Problem synching audio

[marsman]

I'm processing some files that I transferred from video tape via ElGato video capture device. This one is a large mp4 file (mp4 is the default output from the ElGato) which, as usual using this device, has a problem synching the audio and video. (Note that subsequent to capturing this video, I have found that I can get an intermediate video file made by ElGato, a .ts file, that does not have the synch problem. The catch is that I have to find that file before ElGato saves the mp4 because the .ts file is autodeleted once the mp4 is saved. However, for this case, I have only the mp4.) I'm having a problem synching the audio and video for one particular segment of my sequence.

The method I use to try to synch the video and audio is to unlink the audio and video clips; then create gaps before and after the clips so there is room to move them around without overlapping other clips in the sequence; drag the audio or video clip until I feel the clips are properly synched; finally group the clips to keep them synched up.

This method has worked fine for me several times. In fact, after I  started having the problem described below, I tried the same method on a clip farther on in the sequence, and it worked fine.

Moving on to the problem. I proceed as described above, but when I drag the audio and drop it, the entire video clip ends up being moved all the way to the end of the audio clip. Ctrl-Z puts everything back the way it was. Moving the video has the same effect, although in this case the audio may end up at the end of the video. I also noticed during this process that the audio clip has a strange little split part way through. When I select the audio clip, it shows highlighted, but there is a short gap part way through that is not highlighted. The waveform in that gap looks like it drops to zero volume, but when I play it, I hear sound continuously. The rest of the audio clip beyond the gap is highlighted. If I hover over any of the three pieces, the properties that are shown (such as duration of the audio) are the same for all three of these pieces.

A really frustrating part of this is that I had the audio and video synched for this clip at one point, but somehow, even though I had the audio and video clips grouped, when I changed something earlier in the sequence, it knocked the audio and video out of synch in this part.

You can see a video that demonstrates some of this here:

https://www.dropbox.com/s/m3fcdohysfdqd4l/VID00002.MP4?dl=0

 

[borate]

Unable to replicate the video jump.  If all is UNlinked audio changes will not affect locked video tracks.  Right-click to the left of those tracks and LOCK TRACK.                           The 'gap' issue doesn't ring a bell.

Please use the latest VP version.  For licensed users upgrades are free for up to six months from purchase date.  After that, VP will continue to fully function but a fee will be required in order to register the newest.  Retain your old install file and registration info.

[Nationalsolo]

Hi

Perhaps the audio is corrupted as you report some odd breaks etc.

Try this..

• Place your copied video on the timeline
• Click the + that follows  Sequence 1 X. This creates a sequence and clears the timeline.
• Open the sequence bin and right click Sequence 1.
• Select Save Sequence Audio as a New File This should ensure you have a complete audio copy without any odd breaks etc. A copy is saved to the default folder on the PC that you set up under Options/Disc
• Close VP, Reopen VP and load your copied video
• Unlink the audio and delete Audio track 1. This will leave just the video without sound.
• Load your copied sequence audio to VP and drop it on Audio Track 1.
• Line it up at the start.
• Make a clean starting edge by Splitting all tracks and removing the bits( if any.)
• Close the gaps (if any)
• You are back to square one but with a "clean" audio track which start in synch.
• Check the end of the timeline
• Is the sound track too short? If so alter the speed of the audio gradually until the end matches the video

Does this get the synch back?

Nat

[marsman]

Nationalsolo,

Thanks for the suggestion. I was able get the audio synched using some of your suggestions. I shortcutted your method a little: audio and video were already unlinked, so I selected the audio clip and saved as new file. Then deleted the clip from the audio track, loaded the saved (.wav) file. Then I was able to move audio and video around to synch. When I was satisfied, I grouped the audio and video clips to keep them together.

Thanks again.