- `source`: The preference of the source
- `proto`: Protocol used for download (`https`/`ftps` > `http`/`ftp` > `m3u8_native`/`m3u8` > `http_dash_segments`> `websocket_frag` > `mms`/`rtsp` > `f4f`/`f4m`)
- `vcodec`: Video Codec (`av01` > `vp9.2` > `vp9` > `h265` > `h264` > `vp8` > `h263` > `theora` > other)
- - `acodec`: Audio Codec (`flac`/`alac` > `wav`/`aiff` > `opus` > `vorbis` > `aac` > `mp4a` > `mp3` > `eac3` > `ac3` > `dts` > other)
+ - `acodec`: Audio Codec (`flac`/`alac` > `wav`/`aiff` > `opus` > `vorbis` > `aac` > `mp4a` > `mp3` `ac4` > > `eac3` > `ac3` > `dts` > other)
- `codec`: Equivalent to `vcodec,acodec`
- `vext`: Video Extension (`mp4` > `mov` > `webm` > `flv` > other). If `--prefer-free-formats` is used, `webm` is preferred.
- `aext`: Audio Extension (`m4a` > `aac` > `mp3` > `ogg` > `opus` > `webm` > other). If `--prefer-free-formats` is used, the order changes to `ogg` > `opus` > `webm` > `mp3` > `m4a` > `aac`