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