1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2 .. c:namespace:: V4L
3
4 .. _VIDIOC_ENUM_DV_TIMINGS:
5
6 ***********************************************************
7 ioctl VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS
8 ***********************************************************
9
10 Name
11 ====
12
13 VIDIOC_ENUM_DV_TIMINGS - VIDIOC_SUBDEV_ENUM_DV_TIMINGS - Enumerate supported Digital Video timings
14
15 Synopsis
16 ========
17
18 .. c:macro:: VIDIOC_ENUM_DV_TIMINGS
19
20 ``int ioctl(int fd, VIDIOC_ENUM_DV_TIMINGS, struct v4l2_enum_dv_timings *argp)``
21
22 .. c:macro:: VIDIOC_SUBDEV_ENUM_DV_TIMINGS
23
24 ``int ioctl(int fd, VIDIOC_SUBDEV_ENUM_DV_TIMINGS, struct v4l2_enum_dv_timings *argp)``
25
26 Arguments
27 =========
28
29 ``fd``
30 File descriptor returned by :c:func:`open()`.
31
32 ``argp``
33 Pointer to struct :c:type:`v4l2_enum_dv_timings`.
34
35 Description
36 ===========
37
38 While some DV receivers or transmitters support a wide range of timings,
39 others support only a limited number of timings. With this ioctl
40 applications can enumerate a list of known supported timings. Call
41 :ref:`VIDIOC_DV_TIMINGS_CAP` to check if it
42 also supports other standards or even custom timings that are not in
43 this list.
44
45 To query the available timings, applications initialize the ``index``
46 field, set the ``pad`` field to 0, zero the reserved array of struct
47 :c:type:`v4l2_enum_dv_timings` and call the
48 ``VIDIOC_ENUM_DV_TIMINGS`` ioctl on a video node with a pointer to this
49 structure. Drivers fill the rest of the structure or return an ``EINVAL``
50 error code when the index is out of bounds. To enumerate all supported
51 DV timings, applications shall begin at index zero, incrementing by one
52 until the driver returns ``EINVAL``.
53
54 .. note::
55
56 Drivers may enumerate a different set of DV timings after
57 switching the video input or output.
58
59 When implemented by the driver DV timings of subdevices can be queried
60 by calling the ``VIDIOC_SUBDEV_ENUM_DV_TIMINGS`` ioctl directly on a
61 subdevice node. The DV timings are specific to inputs (for DV receivers)
62 or outputs (for DV transmitters), applications must specify the desired
63 pad number in the struct
64 :c:type:`v4l2_enum_dv_timings` ``pad`` field.
65 Attempts to enumerate timings on a pad that doesn't support them will
66 return an ``EINVAL`` error code.
67
68 .. c:type:: v4l2_enum_dv_timings
69
70 .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
71
72 .. flat-table:: struct v4l2_enum_dv_timings
73 :header-rows: 0
74 :stub-columns: 0
75 :widths: 1 1 2
76
77 * - __u32
78 - ``index``
79 - Number of the DV timings, set by the application.
80 * - __u32
81 - ``pad``
82 - Pad number as reported by the media controller API. This field is
83 only used when operating on a subdevice node. When operating on a
84 video node applications must set this field to zero.
85 * - __u32
86 - ``reserved``\ [2]
87 - Reserved for future extensions. Drivers and applications must set
88 the array to zero.
89 * - struct :c:type:`v4l2_dv_timings`
90 - ``timings``
91 - The timings.
92
93 Return Value
94 ============
95
96 On success 0 is returned, on error -1 and the ``errno`` variable is set
97 appropriately. The generic error codes are described at the
98 :ref:`Generic Error Codes <gen-errors>` chapter.
99
100 EINVAL
101 The struct :c:type:`v4l2_enum_dv_timings`
102 ``index`` is out of bounds or the ``pad`` number is invalid.
103
104 ENODATA
105 Digital video presets are not supported for this input or output.
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