Music to my ears

Yamaha - music of course!

Yamaha has brought two key technologies to the Dreamcast, the Super Intelligent Sound Processor and the GD-ROM. The sound chip is just as good as any of the sound cards on the market today. It offers 64 simultaneous audio channels at 16-bit, 44.1 kHz as well as XG MIDI support. 2MB of RAM is also available for storing both sound effects, and wave table instrument samples.

Gigabyte discs

Far more interesting, is the Gigabyte disc technology, the GD-ROM. Yamaha is essentially using standard multi-session compact disc technology with only minor modifications. The GD-ROM holds 1 gigabyte of data or 120 minutes. There is a low density inner region that's 4 minutes long for about 35 MB of data and an outside high-density area with 112 minutes of space or about ~1 GB. The details of the high-density region really aren't known, but there are two popular hypotheses. The most popular is that the high-density region has minimal error correction information that's even worse than regular CD audio. Support for this can be found with Sega's unusually excessive warnings on their discs "Handle with care. Scratched discs will not play." Unfortunately if that were true, then all of the discs at Hollywood Video would be broken. The other hypothesis is that the data is stored in CAV/CLV format much like laserdiscs.

Dreamcast GD-ROM disc

However Yamaha is accomplishing this feat, the bottom line is that Yamaha has been able to give developers more creative freedom with more space to work with without having worry about increasing the cost of manufacturing their game.

Back of GD-ROM disc