$20K Bounty Offered for Optimizing Rust Code in Rav1d AV1 Decoder

Summary

In March of 2023 we announced that we were starting work on a safer high performance AV1 decoder called rav1d, written in Rust. We partnered with Immunant to do the engineering work. By September of 2024 rav1d was basically complete and we learned a lot during the process. Today rav1d works well—it passes all the same tests as the dav1d decoder it is based on, which is written in C. It’s possible to build and run Chromium with it.There’s just one problem—it’s not quite as fast as the C version. We want to change that and we need your help.Our Rust-based rav1d decoder is currently about 5% slower than the C-based dav1d decoder (the exact amount differs a bit depending on the benchmark, input, and platform). This is enough of a difference to be a problem for potential adopters, and, frankly, it just bothers us. The development team worked hard to get it to performance parity. We brought in a couple of other contractors who have experience with optimizing things like this. We wrote about the optimization work we did. However, we were still unable to get to performance parity and, to be frank again, we aren’t really sure what to do next.After racking our brains for options, we decided to offer a bounty pool of $20,000 for getting rav1d to performance parity with dav1d. Hopefully folks out there can help get rav1d performance advanced to where it needs to be, and ideally we and the Rust community will also learn something about how Rust performance stacks up against C.The official rules are here, but to summarize:The contest is open to individuals or teams of individuals who are legal residents or citizens of the United States, United Kingdom, European Union, Canada, New Zealand, or Australia.The rules provide instructions for benchmarking performance improvements.You work on improving performance. Your improvements can be in rav1d, the Rust compiler, or the Rust standard library.The dav1d and rav1d decoders share the exact same low-level assembly code optimizations—you ...