From video to audio file in one request
A video file carries its sound as a separate track. ToolGPT reads that track and writes it into a new audio file in the format you ask for. The picture is simply left out.
MP3 is the safe choice for listening on any phone or player. Choose WAV or FLAC if you plan to edit the sound, because they add no further compression. M4A suits Apple devices and keeps files small.