The friction isn't in the movement of code, it's in the movement of ideas and prioritization. Adding functionality, cleaning up the code, etc. When a project's

The friction isn't in the movement of code, it's in the movement of ideas and prioritization. Adding functionality, cleaning up the code, etc. When a project's contributors disagree substantially on how a project should be run, where the priorities should be, etc. then there can be a significant amount of friction just in day to day operations (like communicating about ideas on the mailing list). Perhaps some of the fixes from libav can be brought back into ffmpeg, but eventually people will want to standardize on one or the other, and if the libav folks are splitting off because they want improvement, revitalization, etc. and the old guard doesn't, then I suspect people will move to libav instead. Similar issues happened in the past with xorg (where XFree86 was mismanaged and eventually the community had enough and decided to fork it and fix it) and with KHTML/WebKit (where Apple forked it and made so many improvements to it that WebCore/JavaScriptCore have replaced KHTML in most (all?) projects (including Qt). That split wasn't a philosophical/managerial split, mind you, but the end result was the same.