I use this in combination with https://addons.mozilla.org/en-US/firefox/addon/send-to-mpv-p... as my pimary way to play video content on the web. It's nice having everything play in a consistent player with consistent controls as well as tons of useful features.
Or if you want to play something without video at all for e.g. music livestreams, that can be done too. Example below uses the famous lofi girl stream.
Maybe that behavior is Linux-exclusive? Under macOS and Windows, if I only use --ytdl-format='bestaudio/best' with livestreams mpv will spawn a window with the video.
I'm on Windows as well. Just get rid of the 'best' argument for '--ytdl-format'. Also, 'bestaudio' is mostly only known as a keyword for Youtube videos.
It can also use SDL or DRM to render video on the console. I use this for viewing video and images (even pdfs, with imagemagick) without a graphical environment.
Shove that into ~/.config/mpv/mpv.conf (each parameter on its own line and without the dash prefix) if you don't want to repeat yourself over and over again.
For some reason hwdec doesn't seem to make much difference for me in terms of power or CPU usage. Also worth mentioning is profile=gpu-hq (can just uncomment in the example config).
I recommend this for watching lectures & other long videos. Compared to the web player mpv gives finer control of playback speed and seeking forwards and backwards.
Really great for studying other languages too. Can quickly go back and relisten to the same section over and over and over again without an ad popping in midway through a listen.