1 .. SPDX-License-Identifier: GFDL-1.1-no-invari 1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2 .. c:namespace:: V4L 2 .. c:namespace:: V4L
3 3
4 .. _VIDIOC_G_AUDOUT: 4 .. _VIDIOC_G_AUDOUT:
5 5
6 ************************************** 6 **************************************
7 ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT 7 ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT
8 ************************************** 8 **************************************
9 9
10 Name 10 Name
11 ==== 11 ====
12 12
13 VIDIOC_G_AUDOUT - VIDIOC_S_AUDOUT - Query or s 13 VIDIOC_G_AUDOUT - VIDIOC_S_AUDOUT - Query or select the current audio output
14 14
15 Synopsis 15 Synopsis
16 ======== 16 ========
17 17
18 .. c:macro:: VIDIOC_G_AUDOUT 18 .. c:macro:: VIDIOC_G_AUDOUT
19 19
20 ``int ioctl(int fd, VIDIOC_G_AUDOUT, struct v4 20 ``int ioctl(int fd, VIDIOC_G_AUDOUT, struct v4l2_audioout *argp)``
21 21
22 .. c:macro:: VIDIOC_S_AUDOUT 22 .. c:macro:: VIDIOC_S_AUDOUT
23 23
24 ``int ioctl(int fd, VIDIOC_S_AUDOUT, const str 24 ``int ioctl(int fd, VIDIOC_S_AUDOUT, const struct v4l2_audioout *argp)``
25 25
26 Arguments 26 Arguments
27 ========= 27 =========
28 28
29 ``fd`` 29 ``fd``
30 File descriptor returned by :c:func:`open( 30 File descriptor returned by :c:func:`open()`.
31 31
32 ``argp`` 32 ``argp``
33 Pointer to struct :c:type:`v4l2_audioout`. 33 Pointer to struct :c:type:`v4l2_audioout`.
34 34
35 Description 35 Description
36 =========== 36 ===========
37 37
38 To query the current audio output applications 38 To query the current audio output applications zero out the ``reserved``
39 array of a struct :c:type:`v4l2_audioout` and 39 array of a struct :c:type:`v4l2_audioout` and call the
40 ``VIDIOC_G_AUDOUT`` ioctl with a pointer to th 40 ``VIDIOC_G_AUDOUT`` ioctl with a pointer to this structure. Drivers fill
41 the rest of the structure or return an ``EINVA 41 the rest of the structure or return an ``EINVAL`` error code when the device
42 has no audio inputs, or none which combine wit 42 has no audio inputs, or none which combine with the current video
43 output. 43 output.
44 44
45 Audio outputs have no writable properties. Nev 45 Audio outputs have no writable properties. Nevertheless, to select the
46 current audio output applications can initiali 46 current audio output applications can initialize the ``index`` field and
47 ``reserved`` array (which in the future may co 47 ``reserved`` array (which in the future may contain writable properties)
48 of a struct :c:type:`v4l2_audioout` structure 48 of a struct :c:type:`v4l2_audioout` structure and call the
49 ``VIDIOC_S_AUDOUT`` ioctl. Drivers switch to t 49 ``VIDIOC_S_AUDOUT`` ioctl. Drivers switch to the requested output or
50 return the ``EINVAL`` error code when the inde 50 return the ``EINVAL`` error code when the index is out of bounds. This is a
51 write-only ioctl, it does not return the curre 51 write-only ioctl, it does not return the current audio output attributes
52 as ``VIDIOC_G_AUDOUT`` does. 52 as ``VIDIOC_G_AUDOUT`` does.
53 53
54 .. note:: 54 .. note::
55 55
56 Connectors on a TV card to loop back the re 56 Connectors on a TV card to loop back the received audio signal
57 to a sound card are not audio outputs in th 57 to a sound card are not audio outputs in this sense.
58 58
59 .. c:type:: v4l2_audioout 59 .. c:type:: v4l2_audioout
60 60
61 .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm 61 .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
62 62
63 .. flat-table:: struct v4l2_audioout 63 .. flat-table:: struct v4l2_audioout
64 :header-rows: 0 64 :header-rows: 0
65 :stub-columns: 0 65 :stub-columns: 0
66 :widths: 1 1 2 66 :widths: 1 1 2
67 67
68 * - __u32 68 * - __u32
69 - ``index`` 69 - ``index``
70 - Identifies the audio output, set by th 70 - Identifies the audio output, set by the driver or application.
71 * - __u8 71 * - __u8
72 - ``name``\ [32] 72 - ``name``\ [32]
73 - Name of the audio output, a NUL-termin 73 - Name of the audio output, a NUL-terminated ASCII string, for
74 example: "Line Out". This information 74 example: "Line Out". This information is intended for the user,
75 preferably the connector label on the 75 preferably the connector label on the device itself.
76 * - __u32 76 * - __u32
77 - ``capability`` 77 - ``capability``
78 - Audio capability flags, none defined y 78 - Audio capability flags, none defined yet. Drivers must set this
79 field to zero. 79 field to zero.
80 * - __u32 80 * - __u32
81 - ``mode`` 81 - ``mode``
82 - Audio mode, none defined yet. Drivers 82 - Audio mode, none defined yet. Drivers and applications (on
83 ``VIDIOC_S_AUDOUT``) must set this fie 83 ``VIDIOC_S_AUDOUT``) must set this field to zero.
84 * - __u32 84 * - __u32
85 - ``reserved``\ [2] 85 - ``reserved``\ [2]
86 - Reserved for future extensions. Driver 86 - Reserved for future extensions. Drivers and applications must set
87 the array to zero. 87 the array to zero.
88 88
89 Return Value 89 Return Value
90 ============ 90 ============
91 91
92 On success 0 is returned, on error -1 and the 92 On success 0 is returned, on error -1 and the ``errno`` variable is set
93 appropriately. The generic error codes are des 93 appropriately. The generic error codes are described at the
94 :ref:`Generic Error Codes <gen-errors>` chapte 94 :ref:`Generic Error Codes <gen-errors>` chapter.
95 95
96 EINVAL 96 EINVAL
97 No audio outputs combine with the current 97 No audio outputs combine with the current video output, or the
98 number of the selected audio output is out 98 number of the selected audio output is out of bounds or it does not
99 combine. 99 combine.
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