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Audio Sync

Posted: Wed Nov 28, 2018 5:24 pm
by Bob L
So, in the age of talkies what good is a video editor that can't keep the audio in sync? I was falling for the variable bit rate excuse until I used the Screen Recorder option and found that even on recordings made by Videomeld it can't keep sync. Sure if you use the wmv format it's not as bad but still. I've been using Goldwave for audio for maybe two decades and found it to be a quality product and since I can't figure out how to install Microsoft Movie Maker on my new computer I was glad to see Goldwave had a similar product. The trial was difficult and limited but because it was a Goldwave product I bought the full license. Wish I had that $50 back.
Sure this video business is complex and confusing but that's why you can sell a product that should deal with it. So to the brain trust at Videomeld maybe this is a clue. When Movie Maker loads a video it spends a long time working on the audio. And then when you get to the editing the video is chopped up into a lot of little segments each only a few second long. Think about it. Does that sound like a lot of work. Please get to work and maybe you can save Goldwave's reputation.

Re: Audio Sync

Posted: Sun Dec 09, 2018 3:01 pm
by Bob L
Problem solved! Chris at Goldwave reached out and gave some very useful guidance. The key is to use the "Decode Audio To Wave File..." feature.
Step by step it works like this:
1. Load the video (with audio) file you would like to edit by clicking on the "Track" drop down then "Add Video..." Find your file and load it in.
2. Before you do anything else click the "Options" drop down and select "Section Settings..." In the resulting pop up the second line has a gray box containing "Decode Audio To Wave File..." Click on it.
3. This gives you a "Save As" pop up. From what I can tell you will never use this file but I guess VideoMeld needs it. You may delete it after you are through editing. Click "Save" and VideoMeld does the conversion and then automatically replaces the audio track with the converted data.
4. Click "OK." Note that some times this gives and error message: "'To' time cannot be beyond the length of the file." I've been able to get around this by clicking the "All" button to the right of the "to " time. That time changes and when I click "OK" a second time it completes successfully.
And there you are. As Chris explains it the .wav data has a constant bit rate and stays synchronized with the video. Do your editing and it seems you may save the result in whatever format you choose. I've tried .mp4 and .wmv and the audio stayed in sync on both. I thought the video was slightly better in .wmv but it probably depends on your other settings.
So, I hope I got this right and that you find it helpful. Thank you to Chris for the guidance.

Re: Audio Sync

Posted: Sun Dec 09, 2018 8:52 pm
by Bob L
Oops, caution with this. As I'm doing more editing I'm running into trouble with the audio sync again. On a larger file, an hour and a half, that had that To Time problem it loses sync. The To Time discrepancy is 0.3108750 seconds and that seems the possible difference so maybe I'll try to insert something that long at the beginning of the audio track and see what happens.
Well, easier said than done. Maybe I'll try again some other time.

Re: Audio Sync

Posted: Wed Dec 19, 2018 11:06 pm
by Bob L
Well, sometimes it works. Sometimes not. We got passed some problems sometimes but there were others. The Videomeld people don't know why. Save your money. Wish I had mine back.

Re: Audio Sync

Posted: Wed Dec 26, 2018 4:47 pm
by GoldWave Inc.
Aside from the variable bitrate problem, it is also caused by differences in hardware timing. Audio devices have their own clock. That clock can vary from one device to another (and from the timestamp attached to the frames). You can use the "Speed" section setting to adjust for that difference.

Re: Audio Sync

Posted: Sat May 07, 2022 5:06 pm
by patrice
I know this post is old, but I'm having the same problem. What really bugs me is that after I record a video using VideoMeld; if I play the captured .mp4 file using a video player (VLC in this case) the audio is perfectly sync'd. If I play the captured file in VideoMeld the audio is out of sync, late by about 1/2 second, which is enough to be noticeable and annoying. What I want to do is make some editing, e.g. cut parts of the recordings, but when I meld the project to video file, the audio is off as when I play it in VideoMeld.

Is there a setting somewhere I am missing? Alternatively is there a way to automatically re-sync the audio? I tried the "Decode Audio to Wave" trick, but that did not help.

Re: Audio Sync

Posted: Wed May 11, 2022 10:11 am
by GoldWave Inc.
Can you try VideoMeld on a different computer to see if the same problem occurs? If it does, perhaps you can upload a sample video for testing so we can track down the cause of the latency.