Audio delay - how to correct it

[janger]

Hi everyone.

This is something my newbie brain doesn't understand. And searching the forum hasn't helped.

I have some recordings from a dvd recorder that need to be re-authored. When demuxing my vobs with DGIndex there is sometimes a fair bit of audio delay. If I go to re-author the elementary streams with apps like GUI for Dvdauthor, there doesn't seem to be an audio delay correction option. What is the proper way to handle this if I want to ensure everything stays in sync? Should I run the ac3 audio through Ac3 Delay Corrector or Delaycut before importing? Until now I've mainly used 'one-click solutions' for authoring. But I'd like to switch to an all-freeware setup, which requires a bit more work and understanding.

[Matthew]

I don't use a GUI for dvdauthor, but usually one uses mplex to mux and then dvdauthor after that. mplex supports specification of an audio delay.

Apart from that, you can correct the delay using AC3 delay corrector or delaycut. Bear in mind that AC3 frames are 32 milliseconds, so you will often be a touch out (up to +-16 milliseconds). e.g. a +100 ms delay will be reduced to +4 ms by removing the first 3 frames (3 x 32ms). But it's not like you'll notice such a small delay.