementary video stream의 I-frame 하나를 still picture로 표시합니다. 보통 TS 또는 PES recording에서 해당 구간을 추출하며, device가 resolution과 codec을 지원해야 합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_STILLPICTURE`
struct video_still_picture *spI-frame pointer와 size를 담은 구조체
호출에 전달하거나 호출에서 돌려받는 값입니다.
Pointer가 NULL이면 현재 still picture를 blank 처리합니다. AV7110은 일반적인 PAL-SD 해상도의 MPEG-1과 MPEG-2를 지원합니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_STILLPICTURE
------------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_STILLPICTURE
.. code-block:: c
int ioctl(fd, int request = VIDEO_STILLPICTURE,
struct video_still_picture *sp)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_STILLPICTURE`` for this command.
- ..
- ``struct`` `video_still_picture`_ ``*sp``
- Pointer to the location where the struct with the I-frame
and size is stored.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl call asks the Video Device to display a still picture
(I-frame). The input data shall be the section of an elementary video
stream containing an I-frame. Typically this section is extracted from a
TS or PES recording. Resolution and codec (see `video capabilities`_) must
be supported by the device. If the pointer is NULL, then the current
displayed still picture is blanked.
e.g. The AV7110 supports MPEG1 and MPEG2 with the common PAL-SD
resolutions.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_FAST_FORWARD
1464-1532`VIDEO_FAST_FORWARD`는 N개의 I-frame decoding을 건너뜁니다. `VIDEO_SOURCE_MEMORY`를 선택한 경우에만 사용할 수 있습니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_FAST_FORWARD`
int nFrames건너뛸 I-frame 수
호출에 전달하거나 호출에서 돌려받는 값입니다.
오류의미
EPERM`VIDEO_SOURCE_MEMORY`를 선택하지 않음
입력 source 제약입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_FAST_FORWARD
------------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_FAST_FORWARD
.. code-block:: c
int ioctl(fd, int request = VIDEO_FAST_FORWARD, int nFrames)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_FAST_FORWARD`` for this command.
- ..
- ``int nFrames``
- The number of frames to skip.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl call asks the Video Device to skip decoding of N number of
I-frames. This call can only be used if ``VIDEO_SOURCE_MEMORY`` is
selected.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``EPERM``
- Mode ``VIDEO_SOURCE_MEMORY`` not selected.
-----
VIDEO_SLOWMOTION
1533-1601`VIDEO_SLOWMOTION`은 각 frame을 N번 반복 decode해 slow motion을 구현합니다. `VIDEO_SOURCE_MEMORY`를 선택한 경우에만 사용할 수 있습니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_SLOWMOTION`
int nFrames각 frame을 반복할 횟수
호출에 전달하거나 호출에서 돌려받는 값입니다.
오류의미
EPERM`VIDEO_SOURCE_MEMORY`를 선택하지 않음
입력 source 제약입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_SLOWMOTION
----------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_SLOWMOTION
.. code-block:: c
int ioctl(fd, int request = VIDEO_SLOWMOTION, int nFrames)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_SLOWMOTION`` for this command.
- ..
- ``int nFrames``
- The number of times to repeat each frame.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl call asks the video device to repeat decoding frames N number
of times. This call can only be used if ``VIDEO_SOURCE_MEMORY`` is
selected.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``EPERM``
- Mode ``VIDEO_SOURCE_MEMORY`` not selected.
-----
VIDEO_GET_CAPABILITIES
1602-1660`VIDEO_GET_CAPABILITIES`는 video hardware의 decoding capability bit mask를 조회합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_GET_CAPABILITIES`
unsigned int *capcapability bit mask를 받을 pointer
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_GET_CAPABILITIES
----------------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_GET_CAPABILITIES
.. code-block:: c
int ioctl(fd, int request = VIDEO_GET_CAPABILITIES, unsigned int *cap)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_GET_CAPABILITIES`` for this command.
- ..
- ``unsigned int *cap``
- Pointer to a location where to store the capability information.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl call asks the video device about its decoding capabilities.
On success it returns an integer which has bits set according to the
defines in `video capabilities`_.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_CLEAR_BUFFER
1661-1712`VIDEO_CLEAR_BUFFER`는 driver와 decoder hardware의 모든 video buffer를 비웁니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_CLEAR_BUFFER`
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_CLEAR_BUFFER
------------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_CLEAR_BUFFER
.. code-block:: c
int ioctl(fd, int request = VIDEO_CLEAR_BUFFER)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_CLEAR_BUFFER`` for this command.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl call clears all video buffers in the driver and in the
decoder hardware.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_SET_STREAMTYPE
1713-1841`VIDEO_SET_STREAMTYPE`은 `write()`로 들어올 stream codec type을 driver에 알립니다. AV7110 같은 지능형 decoder는 이 호출을 지원하지 않거나 무시하고 stream type을 스스로 판별할 수 있습니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_SET_STREAMTYPE`
int type예상할 stream type 번호
호출에 전달하거나 호출에서 돌려받는 값입니다.
Codecstream type
MPEG-20
MPEG-4 H.2641
VC-13
MPEG-4 Part 24
VC-1 Simple/Main5
MPEG-16
HEVC H.2657, DREAMBOX에서는 22
AVS16
AVS240
모든 decoder가 모든 codec을 지원하는 것은 아닙니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_SET_STREAMTYPE
--------------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_SET_STREAMTYPE
.. code-block:: c
int ioctl(fd, int request = VIDEO_SET_STREAMTYPE, int type)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_SET_STREAMTYPE`` for this command.
- ..
- ``int type``
- Stream type.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl tells the driver which kind of stream to expect being written
to it.
Intelligent decoder might also not support or ignore (like the AV7110)
this call and determine the stream type themselves.
Currently used stream types:
.. flat-table::
:header-rows: 1
:stub-columns: 0
- ..
- Codec
- Stream type
- ..
- MPEG2
- 0
- ..
- MPEG4 h.264
- 1
- ..
- VC1
- 3
- ..
- MPEG4 Part2
- 4
- ..
- VC1 SM
- 5
- ..
- MPEG1
- 6
- ..
- HEVC h.265
- | 7
| DREAMBOX: 22
- ..
- AVS
- 16
- ..
- AVS2
- 40
Not every decoder supports all stream types.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_SET_FORMAT
1842-1900`VIDEO_SET_FORMAT`은 연결된 output device, 예를 들어 TV의 screen aspect ratio를 설정해 decoder output을 맞춥니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_SET_FORMAT`
video_format_t formatoutput TV의 4:3, 16:9 또는 2.21:1 format
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_SET_FORMAT
----------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_SET_FORMAT
.. code-block:: c
int ioctl(fd, int request = VIDEO_SET_FORMAT, video_format_t format)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_SET_FORMAT`` for this command.
- ..
- `video_format_t`_ ``format``
- Video format of TV as defined in section `video_format_t`_.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl sets the screen format (aspect ratio) of the connected output
device (TV) so that the output of the decoder can be adjusted
accordingly.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_GET_SIZE
1901-1957`VIDEO_GET_SIZE`는 현재 video의 pixel size와 aspect ratio를 `video_size_t`로 반환합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_GET_SIZE`
video_size_t *sizewidth, height, aspect ratio를 받을 pointer
호출에 전달하거나 호출에서 돌려받는 값입니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_GET_SIZE
--------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_GET_SIZE
.. code-block:: c
int ioctl(int fd, int request = VIDEO_GET_SIZE, video_size_t *size)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call,
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_GET_SIZE`` for this command.
- ..
- `video_size_t`_ ``*size``
- Returns the size and aspect ratio.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
This ioctl returns the size and aspect ratio.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_GET_PTS
1958-2023`VIDEO_GET_PTS`는 ITU T-REC-H.222.0 / ISO/IEC 13818-1에 정의된 현재 33-bit PTS를 반환합니다. 가능하면 현재 frame의 PTS지만 마지막 decoded frame 또는 PES parser가 마지막으로 추출한 가까운 값일 수 있습니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_GET_PTS`
__u64 *pts33-bit PTS를 받을 pointer
호출에 전달하거나 호출에서 돌려받는 값입니다.
V4L2 decoder에서는 `V4L2_CID_MPEG_VIDEO_DEC_PTS` control로 대체됐습니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_GET_PTS
-------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_GET_PTS
.. code-block:: c
int ioctl(int fd, int request = VIDEO_GET_PTS, __u64 *pts)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_GET_PTS`` for this command.
- ..
- ``__u64 *pts``
- Returns the 33-bit timestamp as defined in ITU T-REC-H.222.0 /
ISO/IEC 13818-1.
The PTS should belong to the currently played frame if possible,
but may also be a value close to it like the PTS of the last
decoded frame or the last PTS extracted by the PES parser.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
For V4L2 decoders this ioctl has been replaced by the
``V4L2_CID_MPEG_VIDEO_DEC_PTS`` control.
This ioctl call asks the Video Device to return the current PTS
timestamp.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_GET_FRAME_COUNT
2024-2085`VIDEO_GET_FRAME_COUNT`는 decoder 시작 뒤 표시한 frame 수를 반환합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_GET_FRAME_COUNT`
__u64 *pts표시한 frame 수를 받을 pointer
호출에 전달하거나 호출에서 돌려받는 값입니다.
원문은 결과 pointer 이름을 `pts`라고 적지만 의미는 PTS가 아니라 frame count입니다. V4L2에서는 `V4L2_CID_MPEG_VIDEO_DEC_FRAME` control로 대체됐습니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_GET_FRAME_COUNT
---------------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_GET_FRAME_COUNT
.. code-block:: c
int ioctl(int fd, VIDEO_GET_FRAME_COUNT, __u64 *pts)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_GET_FRAME_COUNT`` for this command.
- ..
- ``__u64 *pts``
- Returns the number of frames displayed since the decoder was
started.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
For V4L2 decoders this ioctl has been replaced by the
``V4L2_CID_MPEG_VIDEO_DEC_FRAME`` control.
This ioctl call asks the Video Device to return the number of displayed
frames since the decoder was started.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_COMMAND
2086-2149`VIDEO_COMMAND`는 `struct video_command`로 decoder에 play, stop, freeze 또는 continue command를 실행합니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_COMMAND`
struct video_command *cmd실행할 decoder command 구조체
호출에 전달하거나 호출에서 돌려받는 값입니다.
이 구조체는 `v4l2_decoder_cmd`의 부분집합입니다. V4L2 decoder는 `VIDIOC_DECODER_CMD`를 사용합니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_COMMAND
-------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_COMMAND
.. code-block:: c
int ioctl(int fd, int request = VIDEO_COMMAND,
struct video_command *cmd)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_COMMAND`` for this command.
- ..
- `struct video_command`_ ``*cmd``
- Commands the decoder.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
For V4L2 decoders this ioctl has been replaced by the
:ref:`VIDIOC_DECODER_CMD` ioctl.
This ioctl commands the decoder. The `struct video_command`_ is a
subset of the ``v4l2_decoder_cmd`` struct, so refer to the
:ref:`VIDIOC_DECODER_CMD` documentation for
more information.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
VIDEO_TRY_COMMAND
2150-2213`VIDEO_TRY_COMMAND`는 `struct video_command`가 지원 가능한지 시험합니다. 실제 실행 전 command를 검증하는 경로입니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
int request이 명령에서는 `VIDEO_TRY_COMMAND`
struct video_command *cmd시험할 decoder command 구조체
호출에 전달하거나 호출에서 돌려받는 값입니다.
이 구조체는 `v4l2_decoder_cmd`의 부분집합이며 V4L2에서는 `VIDIOC_TRY_DECODER_CMD`를 사용합니다.
주의: 이 ioctl은 새 드라이버에서 사용하면 안 됩니다. 새 V4L2 decoder는 대응하는 V4L2 ioctl 또는 control을 사용해야 합니다.
성공하면 0을 반환합니다. 오류이면 -1을 반환하고 `errno`를 설정하며, 공통 오류 의미는 Generic Error Codes 절을 따릅니다.
VIDEO_TRY_COMMAND
-----------------
Synopsis
~~~~~~~~
.. c:macro:: VIDEO_TRY_COMMAND
.. code-block:: c
int ioctl(int fd, int request = VIDEO_TRY_COMMAND,
struct video_command *cmd)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``int request``
- Equals ``VIDEO_TRY_COMMAND`` for this command.
- ..
- `struct video_command`_ ``*cmd``
- Try a decoder command.
Description
~~~~~~~~~~~
.. attention:: Do **not** use in new drivers!
See: :ref:`legacy_dvb_decoder_notes`
For V4L2 decoders this ioctl has been replaced by the
:ref:`VIDIOC_TRY_DECODER_CMD <VIDIOC_DECODER_CMD>` ioctl.
This ioctl tries a decoder command. The `struct video_command`_ is a
subset of the ``v4l2_decoder_cmd`` struct, so refer to the
:ref:`VIDIOC_TRY_DECODER_CMD <VIDIOC_DECODER_CMD>` documentation
for more information.
Return Value
~~~~~~~~~~~~
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
-----
open() video 장치 열기
2214-2316`open()`은 `/dev/dvb/adapter?/video?` 장치를 열어 이후 호출에 사용할 file descriptor를 얻습니다. Blocking mode는 나중에 `fcntl(F_SETFL)`로 바꿀 수 있습니다.
인자/flag의미
const char *deviceName열 video device 이름
O_RDONLY읽기 전용 접근
O_RDWR읽기/쓰기 접근
O_NONBLOCKnon-blocking mode, 기본값은 blocking
`flags`는 access와 non-blocking flag를 bitwise OR로 조합합니다.
`O_RDWR`는 한 사용자만 열 수 있습니다. `O_RDONLY`로 열면 `VIDEO_GET_STATUS`만 사용할 수 있고 다른 ioctl은 오류를 반환합니다.
오류의미
ENODEVdriver가 load되지 않았거나 사용할 수 없음
EINTERNAL내부 오류
EBUSYdevice 또는 resource가 사용 중
EINVAL잘못된 인자
대표 오류 code입니다.
open()
------
Synopsis
~~~~~~~~
.. code-block:: c
#include <fcntl.h>
.. c:function:: int open(const char *deviceName, int flags)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``const char *deviceName``
- Name of specific video device.
- ..
- :rspan:`3` ``int flags``
- :cspan:`1` A bit-wise OR of the following flags:
- ..
- ``O_RDONLY``
- read-only access
- ..
- ``O_RDWR``
- read/write access
- ..
- ``O_NONBLOCK``
- | Open in non-blocking mode
| (blocking mode is the default)
Description
~~~~~~~~~~~
This system call opens a named video device (e.g.
/dev/dvb/adapter?/video?) for subsequent use.
When an open() call has succeeded, the device will be ready for use. The
significance of blocking or non-blocking mode is described in the
documentation for functions where there is a difference. It does not
affect the semantics of the open() call itself. A device opened in
blocking mode can later be put into non-blocking mode (and vice versa)
using the F_SETFL command of the fcntl system call. This is a standard
system call, documented in the Linux manual page for fcntl. Only one
user can open the Video Device in O_RDWR mode. All other attempts to
open the device in this mode will fail, and an error-code will be
returned. If the Video Device is opened in O_RDONLY mode, the only
ioctl call that can be used is `VIDEO_GET_STATUS`_. All other call will
return an error code.
Return Value
~~~~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``ENODEV``
- :cspan:`1` Device driver not loaded/available.
- ..
- ``EINTERNAL``
- Internal error.
- ..
- ``EBUSY``
- Device or resource busy.
- ..
- ``EINVAL``
- Invalid argument.
-----
close() video 장치 닫기
2317-2360`close(fd)`는 이전에 연 video device를 닫습니다.
인자/오류설명
int fd이전 `open()`에서 받은 file descriptor
EBADFfd가 유효한 열린 file descriptor가 아님
유효한 열린 file descriptor를 전달해야 합니다.
close()
-------
Synopsis
~~~~~~~~
.. c:function:: int close(int fd)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
Description
~~~~~~~~~~~
This system call closes a previously opened video device.
Return Value
~~~~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``EBADF``
- fd is not a valid open file descriptor.
-----
write() video stream 공급
2361-2430`write(fd, buf, count)`는 `VIDEO_SELECT_SOURCE`에서 `VIDEO_SOURCE_MEMORY`를 선택했을 때만 사용할 수 있습니다. 기본 data는 PES format이며 capability가 허용하면 다른 형식도 가능하고, DVB recording에 흔한 TS도 보통 지원됩니다.
인자설명
int fd이전 `open()`에서 받은 file descriptor
const void *bufPES 또는 지원 stream data buffer
size_t count전송할 byte 수
사용자 공간 buffer의 stream을 decoder에 전달합니다.
`O_NONBLOCK`을 지정하지 않으면 buffer 공간이 생길 때까지 block됩니다. 지원 형식은 DVB Data Formats와 capability를 함께 확인해야 합니다.
오류의미
EPERM`VIDEO_SOURCE_MEMORY`를 선택하지 않음
ENOMEM내부 buffer 용량보다 많은 data를 쓰려고 함
EBADFfd가 유효한 열린 file descriptor가 아님
Source mode, buffer 용량, descriptor 상태에 따른 오류입니다.
VIDEO_SELECT_SOURCE로 VIDEO_SOURCE_MEMORY 선택→지원 codec·container와 VIDEO_SET_STREAMTYPE 확인→PES 또는 지원되는 TS data를 buffer에 준비→write(fd, buf, count) 호출→VIDEO_PLAY 또는 VIDEO_COMMAND로 재생 제어
응용 프로그램 stream이 decoder로 들어가는 순서입니다.
write()
-------
Synopsis
~~~~~~~~
.. c:function:: size_t write(int fd, const void *buf, size_t count)
Arguments
~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``int fd``
- :cspan:`1` File descriptor returned by a previous call
to `open()`_.
- ..
- ``void *buf``
- Pointer to the buffer containing the PES data.
- ..
- ``size_t count``
- Size of buf.
Description
~~~~~~~~~~~
This system call can only be used if VIDEO_SOURCE_MEMORY is selected
in the ioctl call `VIDEO_SELECT_SOURCE`_. The data provided shall be in
PES format, unless the capability allows other formats. TS is the
most common format for storing DVB-data, it is usually supported too.
If O_NONBLOCK is not specified the function will block until buffer space
is available. The amount of data to be transferred is implied by count.
.. note:: See: :ref:`DVB Data Formats <legacy_dvb_decoder_formats>`
Return Value
~~~~~~~~~~~~
.. flat-table::
:header-rows: 0
:stub-columns: 0
- ..
- ``EPERM``
- :cspan:`1` Mode ``VIDEO_SOURCE_MEMORY`` not selected.
- ..
- ``ENOMEM``
- Attempted to write more data than the internal buffer can hold.
- ..
- ``EBADF``
- fd is not a valid open file descriptor.
요약·해설
legacy_dvb_video.rst:1-2430이 API는 새 드라이버에서 사용하면 안 되는 legacy DVB MPEG decoder 인터페이스입니다. Demux 또는 memory stream을 받아 재생 상태, event, aspect ratio, still picture, 속도, codec type, PTS와 frame count를 제어·조회합니다.
원문 symbol과 호출 선언은 그대로 보존했습니다. `video_display_format_t`/`video_displayformat_t`와 `VIDEO_GET_FRAME_COUNT`의 `*pts`처럼 선언과 의미가 어긋나는 부분은 번역 본문에 검수 지점으로 명시했습니다.