1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
|
.. -*- coding: utf-8; mode: rst -*-
.. _vidioc-g-dv-timings:
**********************************************
ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS
**********************************************
*man VIDIOC_G_DV_TIMINGS(2)*
VIDIOC_S_DV_TIMINGS
VIDIOC_SUBDEV_G_DV_TIMINGS
VIDIOC_SUBDEV_S_DV_TIMINGS
Get or set DV timings for input or output
Synopsis
========
.. c:function:: int ioctl( int fd, int request, struct v4l2_dv_timings *argp )
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
``request``
VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS,
VIDIOC_SUBDEV_G_DV_TIMINGS, VIDIOC_SUBDEV_S_DV_TIMINGS
``argp``
Description
===========
To set DV timings for the input or output, applications use the
``VIDIOC_S_DV_TIMINGS`` ioctl and to get the current timings,
applications use the ``VIDIOC_G_DV_TIMINGS`` ioctl. The detailed timing
information is filled in using the structure struct
:ref:`v4l2_dv_timings <v4l2-dv-timings>`. These ioctls take a
pointer to the struct :ref:`v4l2_dv_timings <v4l2-dv-timings>`
structure as argument. If the ioctl is not supported or the timing
values are not correct, the driver returns EINVAL error code.
The ``linux/v4l2-dv-timings.h`` header can be used to get the timings of
the formats in the :ref:`cea861` and :ref:`vesadmt` standards. If
the current input or output does not support DV timings (e.g. if
:ref:`VIDIOC_ENUMINPUT <vidioc-enuminput>` does not set the
``V4L2_IN_CAP_DV_TIMINGS`` flag), then ENODATA error code is returned.
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.
EINVAL
This ioctl is not supported, or the ``VIDIOC_S_DV_TIMINGS``
parameter was unsuitable.
ENODATA
Digital video timings are not supported for this input or output.
EBUSY
The device is busy and therefore can not change the timings.
.. _v4l2-bt-timings:
.. flat-table:: struct v4l2_bt_timings
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
- .. row 1
- __u32
- ``width``
- Width of the active video in pixels.
- .. row 2
- __u32
- ``height``
- Height of the active video frame in lines. So for interlaced
formats the height of the active video in each field is
``height``/2.
- .. row 3
- __u32
- ``interlaced``
- Progressive (0) or interlaced (1)
- .. row 4
- __u32
- ``polarities``
- This is a bit mask that defines polarities of sync signals. bit 0
(V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit
1 (V4L2_DV_HSYNC_POS_POL) is for horizontal sync polarity. If
the bit is set (1) it is positive polarity and if is cleared (0),
it is negative polarity.
- .. row 5
- __u64
- ``pixelclock``
- Pixel clock in Hz. Ex. 74.25MHz->74250000
- .. row 6
- __u32
- ``hfrontporch``
- Horizontal front porch in pixels
- .. row 7
- __u32
- ``hsync``
- Horizontal sync length in pixels
- .. row 8
- __u32
- ``hbackporch``
- Horizontal back porch in pixels
- .. row 9
- __u32
- ``vfrontporch``
- Vertical front porch in lines. For interlaced formats this refers
to the odd field (aka field 1).
- .. row 10
- __u32
- ``vsync``
- Vertical sync length in lines. For interlaced formats this refers
to the odd field (aka field 1).
- .. row 11
- __u32
- ``vbackporch``
- Vertical back porch in lines. For interlaced formats this refers
to the odd field (aka field 1).
- .. row 12
- __u32
- ``il_vfrontporch``
- Vertical front porch in lines for the even field (aka field 2) of
interlaced field formats. Must be 0 for progressive formats.
- .. row 13
- __u32
- ``il_vsync``
- Vertical sync length in lines for the even field (aka field 2) of
interlaced field formats. Must be 0 for progressive formats.
- .. row 14
- __u32
- ``il_vbackporch``
- Vertical back porch in lines for the even field (aka field 2) of
interlaced field formats. Must be 0 for progressive formats.
- .. row 15
- __u32
- ``standards``
- The video standard(s) this format belongs to. This will be filled
in by the driver. Applications must set this to 0. See
:ref:`dv-bt-standards` for a list of standards.
- .. row 16
- __u32
- ``flags``
- Several flags giving more information about the format. See
:ref:`dv-bt-flags` for a description of the flags.
.. _v4l2-dv-timings:
.. flat-table:: struct v4l2_dv_timings
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2 1
- .. row 1
- __u32
- ``type``
-
- Type of DV timings as listed in :ref:`dv-timing-types`.
- .. row 2
- union
-
-
- .. row 3
-
- struct :ref:`v4l2_bt_timings <v4l2-bt-timings>`
- ``bt``
- Timings defined by BT.656/1120 specifications
- .. row 4
-
- __u32
- ``reserved``\ [32]
-
.. _dv-timing-types:
.. flat-table:: DV Timing types
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
- .. row 1
- Timing type
- value
- Description
- .. row 2
-
-
-
- .. row 3
- V4L2_DV_BT_656_1120
- 0
- BT.656/1120 timings
.. _dv-bt-standards:
.. flat-table:: DV BT Timing standards
:header-rows: 0
:stub-columns: 0
- .. row 1
- Timing standard
- Description
- .. row 2
-
-
- .. row 3
- V4L2_DV_BT_STD_CEA861
- The timings follow the CEA-861 Digital TV Profile standard
- .. row 4
- V4L2_DV_BT_STD_DMT
- The timings follow the VESA Discrete Monitor Timings standard
- .. row 5
- V4L2_DV_BT_STD_CVT
- The timings follow the VESA Coordinated Video Timings standard
- .. row 6
- V4L2_DV_BT_STD_GTF
- The timings follow the VESA Generalized Timings Formula standard
.. _dv-bt-flags:
.. flat-table:: DV BT Timing flags
:header-rows: 0
:stub-columns: 0
- .. row 1
- Flag
- Description
- .. row 2
-
-
- .. row 3
- V4L2_DV_FL_REDUCED_BLANKING
- CVT/GTF specific: the timings use reduced blanking (CVT) or the
'Secondary GTF' curve (GTF). In both cases the horizontal and/or
vertical blanking intervals are reduced, allowing a higher
resolution over the same bandwidth. This is a read-only flag,
applications must not set this.
- .. row 4
- V4L2_DV_FL_CAN_REDUCE_FPS
- CEA-861 specific: set for CEA-861 formats with a framerate that is
a multiple of six. These formats can be optionally played at 1 /
1.001 speed to be compatible with 60 Hz based standards such as
NTSC and PAL-M that use a framerate of 29.97 frames per second. If
the transmitter can't generate such frequencies, then the flag
will also be cleared. This is a read-only flag, applications must
not set this.
- .. row 5
- V4L2_DV_FL_REDUCED_FPS
- CEA-861 specific: only valid for video transmitters, the flag is
cleared by receivers. It is also only valid for formats with the
V4L2_DV_FL_CAN_REDUCE_FPS flag set, for other formats the
flag will be cleared by the driver. If the application sets this
flag, then the pixelclock used to set up the transmitter is
divided by 1.001 to make it compatible with NTSC framerates. If
the transmitter can't generate such frequencies, then the flag
will also be cleared.
- .. row 6
- V4L2_DV_FL_HALF_LINE
- Specific to interlaced formats: if set, then the vertical
frontporch of field 1 (aka the odd field) is really one half-line
longer and the vertical backporch of field 2 (aka the even field)
is really one half-line shorter, so each field has exactly the
same number of half-lines. Whether half-lines can be detected or
used depends on the hardware.
- .. row 7
- V4L2_DV_FL_IS_CE_VIDEO
- If set, then this is a Consumer Electronics (CE) video format.
Such formats differ from other formats (commonly called IT
formats) in that if R'G'B' encoding is used then by default the
R'G'B' values use limited range (i.e. 16-235) as opposed to full
range (i.e. 0-255). All formats defined in CEA-861 except for the
640x480p59.94 format are CE formats.
.. ------------------------------------------------------------------------------
.. This file was automatically converted from DocBook-XML with the dbxml
.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
.. from the linux kernel, refer to:
..
.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
.. ------------------------------------------------------------------------------
|
