Demux or Decode

[Sp33d]

I'm creating a project to use in the DVD to DVD-R process. When do I select Demux and when should I select decode for the Dolby Digital?
Demux gives me an .AC3 file and Decode gives me a .WAV. Is there any reason to use one over the other. More compatibility with authoring programs?

Thanks :)

[hakko504]

First, AC3 files are much smaller than WAV, thus saving space on the DVD-R. Second, WAV are downmixed to 2 channels so you loose 5.1 sound. Third, DVD2AVI's downmix isn't the best available so even if you want WAV files you should use Besweet (or azid) to convert from AC3 to WAV.

Conclusion: almost always use Demux.

[Leitz]

Originally posted by hakko504
...WAV are downmixed to 2 channels so you loose 5.1 sound.

Are you sure? I thought the WAV are only downmixed if you use "Dolby Surround Downmix" in the Audio->Dolby Digital menu (DVD2Avi 1.76) ?!

But I never tried it for myself. ;)

[hakko504]

Originally posted by Leitz


Are you sure? I thought the WAV are only downmixed if you use "Dolby Surround Downmix" in the Audio->Dolby Digital menu (DVD2Avi 1.76) ?!Yes, and no.
Yes, they are only downmixed if you check that box. No, I'm not sure if you get multiple WAV's if you don't check it, but I don't think so. If I recall correctly you only get the front channels in the WAV if you don't check downmix from 5.1 thus loosing ALL sound from center/surround/sub channels. I do know that Besweet/Azid can make 3 separate wav containing ALL sound from an AC3 (first containing front channels, second surround, and third center/sub) and if you are going for ogg sound this is a better choise.
In my case if I want 5.1 sound I use the demuxed DD5.1 file and otherwise I use besweet for downmixing.