1.. Permission is granted to copy, distribute and/or modify this
2.. document under the terms of the GNU Free Documentation License,
3.. Version 1.1 or any later version published by the Free Software
4.. Foundation, with no Invariant Sections, no Front-Cover Texts
5.. and no Back-Cover Texts. A copy of the license is included at
6.. Documentation/userspace-api/media/fdl-appendix.rst.
7..
8.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
9
10.. _VIDIOC_ENUMOUTPUT:
11
12***********************
13ioctl VIDIOC_ENUMOUTPUT
14***********************
15
16Name
17====
18
19VIDIOC_ENUMOUTPUT - Enumerate video outputs
20
21
22Synopsis
23========
24
25.. c:function:: int ioctl( int fd, VIDIOC_ENUMOUTPUT, struct v4l2_output *argp )
26    :name: VIDIOC_ENUMOUTPUT
27
28
29Arguments
30=========
31
32``fd``
33    File descriptor returned by :ref:`open() <func-open>`.
34
35``argp``
36    Pointer to struct :c:type:`v4l2_output`.
37
38
39Description
40===========
41
42To query the attributes of a video outputs applications initialize the
43``index`` field of struct :c:type:`v4l2_output` and call
44the :ref:`VIDIOC_ENUMOUTPUT` with a pointer to this structure.
45Drivers fill the rest of the structure or return an ``EINVAL`` error code
46when the index is out of bounds. To enumerate all outputs applications
47shall begin at index zero, incrementing by one until the driver returns
48``EINVAL``.
49
50
51.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
52
53.. c:type:: v4l2_output
54
55.. flat-table:: struct v4l2_output
56    :header-rows:  0
57    :stub-columns: 0
58    :widths:       1 1 2
59
60    * - __u32
61      - ``index``
62      - Identifies the output, set by the application.
63    * - __u8
64      - ``name``\ [32]
65      - Name of the video output, a NUL-terminated ASCII string, for
66	example: "Vout". This information is intended for the user,
67	preferably the connector label on the device itself.
68    * - __u32
69      - ``type``
70      - Type of the output, see :ref:`output-type`.
71    * - __u32
72      - ``audioset``
73      - Drivers can enumerate up to 32 video and audio outputs. This field
74	shows which audio outputs were selectable as the current output if
75	this was the currently selected video output. It is a bit mask.
76	The LSB corresponds to audio output 0, the MSB to output 31. Any
77	number of bits can be set, or none.
78
79	When the driver does not enumerate audio outputs no bits must be
80	set. Applications shall not interpret this as lack of audio
81	support. Drivers may automatically select audio outputs without
82	enumerating them.
83
84	For details on audio outputs and how to select the current output
85	see :ref:`audio`.
86    * - __u32
87      - ``modulator``
88      - Output devices can have zero or more RF modulators. When the
89	``type`` is ``V4L2_OUTPUT_TYPE_MODULATOR`` this is an RF connector
90	and this field identifies the modulator. It corresponds to struct
91	:c:type:`v4l2_modulator` field ``index``. For
92	details on modulators see :ref:`tuner`.
93    * - :ref:`v4l2_std_id <v4l2-std-id>`
94      - ``std``
95      - Every video output supports one or more different video standards.
96	This field is a set of all supported standards. For details on
97	video standards and how to switch see :ref:`standard`.
98    * - __u32
99      - ``capabilities``
100      - This field provides capabilities for the output. See
101	:ref:`output-capabilities` for flags.
102    * - __u32
103      - ``reserved``\ [3]
104      - Reserved for future extensions. Drivers must set the array to
105	zero.
106
107
108
109.. tabularcolumns:: |p{7.0cm}|p{1.8cm}|p{8.7cm}|
110
111.. _output-type:
112
113.. flat-table:: Output Type
114    :header-rows:  0
115    :stub-columns: 0
116    :widths:       3 1 4
117
118    * - ``V4L2_OUTPUT_TYPE_MODULATOR``
119      - 1
120      - This output is an analog TV modulator.
121    * - ``V4L2_OUTPUT_TYPE_ANALOG``
122      - 2
123      - Any non-modulator video output, for example Composite Video,
124	S-Video, HDMI. The naming as ``_TYPE_ANALOG`` is historical,
125	today we would have called it ``_TYPE_VIDEO``.
126    * - ``V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY``
127      - 3
128      - The video output will be copied to a :ref:`video overlay <overlay>`.
129
130
131
132.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
133
134.. _output-capabilities:
135
136.. flat-table:: Output capabilities
137    :header-rows:  0
138    :stub-columns: 0
139    :widths:       3 1 4
140
141    * - ``V4L2_OUT_CAP_DV_TIMINGS``
142      - 0x00000002
143      - This output supports setting video timings by using
144	``VIDIOC_S_DV_TIMINGS``.
145    * - ``V4L2_OUT_CAP_STD``
146      - 0x00000004
147      - This output supports setting the TV standard by using
148	``VIDIOC_S_STD``.
149    * - ``V4L2_OUT_CAP_NATIVE_SIZE``
150      - 0x00000008
151      - This output supports setting the native size using the
152	``V4L2_SEL_TGT_NATIVE_SIZE`` selection target, see
153	:ref:`v4l2-selections-common`.
154
155
156Return Value
157============
158
159On success 0 is returned, on error -1 and the ``errno`` variable is set
160appropriately. The generic error codes are described at the
161:ref:`Generic Error Codes <gen-errors>` chapter.
162
163EINVAL
164    The struct :c:type:`v4l2_output` ``index`` is out of
165    bounds.
166