[cbhl]

(Disclaimer: This comment is my personal opinion, not that of my employer.)

Really exciting work.

Encoding multiple versions of a video and picking a smaller one in response to congestion already happens for video-on-demand (think YouTube and Netflix videos) in DASH. That said, with VOD you can encode the video slower than real-time.

I can't imagine this ever making it into Skype/FaceTime/Hangouts/Duo. The big corps will probably continue to focus on "more internet" (fiber optic, zero rating, wi-fi hotspots, and internet traffic management practices).

[a-dub]

DASH uses big chunks of operator selectable size though as it is codec agnostic. I wonder if coupling transport and codec could have benefits for the massively scalable VOD case. (ie pre-render a bunch of stuff up front and run a "lite" codec that is coupled to the transport layer and aware of network conditions)

[raggi]

Some of the things you mention already do the multi encode trick and get a resultant bad rep for cpu and battery load.

The real trick is balancing all such product concerns in any next gen.