This screams for proper release notes. The official ones are pretty light (http://git.videolan.org/gitweb.cgi/ffmpeg.git/?p=ffmpeg.git;... ), and refer to the Changelog (http://git.videolan.org/gitweb.cgi/ffmpeg.git/?p=ffmpeg.git;... ) which is quite terse. Phoronix did some reformatting of the changelog, it's a bit easier to read:

http://www.phoronix.com/scan.php?page=news_item&px=FFmpeg-3....

But honestly this type of stuff should be done by the project before any release.