libav is not the successor to ffmpeg. libav is a fork. How'd Debian move so quickly to a(n) (immature) fork?
Politics.
Basically it was a big split down the middle, the entire project split in half.
Not to kick 'em while they're down but it certainly wasn't on technical merit.
As I say to people this is like the Catholic/Protestant split, both sides think they are the one-true-ffmpeg but both have valid claims. Doesn't change the fact it's a disastrous situation and both projects are not in particularly good states.
ffmpeg is the one-true-ffmpeg. If libav surpassed ffmpeg, we'd have libav. The one-true-libav. libav doesn't have a valid claim; It's a fork second to ffmpeg.
Somebody put the cart before the horse. Happy to see it fixed.