When most people think of DVD, what they have in mind is DVD-Video, the fastest-starting consumer-entertainment format in history. As you'd expect, the DVD format was defined from the start with an emphasis on video presentation.
Of course musicians know that the “other” DVD format is DVD-Audio (DVD-A), which uses the same physical medium as DVD-Video. DVD-A has different content definitions that emphasize audio fidelity and offers navigation features designed to appeal to the music listener. For music producers, it might seem natural that DVD-Audio would be the format of choice. Alas, the situation is not that simple.
DVD-Video has had a mature specification for several years and has an installed base of many millions, but the specification for DVD-Audio was only truly finalized in 2001. Today, “combi” players for both DVD-Video and DVD-Audio discs are available, but they represent a small fraction of players in the field, and sales of DVD-Audio titles have languished.
Dare To Compare
What's so great about DVD-Audio? The table “DVD-Video Versus DVD-Audio” compares the features of DVD-A and DVD-Video. Both can deliver uncompressed 24-bit PCM stereo at sampling rates well beyond those of CD, although DVD-Audio is capable of sampling rates as high as 192 kHz, while DVD-Video tops out at a “mere” 96 kHz.
When it comes to surround, though, DVD-Audio wins the fidelity contest hands down. In DVD-Video, all multichannel audio data is compressed, using either Dolby AC-3 or DTS. Depending on the format and data rate selected, audio fidelity will be affected to a greater or lesser degree. In DVD-Audio, on the other hand, up to six full-bandwidth channels can be rendered, without compression, at resolutions as high as 24 bits and sampling rates as high as 192 kHz (stereo).
Though DVD-Audio does not use data compression as such, it does make use of lossless bit-packing to deliver multiple channels at higher resolutions and sampling rates and to extend playing time. The bit-packing technique, Meridian Lossless Packing (MLP), guarantees bit-for-bit accuracy of audio data, eliminating any potential loss of fidelity.
In DVD-Video, still pictures are always tied to sound, so that it becomes impossible for the viewer to switch to a different still picture without also jumping the audio to a new location. In DVD-Audio, the listener can surf liner notes, artist pictures, or lyric sheets freely while audio continues uninterrupted.
DVD-Video also includes options for user interactivity, driven by small sequences of commands that are embedded in the navigational structure of the disc. Commands available include conditional logic, random-number generation, and full Boolean and hexadecimal arithmetic, so that user interaction can be fairly rich. In DVD-Audio, such options are severely limited. This is an excerpt from the following article: What About DVD-Audio.
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