Audio Sync Slides Out Then Back In

[Visitor99]

Hello...

I have a video recording of a live event with unuseable audio. I was able to get clean audio from the hall sound board and now I would like to sync the two. I'm working in Adobe Premerie Elements 3.0.

I located two sync points, one at the beginning of the event and one at the end. I sync'd the beginning by sliding the audio under the video until it matched, then sync'd the end by adjusting the speed of the audio. Now both the beginning and ending of the recording are in perfect sync.

However, as the recording plays back, the audio starts sliding out of sync until it gets to the mid point of the recording, then starts sliding back in sync until it is fully sync'd again at the end of the recording.

The video is in MPEG-2 format, the audio is a WAV file.

I'm really stumped on this one, thanks in advance to anyone that can help me out.

[Visitor99]

Hello...

After hours of searching I found the problem, and it wasn't with the audio as expected.

It turns out that every few minutes, one or two frames of video were missing. This meant, essentially, that the video was not running at a constant speed as expected. This in turn caused the audio to drift in and out of sync.

The problem was hard to spot (and fix) because only a very few frames were dropped, and not in a predictable way. I corrected the problem by resyncing the audio with the video after every frame drop.

[peterhun]

I got a problem where the audio is sync ok at start but by the end the audio has finished while the video keeps on for 6 more minutes.
Can you describe what prog you used and how could I drop some frames to let the video catch up to the audio.

[guns1inger]

I got a problem where the audio is sync ok at start but by the end the audio has finished while the video keeps on for 6 more minutes.
Can you describe what prog you used and how could I drop some frames to let the video catch up to the audio.

It sounds like you have changed the framerate, probably during a botched PAL/NTSC NTSC/PAL conversion. Dropping 6 minutes worth of frames will give you a very jerky video. Better to actually fix the problem, than create a new one.

Start by describing the source, what you have done to it, and post a g-spot screenshot if you can

[Visitor99]

I corrected my sync problem by time stretching the audio using Adobe Premier Elements 3. The time stretch function has a "keep-pitch" setting that allows you to do this without changing the pitch of the audio.