ERROR: libx264 not found
If you think configure made a mistake, make sure you are using the latest
version from Git. If the latest version fails, report the problem to the
email@example.com mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "ffbuild/config.log" produced by configure as this will help
solve the problem.
sudo apt-get install libx264-dev