Ffmpeg is good software to convert formats for video and audio. This article is going to show you how to do batch conversion.
Example 1:
for f in *.ape; do ffmpeg -i "$f" "$( sed -e 's/\.ape/.flac/g' <<< $f )"; done
The Example 1 is to convert all ape files into flac files in a folder. This example is very simple, because there is nothing to do with either ape or flac. They are both lossless.
Example 2:
for f in *.mpeg; do ffmpeg -i "$f" -c:v libvpx -b:v 1800K -c:a libvorbis -b:a 192K "$( sed -e 's/\.mpeg/.webm/g' <<< $f )"; done
Example 2 is more complicated. They are lossy format, so in order to control their quality and size, we added some parameters -c:v libvpx -b:v 1800K -c:a libvorbis -b:a 192K for them. If we need even more parameters, we can just add them between for f in *.mpeg; do ffmpeg -i "$f" and "$( sed -e 's/.mpeg/.webm/g' <<< $f )"; done
Have fun; be free.