[nwallin]

> AV1 software decoding is already very intensive

I think you might be misunderestimating how incredible the dav1d AV1 decoder is. Not only does it require less total time than the reference decoder to decode the same video, but it can spread that out over far more threads. I was unable to watch 4k 60fps av1 video on my media center PC (it's from 2019, so predates hardware av1 decoding, and, well, the CPU was a little long in the tooth) until I switched to dav1d. With dav1d I am now able to watch 4k 60fps av1 using software decoding, and my machine uses 10% CPU while doing so. Really amazing piece of software.

With any luck, the dav2d 5x claim will hold true, and 10% CPU usage will scale to 50% CPU usage, meaning I'm still able to watch 4k 60fps video on my media center without a hardware upgrade. (that machine doesn't have hyperthreading, so 50% cpu is actually 50%, not 100% in a fancy suit)

[rbultje]

dav2d author here - the 5x number is just where we currently are, it's not the theoretical limit. We're hopeful that a significant amount of the increase we observe in dav2d relative to dav1d is in math code, which should be easier to optimize using hand-written assembly or other algorithmic optimizations. If that holds true, the practical slowdown once everything has been optimized may be substantially less, possibly 2x.