I wouldn't recommend this patch as being very safe. Having dealt with ffmpeg, my experience has been that it's ABI is not stable (the .so version number increments often, forcing recompilations). And when trying to update to new lib versions, things sometimes mysteriously break.
Ultimately, FFmpeg is better off as a "built-in" code base. A project wishing to use it should pick a version and include it, and not rely on it externally.