[sharifhsn]

The tests are the real clincher here. That’s the main reason that this project has made so much progress: the FATE suite highlights specific bugs to fix and tracks regressions.

As for optimization, that seems to be more of a question of effort than whether it’s possible. I was able to take down the performance gap on Rust vs C (without Assembly) from 10x to 1.5x through detailed profiling and iterative improvements with Claude.

It also looks like the Anthropic C compiler was built from scratch. By contrast, `wedeo` was directly based on FFmpeg’s existing code. Going by spec and test suite only would have taken a lot longer, and the quality would have been significantly lower.

[jdiff]

Anthropic's C compiler also had an incredible test suite available, and was trained on compiler codebases. It might have been built "from scratch" but compilers are incredibly well-trodden ground.

And to contrast, Cursor's browser explicitly reviewed Servo's architecture before setting out, and still wound up like that.

[sharifhsn]

The difference between using general knowledge and summaries and doing code-for-code rewrites cannot be understated. When creating `wedeo`, despite DIRECTLY reviewing FFmpeg's code, Claude would frequently make mistakes that would have to be fixed. I would constantly have it go and refer back to the ground truth FFmpeg source implementation. It did eventually work, but only after several rounds of reviews, and often dead-end investigations. Being able to directly inspect (and in some cases modify for extra debug output) FFmpeg at any given time was invaluable, and I doubt any rewrite would succeed without having that.