7.41. ioctl VIDIOC_G_STD, VIDIOC_S_STD, VIDIOC_SUBDEV_G_STD, VIDIOC_SUBDEV_S_STD¶
VIDIOC_G_STD - VIDIOC_S_STD - VIDIOC_SUBDEV_G_STD - VIDIOC_SUBDEV_S_STD - Query or select the video standard of the current input
To query and select the current video standard applications use the
VIDIOC_G_STD and VIDIOC_S_STD ioctls which take a pointer to a
v4l2_std_id type as argument. VIDIOC_G_STD
can return a single flag or a set of flags as in struct
id. The flags must be
unambiguous such that they appear in only one enumerated
VIDIOC_S_STD accepts one or more flags, being a write-only ioctl it
does not return the actual new standard as 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 ioctl VIDIOC_ENUMINPUT
does not set the
V4L2_IN_CAP_STD flag), then
ENODATA error code is
VIDIOC_SUBDEV_S_STD on a subdev device node that has been registered
in read-only mode is not allowed. An error is returned and the errno variable is
7.41.5. 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
Generic Error Codes chapter.
- The VIDIOC_S_STD parameter was unsuitable.
- Standard video timings are not supported for this input or output.
VIDIOC_SUBDEV_S_STDhas been called on a read-only subdevice.