VIDIOC_OVERLAY — Start or stop video overlay
int ioctl( | int fd, |
| int request, | |
const int *argp); |
This ioctl is part of the video
overlay I/O method. Applications call
VIDIOC_OVERLAY to start or stop the
overlay. It takes a pointer to an integer which must be set to
zero by the application to stop overlay, to one to start.
Drivers do not support VIDIOC_STREAMON or
VIDIOC_STREAMOFF with V4L2_BUF_TYPE_VIDEO_OVERLAY.
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 overlay parameters have not been set up. See the section called “Video Overlay Interface” for the necessary steps.