$20,000 rav1d AV1 Decoder Performance Bounty

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:

1. 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.
2. The rules provide instructions for benchmarking performance improvements.
3. You work on improving performance. Your improvements can be in rav1d, the Rust compiler, or the Rust standard library.
4. The dav1d and rav1d decoders share the exact same low-level assembly code optimizations—you cannot modify this assembly. You must improve the Rust code (or the Rust compiler), which is what differs between dav1d and rav1d. You may not introduce code into rav1d in a language other than Rust. We encourage you to ask questions early on in issues or by emailing us so as to avoid investing heavily in something that might not be eligible!
5. Get your performance improvements merged into the relevant project per the project's standard contribution process and under its open source license(s), then email us per the instructions in the official rules to enter and potentially be rewarded for your contribution.
6. When the contest ends (likely either because we met our goal or time has run out) we will, at our discretion, divide the bounty proportionally between the largest contributors to performance gains.

At the end of the day, we reserve the right to award the money to the person(s) or team(s) that we deem to have helped us reach or exceed performance parity in the best possible way.

If we update the rules we'll post a note here and on the official rules page.

Good luck! Have fun!