Thank you. I'm currently using mozjpeg-sys as well as a C shim to the libjpeg API, but even with the error handler in C the setjmp/longjmp behavior leads to horrible-to-debug problems.
I personally think it's time for a better (Rust) codec for jpeg decoding and encoding. I'd love to see it be fast enough for Firefox.
@niklaas I'd love to see what you have! A nom-based parser might be better for a pull design.