[donpark]

I don't see anything in what they did that won't work with HEVC or AV1. They just hacked VP8 to be able to save and restore codec state per frame so they can generate multiple versions of the next frame, choosing smaller when network condition is bad. Their innovation is in preventing congestion rather than reacting to the aftermath of congestion.

[mgamache]

Right, they may have used VP8 because VP9 and HEVC are more CPU intensive and they could technically encode more frames per second than the input 60 FPS.

[pishpash]

They probably used it because source code was most available.