DVD Forum Chooses MLP for HD-DVD

Meridian Lossless Packing will be mandatory audio format on HD-DVD players

Huntingdon, UK, October 12, 2004–Meridian Audio Limited, the leading consumer electronics manufacturer based in Huntingdon, near Cambridge, England, and developer of Meridian Lossless Packing (MLP), the core technology used in DVD-Audio, the leading high-resolution audio disc format, is pleased to announce that the DVD Forum has selected MLP Lossless technology as mandatory audio standard for HD-DVD, one of the two ‘next generation’ high-definition video disc distribution formats. HD-DVD players will be required to be able to decode at least a 2-channel MLP data stream, making it possible for all HD-DVD discs to offer an MLP soundtrack, in stereo or up to eight channels of 192 kHz audio.

“MLP has the unique ability to embed a lossless downmix from multichannel,” explained Robert Stuart, co-founder of Meridian and co-inventor of MLP. “This downmix can be accessed independently of the multichannel mix or in parallel with it. One very powerful feature of MLP’s downmix method is that it exists in a separate substream, so a relatively simple decoder can recover the 2-channel information. This is unique and unlike any other PCM, lossless or lossy system: the others all have to decode multichannel and then make a downmix.”

The HD-DVD disc specification is expected to allow MLP up to 8 channels at sampling rates up to 192 kHz. It will also mandate that any MLP multichannel stream shall contain a downmix. As a result, content providers will be able to use MLP for the highest quality music and movie sound — an application for which it is ideally suited — knowing that any HD-DVD player will at least be able to replay the stereo downmix, as this is the minimum required specification. Because all players will be required to be able to decode the MLP downmix, therefore, MLP can be used on all titles.

MLP allows a disc to contain more programme material at higher quality — typically employing multiple channels of 24-bit/96 kHz or 24/192 kHz PCM audio data — by compressing multichannel audio data losslessly, in such a way that the player recovers every bit of digital data in the original recording with guaranteed bit-for-bit accuracy: nothing is lost in the encode/decode process. The compression permits longer playing times and additional audio channels where necessary without compromising the audio quality, image quality or video bit-rates.

Although originally employed for music applications, MLP is even more effective at compressing movie soundtracks, where, interestingly, there is less information carried than in music-only environments. MLP can offer up to 4:1 lossless compression, which means that a losslessly compressed soundtrack, bit-for-bit identical to the original audio, can be stored in the same space — or less — than with conventional lossy techniques.

MLP is thus ideal both for audio-only presentations and for soundtracks to accompany high-definition video. In addition, MLP can be used to encode various forms of metadata, allowing the system to expand to encompass new surround-sound modes as they are introduced, including hierarchical formats in which surround playback can be automatically optimised for the capabilities of the replay system.

“MLP delivers the most realistic audio reproduction available on disc,” Stuart concluded. “Making MLP mandatory for audio content on HD-DVD is a major step forward. It gives content providers not only the highest audio quality, but also the greatest flexibility in both audio-only and audio-for-video content, in stereo or surround. At the same time, it offers the viewer and listener at home a bit-for-bit-accurate, digital audio link direct from the studio or soundstage,” he said.

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Meridian Audio Limited is based in Huntingdon, near Cambridge, UK, and was founded in 1977 by Allen Boothroyd and Robert Stuart. With a 25-year history of innovation and development of the highest quality consumer audio systems, the award-winning company is widely recognized as a world leader in digital and analogue audio reproduction. Meridian developed the world’s first audiophile CD player, the world’s first consumer digital surround controller, developed the MLP lossless packing systems mandated for use in DVD-Audio, and is the only UK audio hardware manufacturer to be a member of the DVD Forum. The company’s optical disc players, DSP-based loudspeakers and Digital Theatre systems are unique in the industry, maintaining a super-quality digital audio signal throughout the path from the source to the amplifier, and using digital signal processing to generate advanced crossover characteristics that would be impossible with conventional passive analogue systems. www.meridian-audio.com