1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2 .. c:namespace:: V4L
3
4 .. _VIDIOC_ENUMOUTPUT:
5
6 ***********************
7 ioctl VIDIOC_ENUMOUTPUT
8 ***********************
9
10 Name
11 ====
12
13 VIDIOC_ENUMOUTPUT - Enumerate video outputs
14
15 Synopsis
16 ========
17
18 .. c:macro:: VIDIOC_ENUMOUTPUT
19
20 ``int ioctl(int fd, VIDIOC_ENUMOUTPUT, struct v4l2_output *argp)``
21
22 Arguments
23 =========
24
25 ``fd``
26 File descriptor returned by :c:func:`open()`.
27
28 ``argp``
29 Pointer to struct :c:type:`v4l2_output`.
30
31 Description
32 ===========
33
34 To query the attributes of a video outputs applications initialize the
35 ``index`` field of struct :c:type:`v4l2_output` and call
36 the :ref:`VIDIOC_ENUMOUTPUT` with a pointer to this structure.
37 Drivers fill the rest of the structure or return an ``EINVAL`` error code
38 when the index is out of bounds. To enumerate all outputs applications
39 shall begin at index zero, incrementing by one until the driver returns
40 ``EINVAL``.
41
42 .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
43
44 .. c:type:: v4l2_output
45
46 .. flat-table:: struct v4l2_output
47 :header-rows: 0
48 :stub-columns: 0
49 :widths: 1 1 2
50
51 * - __u32
52 - ``index``
53 - Identifies the output, set by the application.
54 * - __u8
55 - ``name``\ [32]
56 - Name of the video output, a NUL-terminated ASCII string, for
57 example: "Vout". This information is intended for the user,
58 preferably the connector label on the device itself.
59 * - __u32
60 - ``type``
61 - Type of the output, see :ref:`output-type`.
62 * - __u32
63 - ``audioset``
64 - Drivers can enumerate up to 32 video and audio outputs. This field
65 shows which audio outputs were selectable as the current output if
66 this was the currently selected video output. It is a bit mask.
67 The LSB corresponds to audio output 0, the MSB to output 31. Any
68 number of bits can be set, or none.
69
70 When the driver does not enumerate audio outputs no bits must be
71 set. Applications shall not interpret this as lack of audio
72 support. Drivers may automatically select audio outputs without
73 enumerating them.
74
75 For details on audio outputs and how to select the current output
76 see :ref:`audio`.
77 * - __u32
78 - ``modulator``
79 - Output devices can have zero or more RF modulators. When the
80 ``type`` is ``V4L2_OUTPUT_TYPE_MODULATOR`` this is an RF connector
81 and this field identifies the modulator. It corresponds to struct
82 :c:type:`v4l2_modulator` field ``index``. For
83 details on modulators see :ref:`tuner`.
84 * - :ref:`v4l2_std_id <v4l2-std-id>`
85 - ``std``
86 - Every video output supports one or more different video standards.
87 This field is a set of all supported standards. For details on
88 video standards and how to switch see :ref:`standard`.
89 * - __u32
90 - ``capabilities``
91 - This field provides capabilities for the output. See
92 :ref:`output-capabilities` for flags.
93 * - __u32
94 - ``reserved``\ [3]
95 - Reserved for future extensions. Drivers must set the array to
96 zero.
97
98
99 .. tabularcolumns:: |p{7.5cm}|p{0.6cm}|p{9.2cm}|
100
101 .. _output-type:
102
103 .. flat-table:: Output Type
104 :header-rows: 0
105 :stub-columns: 0
106 :widths: 3 1 4
107
108 * - ``V4L2_OUTPUT_TYPE_MODULATOR``
109 - 1
110 - This output is an analog TV modulator.
111 * - ``V4L2_OUTPUT_TYPE_ANALOG``
112 - 2
113 - Any non-modulator video output, for example Composite Video,
114 S-Video, HDMI. The naming as ``_TYPE_ANALOG`` is historical,
115 today we would have called it ``_TYPE_VIDEO``.
116 * - ``V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY``
117 - 3
118 - The video output will be copied to a :ref:`video overlay <overlay>`.
119
120
121 .. tabularcolumns:: |p{6.4cm}|p{2.4cm}|p{8.5cm}|
122
123 .. _output-capabilities:
124
125 .. flat-table:: Output capabilities
126 :header-rows: 0
127 :stub-columns: 0
128 :widths: 3 1 4
129
130 * - ``V4L2_OUT_CAP_DV_TIMINGS``
131 - 0x00000002
132 - This output supports setting video timings by using
133 ``VIDIOC_S_DV_TIMINGS``.
134 * - ``V4L2_OUT_CAP_STD``
135 - 0x00000004
136 - This output supports setting the TV standard by using
137 ``VIDIOC_S_STD``.
138 * - ``V4L2_OUT_CAP_NATIVE_SIZE``
139 - 0x00000008
140 - This output supports setting the native size using the
141 ``V4L2_SEL_TGT_NATIVE_SIZE`` selection target, see
142 :ref:`v4l2-selections-common`.
143
144 Return Value
145 ============
146
147 On success 0 is returned, on error -1 and the ``errno`` variable is set
148 appropriately. The generic error codes are described at the
149 :ref:`Generic Error Codes <gen-errors>` chapter.
150
151 EINVAL
152 The struct :c:type:`v4l2_output` ``index`` is out of
153 bounds.
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