Non-linear sync issue: a real p.i.t.a.

[Instant Martian]

Hi guys,
I have a new question for you.
I have several UK DVDs (PAL) to which I want to add an Italian audio track taken from AVI files (25 fps).
The problem is a non-linear out of sync.
I have read other threads here around and seems that it has to be fixed on a per-segment basis with VirtualDub, but this would be a huge amount of work since the sync issue occurs every few minutes.
I tried to feed the audio to Audacity and change the tempo to match exactly the video running time, but they are still not in sync.
Is there a way to do it in a simpler way?
Maybe a piece of software that can stretch/shrink the audio (the whole track) on a certain number of selected "key points"?
Does something of this sort exist?

[guns1inger]

The question is why they are out of sync, given they are both 25 fps movies (unless the DVD was released as an NTSC disc - it happens). This would imply that the two films are different edits of the movie, so simply stretching it here and there may not be enough.

The first thing I would do is load both movies into an NLE onto different tracks and try to determine why the films are different, then start working on the audio.

[Instant Martian]

Thanks for replying!
Yep, that is the question, but I don't have any idea of the reason.
The DVD is PAL interlaced 25 fps, the AVI is 25 fps too.
The only thing I did was to cut the opening credits on the avi since they are different from the DVD ones.
But the "core" part should be the same.
Anyway, I'll try to do what you suggest and see if I can understand where the problem is.

[Instant Martian]

Is there a way to visualize both videos (split-screen like) on the same monitor in Premiere Pro CS4?

[poisondeathray]

Is there a way to visualize both videos (split-screen like) on the same monitor in Premiere Pro CS4?

in PP, you could put video 1 on track 1, video 2 on track 2

track 2 (the upper track) , just move the x-position (in the effects control panel, motion properties) , e.g. slide it to the right. So now you have video 1's left half , and video 2's left half side by side

if you wanted the whole frame side by side, or on top of each other, just make a sequence that is 2x the size in the dimension you want to go (top or side by side) , and place them that way (i.e. stacked horizontally or vertically)

[Instant Martian]

Hi pdr, here we are again
I tried what you suggested for the split-screen but that was not exactly what I needed.
Anyway I achieved it using the "Four Point Garbage Matte".
Well, the two videos appear to be the same lenght, they are in sync at the beginning but there are several points in which something happens to the avi (like some frames are lost) and this cause the sync issue.
Is it possible to fix this? How?

[poisondeathray]

Very difficult to fix

Adjusting audio is harder than video (with video you could just add dupe frames, or delete frames until they match)

So if you want to keep DVD video , but add Italian audio that's seems to be a different cut, it's going to be very difficult

[Instant Martian]

I don't think they are different cuts, it looks more like the avi "loses" a couple of frames here and there (I don't know why), hence the sync issue.
Well, so it is hopelessly unfixable.
Shoot!

[poisondeathray]

I don't think they are different cuts, it looks more like the avi "loses" a couple of frames here and there (I don't know why), hence the sync issue.
Well, so it is hopelessly unfixable.
Shoot!

But the AVI audio is in sync with the AVI video ?

If the AVI video has a few frame drops compared to the DVD video , they can't be the same cut (if they are identical lengths, identical fps =25, this means they should have identical framecount)

[Instant Martian]

I didn't see the whole avi , just jumped here and there (beginning, middle, end), audio and video appear to be in sync.
The two video tracks don't have the same framecount because there are differences in the opening and ending credits but the "core" segments look the same cut, except for those "bad frames" in the avi.

[Instant Martian]

Well, I managed to resync audio and video.
I had to split the audio in 25 parts or so, made a lot of tweakings, integrated some missing seconds here and there with the english track,
adjusted the volume. There is only one point which I was not able to sync perfectly, there was no way to do it.
All of this for a 48 minutes video.
I have about another 80 episodes.
I am seriously pondering the thing.