1 .. -*- coding: utf-8; mode: rst -*-
5 ********************************
6 ioctl VIDIOC_G_STD, VIDIOC_S_STD
7 ********************************
12 VIDIOC_G_STD - VIDIOC_S_STD - Query or select the video standard of the current input
18 .. c:function:: int ioctl( int fd, VIDIOC_G_STD, v4l2_std_id *argp )
21 .. c:function:: int ioctl( int fd, VIDIOC_S_STD, const v4l2_std_id *argp )
29 File descriptor returned by :ref:`open() <func-open>`.
37 To query and select the current video standard applications use the
38 :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a
39 :ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`
40 can return a single flag or a set of flags as in struct
41 :c:type:`v4l2_standard` field ``id``. The flags must be
42 unambiguous such that they appear in only one enumerated
43 struct :c:type:`v4l2_standard` structure.
45 :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it
46 does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When
47 no flags are given or the current input does not support the requested
48 standard the driver returns an ``EINVAL`` error code. When the standard set
49 is ambiguous drivers may return ``EINVAL`` or choose any of the requested
50 standards. If the current input or output does not support standard
51 video timings (e.g. if :ref:`VIDIOC_ENUMINPUT`
52 does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is
59 On success 0 is returned, on error -1 and the ``errno`` variable is set
60 appropriately. The generic error codes are described at the
61 :ref:`Generic Error Codes <gen-errors>` chapter.
64 The :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable.
67 Standard video timings are not supported for this input or output.