(luckily there’s not much left of this month of intermediate codecs)
So I’ve looked at another intermediate codec, post title hints on both its name and design. Coding scheme is rather simple: you code lines either in raw form or with prediction (from the left neighbour for the top line or (3 * L + 3 * T - 2 * TL) >> 2 for other lines, prediction error is coded with fixed Huffman codes.
Simple, right?
Here’s the catch: there is an insane number of formats it supports, both for storage and output and there’s an insane number of decoding functions for decoding format X into format Y.
So quite probably no decoder — not interesting and too tedious.