Author Archives: Multimedia Mike

Java Multimedia Library

Every so often, a discussion of the Java Multimedia Format (JMF) library pops up on an open source multimedia development list. I had never given it any kind of attention until a Google search recently led me to the documentation. I always assumed that it just supported raw formats and some common, open MPEG formats. It turns out that the library actually supports a few better known codecs, some of which are not completely reverse engineering. Of course, my interest in this would be decompiling them and de-obfuscating them beforehand, as necessary. The library contains a non-obfuscated, pure-Java implementation of the Cinepak codec. It also includes an obfuscated, pure-Java implementation of what I believe are some or all of the MPEG-1 codecs.

However, most interesting codecs (including all of those that are not yet RE’d) are only supported via the Win32 or Linux/Solaris “Performance Packs” which are presumably compiled, SIMD-optimized x86 code.

Some curious features– the pure-Java portion of the library supports some of the quirkier Sound Blaster playback frequencies like 11127 Hz and 22254 Hz (while the performance packs support 8000 Hz -> 48000 Hz). Also, I can not get over the fact that the documentation for the javax.media.format.VideoFormat class states that SMC corresponds to “Sorenson format”. (Here is the SMC format, apparently named for its creator, one Sean M. Callahan.)

PAVC: Palette Tricks

Looking forward to the intercoding portion of this codec, it is very common for palettized graphic animations to use palette tricks to achieve certain graphical effects. One of the most prevalent such uses is screen fades– rather than suddenly showing the entire screen, set all the palette colors to 0 and then draw the graphics. After a certain time delta, adjust the palette to dim colors, wait, set the palette a little brighter, and repeat until the screen is at full color. Perform the inverse process for a fade out effect.

fade-in frame 1
fade-in frame #1

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Trash Music Videos


eMpTyV

I have mirrored an old website of music video reviews called eMpTyV. Seems like an odd thing to do, I know. But if this is the strangest thing you see on the internet, friend, you are not searching hard enough. These reviews seemed to be popular when I mirrored them on another server some time ago and they are back up now. Check them out and have a good laugh at some ridiculous music videos from years past. I particularly enjoy the October 23, 2001 entry for which I supplied the classic 1980s videos.