Improving performance of rav1d video decoder

All being equal codecs ought to be in WUFFS† rather than Rust, but I can well imagine that it's a much bigger lift to take something as complicated as dav1d and write the analogous WUFFS than to clean up the c2rust translation, if you said a thousand times harder I'd have no trouble believing that. I just think it's worth it for us as a civilisation.

† Or an equivalent special purpose language, but WUFFS is right there

WUFFS would be great for parsing container files (Matroska, webm, mp4) but it does not seem at all suitable for a video decoder. Without dynamic memory allocation it would be challenging to deal with dynamic data. Video codecs are not simply parsing a file to get the data, they require quite a bit of very dynamic state to be managed.

Requiring dynamic state seems not obvious to me. At the end of the day you have a fixed number of pixels on the screen. If every single pixel changes from frame to frame that should constitute the most work your codec has to do, no? I'm not a codec writer but that's my intuition based on the assumption that codecs are basically designed to minimize the amount of 'work' being done from frame to frame.