Comment by cogman10

I'm not claiming that software will be more efficient. I'm claiming that things that make it easy to go fast in hardware make it easy to go fast in software.

Bit masking/shifting is certainly more expensive in software, but it's also about the cheapest software operation. In most cases it's a single cycle transform. In the best cases, it's something that can be done with some type of SIMD instruction. And in even better cases, it's a repeated operation which can be distributed across the array of GPU vector processors.

What kills both hardware and software performance is data dependency and conditional logic. That's the sort of thing that was limited in the AV1 stream.