This site documents XDC (pronounced “ecstasy”) , a video/animation system notable for being able to play full-motion video with synchronized audio on any 1980’s IBM PC/compatible computer with a CGA card.  (For larger files, a hard drive is required; for audio output, a Sound Blaster card is required.)

Basic features of the system:

  • Up to 60 FPS playback, depending on the material and host system.
  • Perfect audio sync.  It is impossible for the audio to drift ahead of or behind the video, regardless of the video framerate or audio samplerate.
  • Color output via the composite color output jack on a CGA card, and B&W output on an attached RGB monitor (simultaneously!).
  • Variable bitrate encoding, with control over the maximum bitrate to adjust size/quality tradeoffs

XDC stands for X86 Delta Compiler, as its method of operation produces executable code for each video frame, as opposed to traditional codecs which output compressed data.  By outputting code instead of data, XDC avoids unnecessary CPU processing normally associated with the load-decompress-translate-update tasks of other codecs.

An earlier version of this system was the basis of the award-winning demo 8088 Domination in 2014.  Here’s video of what that looks like running on an IBM PC/XT with CGA composite output: