7.56. ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE¶

7.56.1. Name¶

VIDIOC_SUBDEV_ENUM_FRAME_SIZE - Enumerate media bus frame sizes

7.56.2. Synopsis¶

int ioctl(int fd, VIDIOC_SUBDEV_ENUM_FRAME_SIZE, struct v4l2_subdev_frame_size_enum * argp)¶

7.56.3. Arguments¶

fd: File descriptor returned by open().
argp: Pointer to struct v4l2_subdev_frame_size_enum.

7.56.4. Description¶

This ioctl allows applications to enumerate all frame sizes supported by a sub-device on the given pad for the given media bus format. Supported formats can be retrieved with the ioctl VIDIOC_SUBDEV_ENUM_MBUS_CODE ioctl.

To enumerate frame sizes applications initialize the pad, which , code and index fields of the struct v4l2_subdev_mbus_code_enum and call the ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE ioctl with a pointer to the structure. Drivers fill the minimum and maximum frame sizes or return an EINVAL error code if one of the input parameters is invalid.

Sub-devices that only support discrete frame sizes (such as most sensors) will return one or more frame sizes with identical minimum and maximum values.

Not all possible sizes in given [minimum, maximum] ranges need to be supported. For instance, a scaler that uses a fixed-point scaling ratio might not be able to produce every frame size between the minimum and maximum values. Applications must use the VIDIOC_SUBDEV_S_FMT ioctl to try the sub-device for an exact supported frame size.

Available frame sizes may depend on the current ‘try’ formats at other pads of the sub-device, as well as on the current active links and the current values of V4L2 controls. See ioctl VIDIOC_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT for more information about try formats.

v4l2_subdev_frame_size_enum¶

struct v4l2_subdev_frame_size_enum¶
__u32	`index`	Number of the format in the enumeration, set by the application.
__u32	`pad`	Pad number as reported by the media controller API.
__u32	`code`	The media bus format code, as defined in Media Bus Formats.
__u32	`min_width`	Minimum frame width, in pixels.
__u32	`max_width`	Maximum frame width, in pixels.
__u32	`min_height`	Minimum frame height, in pixels.
__u32	`max_height`	Maximum frame height, in pixels.
__u32	`which`	Frame sizes to be enumerated, from enum v4l2_subdev_format_whence.
__u32	`reserved`[8]	Reserved for future extensions. Applications and drivers must set the array to zero.

7.56.5. 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.

EINVAL: The struct v4l2_subdev_frame_size_enum pad references a non-existing pad, the code is invalid for the given pad or the index field is out of bounds.