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
|
.. -*- 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``
Pointer to struct :c:type:`v4l2_input`.
Description
===========
To query the attributes of a video input applications initialize the
``index`` field of struct :c:type:`v4l2_input` and call the
:ref:`VIDIOC_ENUMINPUT` 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}|
.. c:type:: v4l2_input
.. flat-table:: struct v4l2_input
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
* - __u32
- ``index``
- Identifies the input, set by the application.
* - __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.
* - __u32
- ``type``
- Type of the input, see :ref:`input-type`.
* - __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`.
* - __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 :c:type:`v4l2_tuner` field ``index``. For
details on tuners see :ref:`tuner`.
* - :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`.
* - __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.
* - __u32
- ``capabilities``
- This field provides capabilities for the input. See
:ref:`input-capabilities` for flags.
* - __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
* - ``V4L2_INPUT_TYPE_TUNER``
- 1
- This input uses a tuner (RF demodulator).
* - ``V4L2_INPUT_TYPE_CAMERA``
- 2
- Any non-tuner video input, for example Composite Video,
S-Video, HDMI, camera sensor. The naming as ``_TYPE_CAMERA`` is historical,
today we would have called it ``_TYPE_VIDEO``.
* - ``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
* - :cspan:`2` General
* - ``V4L2_IN_ST_NO_POWER``
- 0x00000001
- Attached device is off.
* - ``V4L2_IN_ST_NO_SIGNAL``
- 0x00000002
-
* - ``V4L2_IN_ST_NO_COLOR``
- 0x00000004
- The hardware supports color decoding, but does not detect color
modulation in the signal.
* - :cspan:`2` Sensor Orientation
* - ``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.
* - ``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
* - :cspan:`2` Analog Video
* - ``V4L2_IN_ST_NO_H_LOCK``
- 0x00000100
- No horizontal sync lock.
* - ``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.
* - ``V4L2_IN_ST_NO_V_LOCK``
- 0x00000400
- No vertical sync lock.
* - ``V4L2_IN_ST_NO_STD_LOCK``
- 0x00000800
- No standard format lock in case of auto-detection format
by the component.
* - :cspan:`2` Digital Video
* - ``V4L2_IN_ST_NO_SYNC``
- 0x00010000
- No synchronization lock.
* - ``V4L2_IN_ST_NO_EQU``
- 0x00020000
- No equalizer lock.
* - ``V4L2_IN_ST_NO_CARRIER``
- 0x00040000
- Carrier recovery failed.
* - :cspan:`2` VCR and Set-Top Box
* - ``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.
* - ``V4L2_IN_ST_NO_ACCESS``
- 0x02000000
- Conditional access denied.
* - ``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
* - ``V4L2_IN_CAP_DV_TIMINGS``
- 0x00000002
- This input supports setting video timings by using
``VIDIOC_S_DV_TIMINGS``.
* - ``V4L2_IN_CAP_STD``
- 0x00000004
- This input supports setting the TV standard by using
``VIDIOC_S_STD``.
* - ``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 :c:type:`v4l2_input` ``index`` is out of
bounds.
|
