Audio authoring problem

[alewisa]

Not sure if this belongs here or in the Authoring topic, but lets start at the bottom!

Ok, authored a movie using DVD Lab. On the pre-burn test, I noticed the audio was way out of sync.

Went back to the app, and noticed that the audio file was 6 seconds shorted than the video.

Method.

Extract soundtrack from .avi source using VirtualDub, saved as .wav
Convert .avi to elementary video stream using MPEGEncoder
Converted .wav to elementary audio using MPEGEncoder
Added to DVDLab, authored to .VOB. PowerDVD used to test vobs.

Once I noticed the difference in track lenght, I used Goldwave to extract audio. Same result

Added the raw .wav to DVDLab - just to test. Same result
Used TMPGenc DVD Author - same result (audio is 6 seconds shorter)

What I havent done (after reading through the forums)

Looked at the reported audio track length in VDUB/Goldwave

Looked at the audio length by using MPEGEncoder to convert both streams from the source .avi (see if there are discrepancies)

Question.
In an .avi file, is it possible to have a sound stream actually start, say, 6 seconds into the file, rather than at the same time/point as the video data? In which case I would just add say 6 seconds delay in the authoring, or 6 seconds of "zero sound" at the start of the sound file?

IF the sound starts and ends at the same time as the video in the .avi file, why, on ripping, would it be 6 seconds shorter? Original audio is 48KHz, extracted file is 48KHz.

If none of the above, what should I look for? What are the "cures" - Timewarp in Goldwave? Audio delay in authoring?

Any "heads-up" type clues/answers appreciated. I'll post more info specific to the problem when I get home and get 30mins with it. Apologies if I haven't searched for enough answers in forums (I have searched on some, and read the replies) but as I type this some thigns occur to me, so using the forum as a sounding board and trying to think the solution out to myself as well!

And if you are clued up on AC3 - well, I'll be asking a question on that, later, too

TVIAM!

[Patwig]

At this moment I am thinking that an AVI file has a correct-length audio file, even if there is silence at the beginning. I am assuming this because of my experience with Pinnacle Liquid Edition. Create AVI from timeline, including blank spaces. (I humbly retreat from this position if challenged).

What I am using
CinemaCraft Basic encoder for mpeg 2 file. I do not encode sound file.

ffmpeggui for AC3 file encoding. I encode directly from the original AVI file (sound embedded in file).

Drag both encoded files into DVD Lab. There is a several second difference in sound and video files that displays in DVD Lab -- however, there is a perfect sync in the final result.

Am well happy with these apps. tho I have heard that ffmpeggui AC3 may not be compatible with ALL dvd players. As you may know TMPGEnc also sells an AC3 encoder that, I understand, serves as a stand-alone encoder.
It may have perfect AC3 standard compliance?

Patwig

[indolikaa]

Have you tried an -RW or +RW burn anyway, too see if the final product still has the lag in question?

[hiptune]

Converted .wav to elementary audio using MPEGEncoder

Once the wav has been created fron the avi, it is already an elementary stream, I believe there is no need to process audio any further.

Simply drag that wav into authoring program as is.


This may not help your sync issue, but it is one less step you need to mess with.

Jeff