Not sure why this is being posted now, but, libav development has been abandoned since 2018.

By far the most damaging fallout of this was the demonstration of how much power Debian package maintainers have. The Debian ffmpeg package, for a while, printed the "error":

  *** THIS PROGRAM IS DEPRECATED ***
  This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.

No part of this was true, and Debian eventually dropped avconv in Stretch/9. but that this falsehood was allowed to stay in the package for so long really left a bad taste in my mouth about Debian is run.