January 24th, 2007 by Multimedia Mike
Many thanks to VMware for contributing to the existing MultimediaWiki description for their own VMware Video codec. This is a a lossless codec used for efficiently and losslessly capturing action from virtualized computer desktops running under VMware’s Workstation product. The community had worked out a number of the codec details but VMware people have filled in the gaps.
Posted in Open Source Multimedia | Comments Off on VMware Video Specs
January 15th, 2007 by Multimedia Mike
Sam Hocevar — who I last saw with his groundbreaking counter-CAPTCHA research named PWNtcha — has been working on a fuzzing program called zzuf. Fuzzing is when you create random, implicitly fraudulent data and feed it as input into a program which is supposed to process the data and make sure that the program fails gracefully when chewing on the pathological data. I learned about this technique some time ago and have always wanted to launch it against our body of open source multimedia software. Sam has done just this. None of the multimedia players tested fared particularly well.
FFmpeg devs have already corrected a number of the issues uncovered by this cursory fuzz test. According to the program’s description, zzuf intercepts file operations and changes random bits in the program’s input. This is a great start to the process. However, it will likely only attack the demuxer layer of the various multimedia applications. A deeper method would be to fuzz, e.g., individual chunks of codec data on the way from the demuxer to its corresponding decoder. This could probably be rigged up in FFmpeg fairly easily (just be sure to make the behavior deterministic so any bugs can be reproduced).
Posted in Open Source Multimedia | Comments Off on Fuzzy Sam
January 6th, 2007 by Multimedia Mike
I have embarked on an ambitious new project, with a new blog to match: Gaming Pathology. Remember all those games I have picked up on the cheap so I can study their multimedia? I have managed to amass in excess of 500 games. I decided that this year I would try to play one of them each day. My early focus is on games that are missing data from the MobyGames database. As vast as the database is, I still have at least 80 games out of 500+ that don’t exist in the tables at all. That fact is changing steadily.
Anyway, I thought it would be pertinent to announce the Gaming Pathology blog here since I know that this blog has readers interested in game hacking. Sometimes, my reviews on the new blog include theories or empirical evidence of the underlying technologies, algorithms, and formats that the games use.
And lots of pretty screenshots and videos as well.
Posted in Game Hacking | Comments Off on A Game Each Day
January 5th, 2007 by Multimedia Mike
Karim sends word of a new lossless audio codec under development.
The codec is wryly and appropriately entitled Yet Another Lossless Audio Codec (YALAC) that was originally named TAK. I had that backwards: YALAC was renamed TAK. Obligatory new MultimediaWiki page.
That’s not the most interesting part of Karim’s email. His email notified me of this post which was the first indication I received that there is a entire weblog devoted to lossless audio coding — The Lossless Audio Blog! And I thought this blog was niche. The blog’s sidebar mentions Sony’s ATRAC as being lossless, which I was unaware of (rather, a different variant called ATRAC Advanced Lossless). Also, DTS-HD and Dolby True-HD are listed as lossless codecs.
It’s amazing how much activity there is in the lossless audio codec field. I’ll be keeping an eye on that blog, as should you, the multimedia tech enthusiast.
Posted in Multimedia PressWatch | Comments Off on Lossless Audio Blogging