Do DVDs actually REQUIRE uncompressed audio?!?

[miamicanes]

What's the relationship between 48kHz LPCM and mp3 insofar as DVD video tracks go? Is the LPCM audio literally multiplexed into the VOB file more or less unchanged (and full size) as uncompressed PCM audio, or does/can it get converted to some more space-efficient format (like MP3) along the way?

It just seems totally perverse to tie up the computer for hours at a time so TMPGenc can efficiently encode a video clip using something like 2400kbit/second VBR, then turn around and squander 1.5mbit/second on raw uncompressed 16-bit audio (16 * 48000 * 2 = 1536kbit/sec)... Given a bit budget of 4,000 kbit/second, I think it's a no-brainer that 3600kbit video + 256kbit MP3 would give far more "bang for the bit" and produce more appealing results overall than 2400kbit video + 1536kbit uncompressed PCM audio.

Assuming the conversion of LPCM to MP3 (or some other more efficient scheme) isn't automatic, is it at least ALLOWED?

[wulf109]

Vertually every DVD sold uses ac3 audio which is a compressed format. Very few DVD's use PCM audio,usaullly concerts.
Tmpeg supports mp2(mpeg) audio which is compressed at the ratio as ac3.
I don't believe Tmpeg even supports PCM except to convert it to mp2.

[Thorn]

If you're in the USA, most dvd players won't play an mpeg audio/mp3 audio track on a DVD. In Europe that will work fine and is probably the better choice.

In the USA, your choices are pretty much AC3 (dolby) and PCM. Yes, the PCM takes a lot of space, but it's considered the nonprofessional choice because a lot of the cheaper authoring programs will only allow you to use PCM audio. There is one free AC3 encoder, but you still need the get around the authoring program.

By the way, yes it is very difficult to fit a lot of video on a disc using PCM. Typically you'd want to have less on each disc or go "pro" and use AC3.

[Jester700]

It's not the standard, but MP2 is a popular audio format in use in DVDs.

[wulf109]

I live in the U.S. and own 5 DVD players and everyone of them supports mpeg audio on DVD. Mpeg audio for DVD is mp2 not mp3.
It's true that mp2(mpeg audio) is not technically part of the DVD spec. but any DVD player that supports playback of VCD/SVCD will play DVD with mpeg audio.