avdevice/dshow is a realtime device and as such does not support
seeking. Therefore, its demuxer format should define the
AVFMT_NOBINSEARCH, AVFMT_NOGENSEARCH and AVFMT_NO_BYTE_SEEK flags.
With these flags set, attempting to seek (with, e.g.,
avformat_seek_file()) correctly yields -1 (operation not permitted)
instead of -22 (invalid argument).
This actually seems to apply to many other devices, at least the
gdigrab, v4l2, vfwcap, x11grab, fbdev, kmsgrab and android_camera
devices, from reading the source.
Signed-off-by: Diederick Niehorster <dcnieho@gmail.com>
Reviewed-by: Roger Pack <rogerdpack2@gmail.com>
937de260eb