DVD-Audio Specification Finalized - Meridian's MLP Incorporated In DVD-Audio Specifications
0n February 8, 1999 in Tokyo, the Steering Committee of the DVD Forum gave their approval to the specification for DVD-Audio, incorporating Meridian Lossless Packing (MLP). DVD-Audio is the latest and perhaps most exciting of the DVD family which includes DVD-Video, DVD-ROM, DVD-RAM and DVD-R. The DVD-Audio specification is the product of a process of international technical co-operation in Working Group 4 (WG-4) of the DVD Forum (www.dvdforum.org). Through extraordinary cooperation with the International Steering Committee (ISC), representing the worldwide recording industry, WG-4was able to meet most of the requirements of the music industry while including many- technical innovations. DVD-Audio exploits a data capacity seven times larger than CD, providing music in surround sound and with much higher resolution and dynamic range. The ISC's I3-point list of requirements included the ability to offer playing times of at least 74 minutes of the highest quality surround sound on the disc. To achieve this, a method of harmlessly compressing the audio data on the disc was-needed and MLP was selected amid international competition. MLP Background MLP is an audio coding scheme using proprietary technology, which has been developed over three years by Meridian Audio and its associates. There are already several well known perceptual or lossy data reduction coding methods like MPEG and Dolby Digital, both of which are used on the DVD-Video disc to provide about 135 minutes of motion picture playing time per layer. These schemes operate by discarding information that is determined to be less important to the listener. DTS Coherent Acoustics is another perceptual coding scheme that is much less aggressive in discarding information and operates whenever possible in a lossless mode. MLP does not incorporate perceptual coding. MLP is purely lossless. MLP coding does not alter the final decoded signal in any way; it ""packs"" the audio data more efficiently into a smaller data rate for transmission and carries it in a protected environment along with associated data. MLP is a decoding method optimized for demands of the very highest quality sound. MLP has been optimized to open new opportunities for multichannel and for audio at high sample rates with very high precision. Now that it is mandated for DVD-Audio, Meridian is sure that MLP will find many other applications. Examples include uses in movie studios for storing and transmitting sound, for holding the original location recordings for music, in news gathering, for archiving and anywhere else that audio data is stored, including of course the rapidly growing applications on personal computers and the Internet. Soon every PC will need to decode MLP, assuming PC will incorporate DVD-Audio capability. Previously, the highest quality sound came with Linear PCM coding and the DVD-Audio format uses LPCM but at higher resolution operation. Unfortunately: PCM distribution formats do not require the mastering or playback process to be lossless - so data can be subtly changed on the way through the production chain. MLP is a true lossless system. The original data is delivered bit-for-bit at playback. It even has a method of confirming that the whole chain is lossless. This means that for the first time the listener can be sure of hearing exactly what the producer intended bit-for-bit, note for-note. There is no need for elaborate listening tests to qualify this coding system - it guarantees delivery of the original recording, efficiently over a number of carriers, archives and computing platforms. How Did A Small UK Company Get Selected? Although a minnow by the standards of other members of WG-4, Meridian Audio has a superior reputation in the world of high-end audio, earned through making leading-edge no-compromise digital audio products for the home music lover. Meridian is also the only high-end audio manufacturer represented in WG-4. Meridian's Chairman, Robert Stuart, is renowned in audio circles for his expertise in the fields of audio coding and psychoacoustics. Mr. Stuart also chairs a surround sound advocacy group called Acoustic Renaissance for Audio (ARA), which made a proposal to the DVD Forum members in 1994 on how a high-quality audio disc could be designed. The organizationís Web side is www.meridian-audio.com/ara The competition to select a lossless coding system for DVD-Audio took place during 1998 and was a fiercely fought battle between proponents from Japan, Korea, the UK and the USA. MLP was selected because it was the best performer technically, showing particular strengths in the amount and reliability of compression, in controlling data rate, and by having unique features that were able to enhance DVD-Audio's ability to handle multichannel and stereo simultaneously. MLP was also considered the maturest technology, having been speculatively developed over three years by Meridian. MLP was particularly championed by the music industry because it offered such a wide range of production features and high-quality protection features that appealed directly to content providers. MLP And Dolby In an agreement announced in June 1998, Dolby Laboratories (San Francisco, California) agreed to handle the licensing of MLP. MLP is being offered to makers of integrated circuits, recording equipment, CD and DVD players, and audio decoders and also for use in transmission, storage and archive. At this point ten major chipmakers are working on MLP implementations. Dolby is a member of WG-4 and was able to offer significant support to Meridian during the selection and specification process. DVD-Audio Highlights DVD-Audio supports: a wide range of digital audio options: PCM and MLP decoding - mandatory for all players. Discs may use either on a track-by-track: basis. Sampling frequencies may include 48 kHz, 96 kHz, 192 kHz, and 44.1 kHz, 88.2:kHz, 176.4 kHz. DVD-Audio can have bit resolution of 16-, 20-, or 24-bit. With MLP the precision may be selected between 16 and 24 bits in 1-bit steps. Up to six channels are available for multichannel recording with a transfer rate of 9.6 Mbps and many provisions for providing 2-channel and multichannel mixes. In 2-channel stereo, more than 74 minutes (PCM) or 120 minutes (PCM/MLP) playing time is possible on a single-sided/single-layer disc at the highest quality mode at 192 kHz/24-bit. For multichannel, a 96kHz 24-bit 6-channel recording can be included with more than 80 minutes of playback time. The signal is said to have an immediate presence like that of an actual concert hall or an entirely new, high-quality three-dimensional surround sound environment. DVD-Audio content recorded in multichannel mode can also be played back properly on 2-channel stereo systems as intended by studio producers as a result of the dedicated content producer-directed fold-down capability. DVD-Audio supports playback of video clips with the quality of the DVD-Video format. Video slide shows can also be included for viewing while listening to high-quality music. Discs can contain information of interest to music fans, including visual display of liner notes, score, album title, song titles, discography and a URL for access to bonus contents on the Web. For more information contact Wes Phillips at J.B. Stanton Communications, Inc., 860 542 1234 or email: wesp@ibstanton.com.