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All about DVD Audio
A quick guide to this high definition music format
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by: Carol Mazur
DVD-Audio is a music format that has the potential to greatly enhance the quality of music reproduced in our homes. It offers improved resolution listening over conventional compact disc music systems in stereo or two-channel mode or in multi-channel format such as a surround sound system with its sic channels of sound.
Since the benefits of the DVD-Video format feature digital sound very highly, DVD-Audio seems like a logical extension of the technology. Manufacturers of consumer electronics equipment have already introduced a number of hardware products that support DVD Audio, while the software support is slowly taking shape.
DVD-Audio is making wide inroads into domestic home theatre systems, computer systems and in-car sound products. The DVD medium offers the potential of superior performance over CD because its capacity to store digital information is much greater. It allows greater freedom in the way sound information can be retrieved or replayed too.
Compared to the conventional CD format which, DVD-Audio has a much higher specification. DVD-Audio uses a two-channel sampling rate of 192kHz (CD is 44.1kHz). DVD-Audio digital information is transferred with up to 24-bit resolution (compared to 16-bit CD capacity). The result is the capacity for better sound quality in terms of resolution, dynamic content, detail, clarity, information separation, sound staging and other subjective listening aspects.
DVD-Audio can also be engineered to be retrieved and played in two, four, five, or six-channel configurations and each track can be encoded to play in a different way. This means that the first track can be in two-channel 96KHz sound, track two in six-channel 48KHz sound and tracks three and four in four-speaker 48KHz sound. There could be as many as twenty combinations of channel sound recording and replay.
A new technology called Packed PCM effectively doubles the amount of information that can be stored on a disc so that a DVD-Audio disc can hold around 85 minutes of 96KHz, 24-bit, two-speaker sound - similar to CD but in much higher resolution and quality.
Alternatively, the disc can be recorded in 96KHz 16-bit sound in six-speaker configuration and provide 160 minutes of music - double that of CD. And if you want to go all out, you can store you can store up to 516 minutes of CD quality sound. The DVD specification also contains a bonus content feature that can add lyrics, sheet music, biographical and historical information, pictures and music videos to the disc, much like the additional content found on DVD-Video movies.
DVD-Audio discs cannot be played on a conventional CD player. You need a DVD-Audio capable player to play them, particularly the tracks recorded as high definition, and to access any additional extras. Some discs could be compatible with DVD-Video, depending on the sound recording format.
The DVD-Audio format does not use so-called 'lossy' audio compression on any of its principal audio content to maintain its resolution potential. Rather, the format features a special form of lossless compression called Meridian Lossless Packing (MLP). The main difference between lossy compression and MLP is that the lossless compression does not discard audio information and all the audio content can be completely reconstructed from an MLP file.
DVD-Audio uses MLP to resolve issues by reducing bandwidth and the size of the audio files so content can fit on a disc or actually be replayed by a DVD-Audio player. It will do so without loss of fidelity. No such claims are made for content manipulated with packed PCM (PPCM) compression. DVD-Audio discs can be enjoyed in two-channel home entertainment systems, but full home cinema set-ups will be needed to take full advantage of any six-channel tracks or encoding.
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