There is a codec, little is know about it.
Here are some of its features:
- it codes frame as a three planes
- it employs motion compensation
- it employs old-school vector quantization — fill block, fill block with mask, …
- each value in the stream is coded as the run of values plus actual value coded as several Huffman-coded nibbles (yes, each 4 bits are coded with own Huffman tree) plus sign bit if applicable
- sometimes it performs DCT to restore block content
Try to guess what’s its name.
Hint: MultimediaWiki contains a description of the codec with the similar bitstream reading techniques, which is a relative of this codec.
And, no, since I’m engaged in AAC encoder, I won’t RE nor write decoder for it (at least in the near future).