> most of the libavcodec and libavformat work has been done in libav
Well, I believe this is a bit more complex. While it might be true for API changes and cleanups, FFmpeg has dozens of additionnal codecs and formats, as well as way more assembly/optimization code.
> What you should know is that the current codebase of FFmpeg is a huge mess compared to libav
Honestly, this is pure FUD and it's very surprising to read that from you. You seem to have no idea about the cleanups of FFmpeg because we do not advertise them (they are not relevant for the users). What is so much a huge mess? This is very insulting for the work done by FFmpeg developers these last years. Hey, even libmpcodecs (the MPlayer filter wrapper) is no more. A lot of work was also done on the documentation. Seriously, please stop doing FUD like this.
> Choosing one or the other gives you different set of features
Not exactly true.