If JPEG-XL decompressed faster, I'd use it more. For now, I'm sticking with WEBP for lossless, and AVIF for lossy. AVIF's CDEF filter (directional deringing) works wonders, and it's too bad that JPEG-XL lacks such a filter.

JPEG-XL's lossy modular mode is a very unique feature which needs a lot more exposure than it has. It is well-suited to non-photographic drawings or images that aren't continuous, and have never touched any JPEG-like codecs. It has different kinds of artifacts than what you typically see in a DCT image codec. Rather than ringing, you get slight pixellation.

Yeah, the whole "subscribe to events then check a status result" thing is pretty bad. This is compounded by "Box" behaving differently than everything else. When I made JxlSharp (C# JXL library wrapper), I had to add a workaround in there to force Box to behave like all the other event subscriptions.

And buffer sizes aren't handled in a good way. You have to provide pre-allocated memory, guessing how big it is supposed to be. Then you get a "not big enough" error. This is a guessing game, not a good design. You're forced to overshoot, then shrink the buffer afterwards.

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In different APIs, there tends to be a function you call to get the required buffer size. For example, many Win32 API functions make you call them with a buffer size of 0, then you get the actual required size back. Another possibility is having the library allocate the memory, and return the allocated buffer to you. Since cross-module memory management is hairy (different `malloc` implementations can't interoperate), some APIs let you provide the `malloc`, `realloc`, and `free` functions.

If you wanted better compression, it's called Lossless WEBP. Lossless WEBP is such a nice codec. Compared with Lossless JXL, it decompresses many times more quickly, and while JXL usually produces a smaller file, it doesn't always.

Lossless AVIF is not competitive.

However, lossless WEBP does not support indexed color images. If you need palettes, you're stuck with PNG for now.

I think it's because the SoC hardware is made by Rockchip.