ffmpeg is an open source command-line tool that enables us to convert audio or video formats.

-an option disables audio recording.
You can remove audio from movie:

$ ffmpeg -i example.mp4 -an example-nosound.mp4

Beside, an instant one-liner program to process multiple files with fish shell is like this:

$ for x in ./*.mp4; ffmpeg -i $x -an $x.no-sound.mp4; end