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4. What are the requirements for DVD compliant audio?
The DVD specifications allow for LPCM (uncompressed), AC-3 (Dolby Digital), MPEG Audio, and DTS (Digital Theater Systems). The official requirement is that all NTSC discs must have at least 1 AC-3 or LPCM audio stream, while all PAL discs must have at least 1 AC-3, LPCM, or MPEG Audio stream. Because of this (and because DTS support is optional in DVD players) it's generally not a good idea to have only DTS audio on a DVD, however if you have a player and stereo that support DTS it may not be a problem. MPEG Audio is also questionable on some players. You may run across an NTSC player that doesn't support it (though this is rare) and you may not be able to output it using a digital connection.
LPCM
LPCM audio may be sampled at 16, 20, or 24 bits, with a frequency of either 48kHz or 96kHz, and up to 8 channels, but using anything other than 2 channel/16 bit/48kHz LPCM doesn't work correctly (or at all) on some players.
AC-3
AC-3 audio may be sampled at up to 24 bits, with a frequency of 48kHz, and anywhere from 1 to 7.1 channels. AC-3 is generally categorized by bitrate, and the DVD specifications allow for bitrates between 64kbps and 448kbps. 2 channel AC-3 audio is generally encoded at 192kbps, while 5.1 channel is normally at either 384kbps or 448kbps.
MPEG Audio
According to the DVD specifications MPEG Audio is only supported on PAL players, but in reality most NTSC players can play it, especially if they also play VCD or SVCD. MPEG audio may be sampled at 16, 20, or 24 bits, at 48kHz, with anywhere from 1 to 7.1 channels. Like AC-3, MPEG audio may be encoded at different bitrates, although the range is 32kbps to 912 kbps. Like LPCM, playback of anything other than 2 channel/16 bit/48kHz MPEG audio can vary from 1 player to another.
This message has been edited since posting. Last time this message was edited on 28. November 2005 @ 03:27
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