I want videos on the web to have an audio-only mode

[WebWeWantBot]

When people use video platforms to listen to music, chances are they don't look at the video, but their browser does download it. On a large scale, this probably has environmental impact: it wastes energy consumption.

What if there was a way for browsers to only stream audio, for instance when the user choose so, and automatically when the user is not looking at the tab where the video stream is happening?

Maybe it could be realized through an update to the video-element to allow for providing an audio-only source, which video platforms could then use.

[cwilso]

You can actually already do this for a given page by using media fallbacks with <video> elements. It might be useful to have a specific "prefer audio only" setting in the user agent; but that might easily go awry.

However, it's actually not really possible to do this without involving the back end media server setup - because the usual video format may be (probably IS) interleaved chunks of video and audio, and ideally you'd want to tell it to only send audio format, and it may not be configured to do that today.