1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2.. c:namespace:: V4L
3
4.. _VIDIOC_ENUM_DV_TIMINGS:
5
6***********************************************************
7ioctl VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS
8***********************************************************
9
10Name
11====
12
13VIDIOC_ENUM_DV_TIMINGS - VIDIOC_SUBDEV_ENUM_DV_TIMINGS - Enumerate supported Digital Video timings
14
15Synopsis
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
26Arguments
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
35Description
36===========
37
38While some DV receivers or transmitters support a wide range of timings,
39others support only a limited number of timings. With this ioctl
40applications can enumerate a list of known supported timings. Call
41:ref:`VIDIOC_DV_TIMINGS_CAP` to check if it
42also supports other standards or even custom timings that are not in
43this list.
44
45To query the available timings, applications initialize the ``index``
46field, 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
49structure. Drivers fill the rest of the structure or return an ``EINVAL``
50error code when the index is out of bounds. To enumerate all supported
51DV timings, applications shall begin at index zero, incrementing by one
52until 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
59When implemented by the driver DV timings of subdevices can be queried
60by calling the ``VIDIOC_SUBDEV_ENUM_DV_TIMINGS`` ioctl directly on a
61subdevice node. The DV timings are specific to inputs (for DV receivers)
62or outputs (for DV transmitters), applications must specify the desired
63pad number in the struct
64:c:type:`v4l2_enum_dv_timings` ``pad`` field.
65Attempts to enumerate timings on a pad that doesn't support them will
66return 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
93Return Value
94============
95
96On success 0 is returned, on error -1 and the ``errno`` variable is set
97appropriately. The generic error codes are described at the
98:ref:`Generic Error Codes <gen-errors>` chapter.
99
100EINVAL
101    The struct :c:type:`v4l2_enum_dv_timings`
102    ``index`` is out of bounds or the ``pad`` number is invalid.
103
104ENODATA
105    Digital video presets are not supported for this input or output.
106