1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2.. c:namespace:: V4L
3
4.. _VIDIOC_G_STD:
5
6**************************************************************************
7ioctl VIDIOC_G_STD, VIDIOC_S_STD, VIDIOC_SUBDEV_G_STD, VIDIOC_SUBDEV_S_STD
8**************************************************************************
9
10Name
11====
12
13VIDIOC_G_STD - VIDIOC_S_STD - VIDIOC_SUBDEV_G_STD - VIDIOC_SUBDEV_S_STD - Query or select the video standard of the current input
14
15Synopsis
16========
17
18.. c:macro:: VIDIOC_G_STD
19
20``int ioctl(int fd, VIDIOC_G_STD, v4l2_std_id *argp)``
21
22.. c:macro:: VIDIOC_S_STD
23
24``int ioctl(int fd, VIDIOC_S_STD, const v4l2_std_id *argp)``
25
26.. c:macro:: VIDIOC_SUBDEV_G_STD
27
28``int ioctl(int fd, VIDIOC_SUBDEV_G_STD, v4l2_std_id *argp)``
29
30.. c:macro:: VIDIOC_SUBDEV_S_STD
31
32``int ioctl(int fd, VIDIOC_SUBDEV_S_STD, const v4l2_std_id *argp)``
33
34Arguments
35=========
36
37``fd``
38    File descriptor returned by :c:func:`open()`.
39
40``argp``
41    Pointer to :c:type:`v4l2_std_id`.
42
43Description
44===========
45
46To query and select the current video standard applications use the
47:ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a
48:ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`
49can return a single flag or a set of flags as in struct
50:c:type:`v4l2_standard` field ``id``. The flags must be
51unambiguous such that they appear in only one enumerated
52struct :c:type:`v4l2_standard` structure.
53
54:ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it
55does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When
56no flags are given or the current input does not support the requested
57standard the driver returns an ``EINVAL`` error code. When the standard set
58is ambiguous drivers may return ``EINVAL`` or choose any of the requested
59standards. If the current input or output does not support standard
60video timings (e.g. if :ref:`VIDIOC_ENUMINPUT`
61does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is
62returned.
63
64Calling ``VIDIOC_SUBDEV_S_STD`` on a subdev device node that has been registered
65in read-only mode is not allowed. An error is returned and the errno variable is
66set to ``-EPERM``.
67
68Return Value
69============
70
71On success 0 is returned, on error -1 and the ``errno`` variable is set
72appropriately. The generic error codes are described at the
73:ref:`Generic Error Codes <gen-errors>` chapter.
74
75EINVAL
76    The :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable.
77
78ENODATA
79    Standard video timings are not supported for this input or output.
80
81EPERM
82    ``VIDIOC_SUBDEV_S_STD`` has been called on a read-only subdevice.
83