Archive for September, 2008

A RE Puzzle

Sunday, September 21st, 2008

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).