Used to make comb artifacts for videotestsrc pattern=ball for YUY2 format only (not AYUV). Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1938>
It was different compared to the corresponding part in both ffmpeg and the asm implementation. Fixing this makes videotestsrc pattern=spokes not jump at all when not using the asm optimisations. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1816>