This allows the site to switch quality on the fly (e.g., switching from 720p to 1080p without buffering audio), but it makes downloading difficult. A standard download manager will only download the video file (resulting in a silent movie) or the audio file (resulting in a music file with a black screen).
This write-up explains how the extension works, what "mpmux" is, and why it is necessary for downloading high-quality streams. video downloader professional plus mpmux firefox work
: Capable of saving static videos (MP4, FLV, AVI, etc.) and streaming videos such as m3u8 and blob types. This allows the site to switch quality on the fly (e