ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL
&manvol;
VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL
Enumerate frame intervals
int ioctl
int fd
int request
struct v4l2_subdev_frame_interval_enum *
argp
Arguments
fd
&fd;
request
VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL
argp
Description
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
index, pad,
which, code,
width and height
fields of &v4l2-subdev-frame-interval-enum; and call the
VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL ioctl with a pointer
to this structure. Drivers fill the rest of the structure or return
an &EINVAL; if one of the input fields is invalid. All frame intervals are
enumerable by beginning at index zero and incrementing by one until
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
&VIDIOC-SUBDEV-G-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.
struct v4l2_subdev_frame_interval_enum
&cs-str;
__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
.
__u32
width
Frame width, in pixels.
__u32
height
Frame height, in pixels.
&v4l2-fract;
interval
Period, in seconds, between consecutive video frames.
__u32
which
Frame intervals to be enumerated, from &v4l2-subdev-format-whence;.
__u32
reserved[8]
Reserved for future extensions. Applications and drivers must
set the array to zero.
&return-value;
EINVAL
The &v4l2-subdev-frame-interval-enum;
pad references a non-existing pad, one of
the code, width
or height fields are invalid for the given
pad or the index field is out of bounds.