audio delay discrepancy

[mob]

Hi everyone.

When ripping a DVD with DVDDecrypter in IFO mode I can have it demux the audio tracks. This is giving me the AC3 files with "delay -66ms" in the filename.

But if I pass the VOB through DGIndex and use it to demux, it gives me the same AC3 files with "delay 0ms" in the filename.

Surely both can't be correct. So my question is, which one is?

Any help is appreciated. Thanks in advance.

[Guest]

You have an open GOP. DGIndex follows the MPEG2 spec and assigns the PTS to the first access unit in decode order, i.e., the I frame. But that frame is not the first in display order. As DGIndex also retains the orphaned frames by replacing them with copies of the I frame, it is correct to use 0ms when demuxing with DGIndex.

If DVDDecrypter discards the orphaned frames, it could also be correct if it is used for demuxing.

[mob]

Thanks neuron2.

I checked the hash values of both AC3's (the one demuxed by DVDDecrypter and the one demuxed by DGIndex) and they are exactly the same file.

So I am assuming that DVDDecrypter is wrong and just go with what DGIndex is telling me based on what you have said above.

Thanks again for your help.