I'm still looking for a JPEG 2000 decoder in Rust. There are bindings to C++ decoders, but they have problems.
Someone made a good start on a JPEG 2000 decoder.
They have the header decoding working, but not the content decoding. The author seems to have gone on to other things; I asked. Anyone interested in finishing that?
For reference, here's the core wavelet code in C.. Last year, someone found eight buffer overflows.
I only need decode, only still images, and not for the new "high-throughput" form.
There are C and Java reference implementations available to work from.