How To Convert .mkv and .webm to .mp4 in FFMPEG [MacOSX]

.WEBM to .MP4:
ffmpeg -i FILENAME.webm WHAT\ YOU\ WANT\ TO\ NAME\ FILE.mp4

.MKV to .MP4:
ffmpeg -i FILENAME.mkv -c copy WHAT\ YOU\ WANT\ TO\ NAME\ FILE.mp4


How to convert multiple:
for f in *.webm; do ffmpeg -i "$f" -c:v libx264 -c:a aac -b:a 192k -movflags +faststart "${f%.webm}.mp4"; done

for f in *.mkv; do ffmpeg -i "$f" -c:v libx264 -c:a aac -b:a 192k -movflags +faststart "${f%.mkv}.mp4"; done