7.13. ioctl VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS¶
VIDIOC_ENUM_DV_TIMINGS - VIDIOC_SUBDEV_ENUM_DV_TIMINGS - Enumerate supported Digital Video timings
int ioctl(int fd, VIDIOC_ENUM_DV_TIMINGS, struct v4l2_enum_dv_timings *argp)
int ioctl(int fd, VIDIOC_SUBDEV_ENUM_DV_TIMINGS, struct v4l2_enum_dv_timings *argp)
- File descriptor returned by
- Pointer to struct
While some DV receivers or transmitters support a wide range of timings, others support only a limited number of timings. With this ioctl applications can enumerate a list of known supported timings. Call ioctl VIDIOC_DV_TIMINGS_CAP, VIDIOC_SUBDEV_DV_TIMINGS_CAP to check if it also supports other standards or even custom timings that are not in this list.
To query the available timings, applications initialize the
field, set the
pad field to 0, zero the reserved array of struct
v4l2_enum_dv_timings and call the
VIDIOC_ENUM_DV_TIMINGS ioctl on a video node with a pointer to this
structure. Drivers fill the rest of the structure or return an
error code when the index is out of bounds. To enumerate all supported
DV timings, applications shall begin at index zero, incrementing by one
until the driver returns
Drivers may enumerate a different set of DV timings after switching the video input or output.
When implemented by the driver DV timings of subdevices can be queried
by calling the
VIDIOC_SUBDEV_ENUM_DV_TIMINGS ioctl directly on a
subdevice node. The DV timings are specific to inputs (for DV receivers)
or outputs (for DV transmitters), applications must specify the desired
pad number in the struct
Attempts to enumerate timings on a pad that doesn’t support them will
EINVAL error code.
||Number of the DV timings, set by the application.|
||Pad number as reported by the media controller API. This field is only used when operating on a subdevice node. When operating on a video node applications must set this field to zero.|
||Reserved for future extensions. Drivers and applications must set the array to zero.|
7.13.5. 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 struct
indexis out of bounds or the
padnumber is invalid.
- Digital video presets are not supported for this input or output.