Then what's the "high quality" video? Anyone can use the web interface of youtube and watch it without any DRM (for now). Why are they so jellously guarding one specific API when the others are wide open?
It's the VP9 high bitrate codec, to get it you need the cookie from a premium subscribed account or yt-dlp can get it by default by emulating an iPhone header if I recall correctly.
--extractor-args "youtube:player_client=default,ios"
But this is done by default.
As somewhat related know that there's also a higher bitrate OPUS codec that's only available to premium cookies, it would then be the default YouTube music codec.
