TMPGEnc's "Audio gap correct".

[proctor]

Hi, I've been using "Sefys classical newbie start DVD Ripping guide" for a long time now .. and I noticed that some of the times .. the audio isn't synced with the video and I need to use the "Audio gap correct" in the "Source rage" menu to fix it (either move it -xxx or +xxx). Why does this happen at all? I mean.. if I rip the DVD ... shouldn't it rip the right audio and video from the beginning to the end in the first place?

Thanks in advance if you can clarify things for me.

[adam]

I believe that guide uses dvd2avi to process the audio. Dvd2avi has bugs in this area which can cause desync depending on the particular DVD. These bugs will also be more prevalent if you use any version other than 1.76 or possibly the very latest release.

The audio on a DVD is not actually "synced" up with the video exactly. The Ac3 tracks are usually either slightly longer or shorter than the video track, and there is a + or - delay in the stream to compensate. Don't ask me why they do this but I'm sure there is a reason. So, from my experience, dvd2avi does not always properly handle this delay, especially if you use dvd2avi to only select a portion of the video to process.

My suggestion is to either use your ripping program to demux the audio straight to AC3, or set dvd2avi to demux instead of decode. From there encode the AC3 file directly to mp2 using BeSweet. From there you can multiplex this directly with your encoded video stream. BTW when using BeSweet, there is a spot where you put in the amount of AC3 delay. Usually the program that creates the AC3 file (ripper or dvd2avi) will list the number of ms of delay in the filename of the AC3 file.

[proctor]

You said that I should have my ripping s/w demux straight to AC3 .. do you think that DVDDecrypter can do this?

[adam]

Yes DVDDecryptor can do this. If in IFO mode click on the stream processing tab, select the tracks you want, and set it to demux. If in File mode, highlight the set of vobs you want, right click, and then again select your desired tracks and set it to demux.

[proctor]

I'll give it a go .. I'll get back to you if I have any more problems with this.
Thanks for your help.