ffmpeg: Remove audio from several videos while preserving quality

To create audio-less copies of all the .mp4 videos in a folder, execute the following:

find . -type f -name "*.mp4" -exec bash -c 'FILE="$1"; ffmpeg -i "${FILE}" -c copy -an "${FILE%.mp4}.ns.mp4";' _ '{}' \;

For a single file, the command would be:

ffmpeg -i input.mp4 -c copy -an output.mp4