I just did a test compile on 10.04 and it worked. Note that first I deleted the old ~/ffmpeg directory because it was using SVN and FFmpeg has moved to Git.
If you --enable-shared on FFmpeg, then you should do the same for the external libraries. Add it to x264 and libvpx. For LAME just remove --disable-shared.
Then after you install everything you should run "sudo ldconfig". If you don't run that command you'll receive something like the following:
Code:$ ffmpeg ffmpeg: error while loading shared libraries: libavdevice.so.52: cannot open shared object file: No such file or directory