A STANDARD for squeezing more music onto CDs and DVDs is under threat of
legal action from a company backed by Steven Spielberg. The company, Digital
Theater Systems (DTS), claims that the Japanese-based DVD Forum used 鈥渋mproper
and false assumptions, procedures and information鈥� when it rejected DTS鈥檚
recording system in favour of a British one that is licensed to DTS鈥檚 rival,
Dolby Labs.
Record companies in the DVD Forum want any successor to the CD to store at
least 74 minutes of high-quality six-channel surround sound. Even DVD cannot do
this unless the digital code is compressed. Existing systems, including the DTS
system, are 鈥渓ossy鈥�: they throw away sound which the ear should not notice.
However, the record industry is not convinced, and prefers that any recording
system used for audio should be lossless
(鈥淛ust listen to this鈥�, New 杏吧原创, 18 October 1997, p 44).
In 1996, the late Oxford mathematician Michael Gerzon joined with audio
developer Peter Craven to patent a compression system which packs audio code
without loss. Meridian Lossless Packing (MLP) was licensed to Dolby.
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Data-compression systems for PC text data are lossless, but they do not
compress audio very effectively. Gerzon realised that an audio waveform can be
predicted quite accurately, and that this can be used to reduce the number of
bits needed to record it. Independent tests for the DVD Forum found that MLP
extends DVD-Audio playing time to 89 minutes for 6-channel surround-sound and
230 minutes for stereo.
This met the record companies鈥� requirements, so lossless MLP was adopted by
the DVD Forum.