Comment by JyrkiAlakuijala

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 %.