[duskwuff]

Peeling has been a goal for many audio/video codecs in the past. Nobody's been able to make it work acceptably, though -- either the low-bitrate version sounds awful, or the high-bitrate version increases in size to the point that it might as well just have a low-bitrate version alongside it.

[jagger27]

So in that case you could peel off whichever stream you don’t need, but you waste some upload bandwidth over simply negotiating a bitrate in advance.