CompuServe Messages

CD-ROM XA is an Addendum to the Yellow Book Standard (CD-ROM) which defines streaming, interleaved data with audio compression (ADPCM). Essentially a CD-ROM XA stream consists of compressed audio (ADPCM) and "other" data which are interleaved (one sector after another) in a continuous stream. The major advantages of CD-ROM XA streaming data are: 1) Audio and "other" data (video, etc.) arrive at the computer in synchronized form. As a result much better synchronication (talking heads, etc.) is available than with regular CD-ROM, where separate "files" of information are loaded into RAM, then synchronized by the CPU. It is kind of like the difference between a city street, with stop and go traffic and stoplights – and a freeway with onramps and offramps – a big difference in throughput. 2) Lots of multi-channel high quality audio is available (up to 18 hours on a single CD-ROM XA disc). 3) Because the XA circuitry does the deleaving and audio decompression, the CPU of the host is not burdened. This means higher performance, and MUCH lower needs for buffering, either in RAM or on hard disk. This in turn means that CD-ROM XA brings quality multimedia to low end platforms. 4) Because CD-ROM XA uses Mode Two, Form Two of the CD-ROM standard, it provides higher effective bandwidth (173 KB/sec vs 157 KB/sec) than regular CD-ROM. The major difference is in not having robust error correction, as much higher bit error rates can be tolerated in multimedia data than in say financial data or executable code. The result is better quality and higher performace from CD-ROM XA than from CD-ROM. For the above reasons, CD-ROM XA has been embraced by Apple, Hitachi, IBM, JVC, Kodak, Microsoft, Nintendo, Philips, Sony, 3DO, Toshiba – and more to come. We feel that it has the potential to be the cross-platform standard for multimedia publishing in the future. Our company, Mammoth Micro Productions, is expert in CD-ROM XA. We would be happy to provide further information on the subject. We also have a set of professional stream creation tools on the market – currently being distributed in the United States by IBM and Sony. For further information contact: Dan Kennedy Mammoth Micro Productions, Inc. 1700 Westlake Avenue North, Suite 702 Seattle, WA 98109 (206) 281-7500 (206) 281-7734 FAX