ffmpeg: Add valid values of AVDiscard
skip-frame
is currently wired up to ffmpeg's skip_frames
which is the enum AVDiscard
here: https://ffmpeg.org/doxygen/trunk/group__lavc__decoding.html#ga352363bce7d3ed82c101b3bc001d1c16
However, none of the values of skip-frame
actually correspond to any values that ffmpeg accepts. Maybe this was a legacy thing? In any case, this PR wires up the AVDiscard
values through gst-libav.