AC3 Dolby Digital sound

[TXDVDfan]

I have been trying to backup a copy of my MIB DVD to VCD to see how good the quality would be. I used SmartRipper and DVD2AVI and TMPGEnc.

I have read in the various guides that you can pull the AC3 audio stream off the vob files with DVD2AVI in order to keep the true 5.1 . This seemed to work, but the file was much smaller(137 mg) vs the downmixed dolby 2.0 wav (1 gig) I created. Is the AC3 format normally that much smaller, or is something not right?

Also, TMPGEnc wont let me choose an AC3 file for the audio source. It wants a wav file.

Any suggestions?

[Ostaf]

Looks about right. raw wav files are significantly larger then AC3. It's like MP3 vs raw. And I've never been successful at getting a 5.1 channel audio onto an SVCD, but I haven't really tried all that hard.

[TXDVDfan]

Thanks Ostaf. Do you get better quality with SVCD vs VCD? Doesn't it require a lot more HD space for the mpeg file?

[Ostaf]

it depends on the bit rate. If you encode an SVCD as a two-pass VBR at 1150 (VCD bit rate) then it will come out as the same size as a VCD but usually have a significantly higher quality.
As near as I know, SVCD does support dolby 5.1 audio, where as VCD doesn't. I do have reference to a program called BBMpeg that will supposedly mux Mpeg and AC3 audio together, although I've never used it so I can't gaurantee any results.