Comment by xnx
2 days ago
> This consolidates JPEG XL’s position as the best image codec currently available, for both lossless and lossy compression, across the quality range but in particular for high quality to visually lossless quality. It is Pareto-optimal across a wide range of speed settings.
Wow. Nice. Big improvement if JPEG and PNG can be replaced by one codec.
And even better if someone can implement the whole massive spec securely...
Disclaimer: As a manager I led the JPEG XL design, implementation and standardization effort at Google, and as an IC I was responsible for lossy format, encoding heuristics and image quality.
JPEG XL is not that massive.
JPEG XL spec is slightly less than 100 pages, about half the size of the JPEG1 spec.
A simple implementation in j40 was around 7000 lines of code last time I looked, not sure if it is 100 % complete however.
A simple encoder at libjxl-tiny is of similar size and very attractive to be used for expressing similar coding decisions in hardware intended for digital cameras.
A complex speed optimized C++ decoder implementation is ~35000 lines of code, but much of it is not due to the spec, but getting most out of SIMD-powered multi-core computers.
The binary size increase in Chromium on arm for adding (in the past) the C++ decoder was around 200 kB in APK size, possibly around 0.1 %.
This is probably impossible and also not needed. Choose security through compartmentalization (instead of security through correctness that never works), if you really care about security.
Works for me with Qubes OS.
Do you daily drive Qubes? I'd be curious to hear about your experiences. I've been following the project from the sidelines for years, but haven't taken the leap.
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Qubes doesn't compartmentalize the image decoder in a web browser from the rest of the renderer, and if you're serving tracking pixels and can exploit image decoding, you can make serious mischief.
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The part I'm more excited for is all the image-like/bundle of image like data that until Jpeg-xl didn't have any good codecs (usually implemented as folders of images). One clear example of this is PBR in blender and friends. (e.g. a combo of normal map, roughness, color, metalness etc)
This is new to me. Can you elaborate please? Perhaps a link to somewhere showcasing this (and contrasting this to other solutions).
See https://devtalk.blender.org/t/jpeg-xl-as-an-intermediate-for.... TLDR is that one of the really interesting things JPEG-XL adds is the ability to have an arbitrary number of non-color channels. The current solution is generally to use separate grayscale images for each extra thing you want to store, which is inefficient since it loses the ability to compress the correlation between the separate channels. Another example usecase would be capturing images at 10 different wavelengths rather than the typical RGB.
> Big improvement if JPEG and PNG can be replaced by one codec.
By one ? Ten maybe: webp, avif, ...