blob: cd856ad21a289e5fd4fa982ec45c391bda3ba0ba (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
.. -*- coding: utf-8; mode: rst -*-
.. _VIDIOC_G_STD:
********************************
ioctl VIDIOC_G_STD, VIDIOC_S_STD
********************************
Name
====
VIDIOC_G_STD - VIDIOC_S_STD - Query or select the video standard of the current input
Synopsis
========
.. c:function:: int ioctl( int fd, VIDIOC_G_STD, v4l2_std_id *argp )
:name: VIDIOC_G_STD
.. c:function:: int ioctl( int fd, VIDIOC_S_STD, const v4l2_std_id *argp )
:name: VIDIOC_S_STD
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
``argp``
Description
===========
To query and select the current video standard applications use the
:ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a
:ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`
can return a single flag or a set of flags as in struct
:c:type:`v4l2_standard` field ``id``. The flags must be
unambiguous such that they appear in only one enumerated
struct :c:type:`v4l2_standard` structure.
:ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it
does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When
no flags are given or the current input does not support the requested
standard the driver returns an ``EINVAL`` error code. When the standard set
is ambiguous drivers may return ``EINVAL`` or choose any of the requested
standards. If the current input or output does not support standard
video timings (e.g. if :ref:`VIDIOC_ENUMINPUT`
does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is
returned.
Return Value
============
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
The :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable.
ENODATA
Standard video timings are not supported for this input or output.
|
