Strip audio / subtitle stream with ffmpeg
ls -1 *.mp4 | xargs -I{} ffmpeg -y -i {} -map 0 -map -0:a:0 -c copy /path/to/out/{}
-map -0:a:0 removes the 0th audio stream.
- v - video, such as
-map -0:v - a - audio, such as
-map -0:a - s - subtitles, such as
-map -0:s - d - data, such as
-map -0:d