I just wanted to draw attention to a recent effort by one Michael Sabin who has been building a Java application called jPSXdec to play back videos ripped from the Sony PlayStation 1.

To review, the original PlayStation had a bit of dedicated hardware called the motion decoder (MDEC) which decoded specially formatted blocks of what were essentially motion JPEG data. Assorted games also compressed the blocks using Huffman codes which were decoded by software. While the MDEC hardware was rigid in the data it would accept, PS programmers could deploy whatever Huffman tables they chose. I always thought it would be an interesting project (and a natural extension of my usual efforts) to catalog the various tables needed to play movies from different games, as well as different strategies that games have used to store the data on the disc.

Michael S. has been doing just that. There is a blog to document jPSXdec’s progress. Near and dear to my heart, however, is the fact that he is building a remarkable document (seen in the project’s download list) that explains precisely how to decode this data, from the perspective of a non-multimedia geek, no less.