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Sychronize video and audio


TequilaToo
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I captured an on-demand video with Debut and saved it as an avi file. The video played on my computer with audio and video perfectly in sync, but when playing back the captured recording, the video "stalls" for a couple of seconds at the beginning, but the audio starts immediately, so they are badly out of synch throughout the whole 1 hour video.

 

I have been playing with VideoPad to try and unlink the audio from the video (it won't unlink by right-clicking on the audio track, but if I right click on the file in the file list it gives me the option to unlink audio). However, I can't for the life of me figure out how to clip the first few seconds of the video track only, so that it will start at the same time as the audio starts.

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Hi

 

I have no idea why your video "stalls" for a couple of seconds at the start, but the problem you now seem to have is similar to a recent short film I made of a fireworks display where the distance of the camera from the event resulted in a 2.5 second delay between the visuals and the sound. Yours seems to be the reverse of this.

In practice this should be fairly easy to resynch. Assuming that the desynch lasts the whole length of your film and stays constant....

I gather from your description that when played in VP the video track just shows a "stalled" bit of film at the start.

So...Load the clip/film to the timeline. Right click the video track and select "Unlink from audio"

Grab the audio track and drag it to the right a little, just to separate the tracks.

Now look for a visible "peak" in the sound track at some point that corresponds with a visible effect in the video track.

You should be able to estimate the amount of desynch you have by referring to the timescale values in the small window below the right hand preview pane, for both positions.

Set the red line cursor on the visual effect and then drag the sound track peak to the cursor line.

Play the clip to check it looks OK

 

As regards the section of clip that now has no sound at the start; presumably the visuals are not playing at this point, being "stuck". There's little you can do about this apart from probably splitting this bit off, unless you can drop something onto soundtrack 2 there from elswhere in the soundtrack that is similar and blend it in.

 

Nat

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Thanks Nat - your post reassured me that I should be able to do what I wanted to do. I think the difficulty was with the length of the clip (almost an hour), which made it difficult to tweak the audio track just 2 seconds...once I figured out how to zoom in on the track, I was able to do it. I had also failed to "drag" the video clip into the timeline, and that's why it wasn't showing me the option to "unlink from audio". It isn't perfect, but it'll do...for this time. What I have to figure out now is how to prevent Debut from doing the same thing again.

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