8.55. ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL¶
VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL - Enumerate frame intervals
This ioctl lets applications enumerate available frame intervals on a given sub-device pad. Frame intervals only makes sense for sub-devices that can control the frame period on their own. This includes, for instance, image sensors and TV tuners.
For the common use case of image sensors, the frame intervals available on the sub-device output pad depend on the frame format and size on the same pad. Applications must thus specify the desired format and size when enumerating frame intervals.
To enumerate frame intervals applications initialize the
height fields of struct
and call the ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL ioctl with a pointer
to this structure. Drivers fill the rest of the structure or return an
EINVAL error code if one of the input fields is invalid. All frame
intervals are enumerable by beginning at index zero and incrementing by
EINVAL is returned.
Available frame intervals may depend on the current ‘try’ formats at other pads of the sub-device, as well as on the current active links. See ioctl VIDIOC_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT for more information about the try formats.
Sub-devices that support the frame interval enumeration ioctl should implemented it on a single pad only. Its behaviour when supported on multiple pads of the same sub-device is not defined.
||Number of the format in the enumeration, set by the application.|
||Pad number as reported by the media controller API.|
||The media bus format code, as defined in Media Bus Formats.|
||Frame width, in pixels.|
||Frame height, in pixels.|
||Period, in seconds, between consecutive video frames.|
||Frame intervals to be enumerated, from enum v4l2_subdev_format_whence.|
||Reserved for future extensions. Applications and drivers must set the array to zero.|
8.55.5. 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
padreferences a non-existing pad, one of the
heightfields are invalid for the given pad or the
indexfield is out of bounds.