### Post-processing Options:
--extract-audio convert video files to audio-only files (requires
ffmpeg and ffprobe)
- --audio-format FORMAT "best", "aac", "vorbis", "mp3", or "m4a"; best by
- default
+ --audio-format FORMAT "best", "aac", "vorbis", "mp3", "m4a", or "wav";
+ best by default
--audio-quality QUALITY ffmpeg audio bitrate specification, 128k by default
-k, --keep-video keeps the video file on disk after the post-
processing; the video is erased by default