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
|
.. -*- coding: utf-8; mode: rst -*-
.. _VIDIOC_ENUMOUTPUT:
***********************
ioctl VIDIOC_ENUMOUTPUT
***********************
Name
====
VIDIOC_ENUMOUTPUT - Enumerate video outputs
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, struct v4l2_output *argp )
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
``request``
VIDIOC_ENUMOUTPUT
``argp``
Description
===========
To query the attributes of a video outputs applications initialize the
``index`` field of struct :ref:`v4l2_output <v4l2-output>` and call
the :ref:`VIDIOC_ENUMOUTPUT` 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 outputs applications
shall begin at index zero, incrementing by one until the driver returns
EINVAL.
.. _v4l2-output:
.. flat-table:: struct v4l2_output
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
- .. row 1
- __u32
- ``index``
- Identifies the output, set by the application.
- .. row 2
- __u8
- ``name``\ \[32\]
- Name of the video output, a NUL-terminated ASCII string, for
example: "Vout". This information is intended for the user,
preferably the connector label on the device itself.
- .. row 3
- __u32
- ``type``
- Type of the output, see :ref:`output-type`.
- .. row 4
- __u32
- ``audioset``
- Drivers can enumerate up to 32 video and audio outputs. This field
shows which audio outputs were selectable as the current output if
this was the currently selected video output. It is a bit mask.
The LSB corresponds to audio output 0, the MSB to output 31. Any
number of bits can be set, or none.
When the driver does not enumerate audio outputs no bits must be
set. Applications shall not interpret this as lack of audio
support. Drivers may automatically select audio outputs without
enumerating them.
For details on audio outputs and how to select the current output
see :ref:`audio`.
- .. row 5
- __u32
- ``modulator``
- Output devices can have zero or more RF modulators. When the
``type`` is ``V4L2_OUTPUT_TYPE_MODULATOR`` this is an RF connector
and this field identifies the modulator. It corresponds to struct
:ref:`v4l2_modulator <v4l2-modulator>` field ``index``. For
details on modulators see :ref:`tuner`.
- .. row 6
- :ref:`v4l2_std_id <v4l2-std-id>`
- ``std``
- Every video output 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
- ``capabilities``
- This field provides capabilities for the output. See
:ref:`output-capabilities` for flags.
- .. row 8
- __u32
- ``reserved``\ \[3\]
- Reserved for future extensions. Drivers must set the array to
zero.
.. _output-type:
.. flat-table:: Output Type
:header-rows: 0
:stub-columns: 0
:widths: 3 1 4
- .. row 1
- ``V4L2_OUTPUT_TYPE_MODULATOR``
- 1
- This output is an analog TV modulator.
- .. row 2
- ``V4L2_OUTPUT_TYPE_ANALOG``
- 2
- Analog baseband output, for example Composite / CVBS, S-Video,
RGB.
- .. row 3
- ``V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY``
- 3
- [?]
.. _output-capabilities:
.. flat-table:: Output capabilities
:header-rows: 0
:stub-columns: 0
:widths: 3 1 4
- .. row 1
- ``V4L2_OUT_CAP_DV_TIMINGS``
- 0x00000002
- This output supports setting video timings by using
VIDIOC_S_DV_TIMINGS.
- .. row 2
- ``V4L2_OUT_CAP_STD``
- 0x00000004
- This output supports setting the TV standard by using
VIDIOC_S_STD.
- .. row 3
- ``V4L2_OUT_CAP_NATIVE_SIZE``
- 0x00000008
- This output 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_output <v4l2-output>` ``index`` is out of
bounds.
|
