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
|
.. -*- coding: utf-8; mode: rst -*-
.. _VIDIOC_ENUMINPUT:
**********************
ioctl VIDIOC_ENUMINPUT
**********************
Name
====
VIDIOC_ENUMINPUT - Enumerate video inputs
Synopsis
========
.. c:function:: int ioctl( int fd, VIDIOC_ENUMINPUT, struct v4l2_input *argp )
:name: VIDIOC_ENUMINPUT
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
``argp``
Description
===========
To query the attributes of a video input applications initialize the
``index`` field of struct :ref:`v4l2_input <v4l2-input>` and call the
:ref:`VIDIOC_ENUMINPUT` ioctl with a pointer to this structure. Drivers
fill the rest of the structure or return an ``EINVAL`` error code when the
index is out of bounds. To enumerate all inputs applications shall begin
at index zero, incrementing by one until the driver returns ``EINVAL``.
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
.. _v4l2-input:
.. flat-table:: struct v4l2_input
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
- .. row 1
- __u32
- ``index``
- Identifies the input, set by the application.
- .. row 2
- __u8
- ``name``\ [32]
- Name of the video input, a NUL-terminated ASCII string, for
example: "Vin (Composite 2)". This information is intended for the
user, preferably the connector label on the device itself.
- .. row 3
- __u32
- ``type``
- Type of the input, see :ref:`input-type`.
- .. row 4
- __u32
- ``audioset``
- Drivers can enumerate up to 32 video and audio inputs. This field
shows which audio inputs were selectable as audio source if this
was the currently selected video input. It is a bit mask. The LSB
corresponds to audio input 0, the MSB to input 31. Any number of
bits can be set, or none.
When the driver does not enumerate audio inputs no bits must be
set. Applications shall not interpret this as lack of audio
support. Some drivers automatically select audio sources and do
not enumerate them since there is no choice anyway.
For details on audio inputs and how to select the current input
see :ref:`audio`.
- .. row 5
- __u32
- ``tuner``
- Capture devices can have zero or more tuners (RF demodulators).
When the ``type`` is set to ``V4L2_INPUT_TYPE_TUNER`` this is an
RF connector and this field identifies the tuner. It corresponds
to struct :ref:`v4l2_tuner <v4l2-tuner>` field ``index``. For
details on tuners see :ref:`tuner`.
- .. row 6
- :ref:`v4l2_std_id <v4l2-std-id>`
- ``std``
- Every video input supports one or more different video standards.
This field is a set of all supported standards. For details on
video standards and how to switch see :ref:`standard`.
- .. row 7
- __u32
- ``status``
- This field provides status information about the input. See
:ref:`input-status` for flags. With the exception of the sensor
orientation bits ``status`` is only valid when this is the current
input.
- .. row 8
- __u32
- ``capabilities``
- This field provides capabilities for the input. See
:ref:`input-capabilities` for flags.
- .. row 9
- __u32
- ``reserved``\ [3]
- Reserved for future extensions. Drivers must set the array to
zero.
.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
.. _input-type:
.. flat-table:: Input Types
:header-rows: 0
:stub-columns: 0
:widths: 3 1 4
- .. row 1
- ``V4L2_INPUT_TYPE_TUNER``
- 1
- This input uses a tuner (RF demodulator).
- .. row 2
- ``V4L2_INPUT_TYPE_CAMERA``
- 2
- Analog baseband input, for example CVBS / Composite Video,
S-Video, RGB.
- .. row 3
- ``V4L2_INPUT_TYPE_TOUCH``
- 3
- This input is a touch device for capturing raw touch data.
.. tabularcolumns:: |p{4.8cm}|p{2.6cm}|p{10.1cm}|
.. _input-status:
.. flat-table:: Input Status Flags
:header-rows: 0
:stub-columns: 0
- .. row 1
- :cspan:`2` General
- .. row 2
- ``V4L2_IN_ST_NO_POWER``
- 0x00000001
- Attached device is off.
- .. row 3
- ``V4L2_IN_ST_NO_SIGNAL``
- 0x00000002
-
- .. row 4
- ``V4L2_IN_ST_NO_COLOR``
- 0x00000004
- The hardware supports color decoding, but does not detect color
modulation in the signal.
- .. row 5
- :cspan:`2` Sensor Orientation
- .. row 6
- ``V4L2_IN_ST_HFLIP``
- 0x00000010
- The input is connected to a device that produces a signal that is
flipped horizontally and does not correct this before passing the
signal to userspace.
- .. row 7
- ``V4L2_IN_ST_VFLIP``
- 0x00000020
- The input is connected to a device that produces a signal that is
flipped vertically and does not correct this before passing the
signal to userspace.
.. note:: A 180 degree rotation is the same as HFLIP | VFLIP
- .. row 8
- :cspan:`2` Analog Video
- .. row 9
- ``V4L2_IN_ST_NO_H_LOCK``
- 0x00000100
- No horizontal sync lock.
- .. row 10
- ``V4L2_IN_ST_COLOR_KILL``
- 0x00000200
- A color killer circuit automatically disables color decoding when
it detects no color modulation. When this flag is set the color
killer is enabled *and* has shut off color decoding.
- .. row 11
- :cspan:`2` Digital Video
- .. row 12
- ``V4L2_IN_ST_NO_SYNC``
- 0x00010000
- No synchronization lock.
- .. row 13
- ``V4L2_IN_ST_NO_EQU``
- 0x00020000
- No equalizer lock.
- .. row 14
- ``V4L2_IN_ST_NO_CARRIER``
- 0x00040000
- Carrier recovery failed.
- .. row 15
- :cspan:`2` VCR and Set-Top Box
- .. row 16
- ``V4L2_IN_ST_MACROVISION``
- 0x01000000
- Macrovision is an analog copy prevention system mangling the video
signal to confuse video recorders. When this flag is set
Macrovision has been detected.
- .. row 17
- ``V4L2_IN_ST_NO_ACCESS``
- 0x02000000
- Conditional access denied.
- .. row 18
- ``V4L2_IN_ST_VTR``
- 0x04000000
- VTR time constant. [?]
.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
.. _input-capabilities:
.. flat-table:: Input capabilities
:header-rows: 0
:stub-columns: 0
:widths: 3 1 4
- .. row 1
- ``V4L2_IN_CAP_DV_TIMINGS``
- 0x00000002
- This input supports setting video timings by using
VIDIOC_S_DV_TIMINGS.
- .. row 2
- ``V4L2_IN_CAP_STD``
- 0x00000004
- This input supports setting the TV standard by using
VIDIOC_S_STD.
- .. row 3
- ``V4L2_IN_CAP_NATIVE_SIZE``
- 0x00000008
- This input supports setting the native size using the
``V4L2_SEL_TGT_NATIVE_SIZE`` selection target, see
:ref:`v4l2-selections-common`.
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
The struct :ref:`v4l2_input <v4l2-input>` ``index`` is out of
bounds.
|