FFMPEG: Convert multiple files using xargs

I stumbled upon this post (Google cache link) when I was trying to process multiple files via xargs.

ls *.webm | xargs -I % ffmpeg -i % %.m4a

The key part of this one-liner is xargs -i %. This means that each line of STDIN passed to xargs is put into a variable and can be referenced as %. Hence, the following text which specifies ffmpeg -i x.webm x.m4a to make it convert.