[andsoitis]

> simple to parse, memory-efficient, and easily implemented on constrained devices

have you considered (compressed) texture formats?

ASTC might very well meet your requirements, including performance on embedded hardware: https://en.wikipedia.org/wiki/Adaptive_scalable_texture_comp...

If not ATSC, also consider ETC and DXT.

[denis_dolya]

ASTC, ETC, and DXT are indeed efficient formats, especially when hardware support is available. In my case, the target devices are microcontrollers without GPUs and with very limited RAM. A software decoder for these formats would require more resources than are realistically available. That is why I am exploring a simpler format that can be implemented with minimal overhead and predictable performance, even on very constrained hardware.