If you may get an error while install/configure ffmpeg packages
yasm/nasm not found or too old. Use --disable-yasm for a crippled build.
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
firstname.lastname@example.org mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "config.log" produced by configure as this will help
solve the problem.
You need to install yasm on your system by yum command,