Name

VIDIOC_QUERYSTD — Sense the video standard received by the current input

Synopsis

int ioctl(int fd,
 int request,
 v4l2_std_id *argp);
 

Arguments

fd

File descriptor returned by open().

request

VIDIOC_QUERYSTD

argp

Description

The hardware may be able to detect the current video standard automatically. To do so, applications call VIDIOC_QUERYSTD with a pointer to a v4l2_std_id type. The driver stores here a set of candidates, this can be a single flag or a set of supported standards if for example the hardware can only distinguish between 50 and 60 Hz systems. When detection is not possible or fails, the set must contain all standards supported by the current video input or output.

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.