Audio tracks out of sync to video

PJ77

Hi all - I'm hoping someone can help... So I have recorded an instructional video using my iPhone (audio recorded separately). I have got several video clips along 1 video track in Videopad Video Editor and various audio clips along an audio track. I have positioned the audio to correctly sync with the video. When I export to a video file (tried numerous settings), the audio is not synced properly, and it gets progressively worse the further along the video I get.

I have tried putting audio clips on separate audio tracks, grouping audio and relevant video clips together etc, but cannot seem to get the output video to sync properly. Any advice would be much appreciated!

More info:
Videopad Video Editor v13.81
Mac OS Sonoma 14.5 running on a Mac mini Apple M1 chip, 16GB RAM

borate

Let's take a look at the project, which is the best way to track down issues. The process is easy, quick and can be done privately. Just follow these steps closely...

Back up --- With your project on the timeline, click on MENU at the top-left. Click FILE|BACK UP PROJECT FILES TO FOLDER. Choose a folder and SELECT FOLDER.
Upload --- Use a free server - Google Drive, MS OneDrive, etc.* - to upload the saved, numbered FOLDER. Do NOT upload the individual VPJ or export file.
Get link --- Get a public link. Right-click the file and click SHARE. When using Google Drive, if necessary change "restricted" to "anyone with the link can view"
Share --- Click COPY LINK | DONE. Paste that link here, or click the folder at the top-right of this forum to message it privately to me. It won't be shared.

* Before uploading, right-click the folder, click PROPERTIES. Look at the File Size to confirm that it's not too big for the free space on the server.

You can also test an earlier MAC version.

proj65

I have the same problem.

Video recordings of 30 minute Zoom meetings that are uploaded to VP have the audio lag behind the video. The rate of lag is not consistent. I have to edit the video and adjust the speed of the audio to be somewhere between 98 and 99.5% of the source. However, this isn't sufficient, as the percentage changes, so later in the meeting, it might require the playback speed to be 97% or 100%

It seems to be the processing of the video import.

Any ideas?

PJ77

Borate that helped me took my file and corrected the sync and bounced it - end result was correct, but I could not make it work on my system. When I do my next video I will try again, but Borate was on a Windows system and I’m using a Mac - don’t see why that should be an issue - it is a high powered Mac and should handle it :-(. Hope you get sorted.

proj65

Thanks for the info. This is a repeatable issue. It happens every time I upload a Zoom meeting video. I need a solution to this.

One idea I had was to split the source video into separate video and audio files, before loading into VP. This should reduce the work intensity for VP. I used Audacity to do this, creating an MP3 file.

When I imported the original AV file (MP4) and the audio file to compare, you can see that at the very start of the timeline,

- the AV is out of sync by 1 second after 14 seconds of the file. https://i.imgur.com/w85HWWy.png

At the end of the timeline, it is more interesting.

- The AV audio has differed in its offset, and by 37:46, it was down to 2 seconds ahead.

- The AV was not imported correctly into VP, because it is a total length of 37:46, instead of the actual source video length of 38:14

- The audio of the AV file is truncated to match the length of the video in the project.

- The audio file is correctly 38:14 in length, matching the length of the source file.

https://i.imgur.com/nmv1a46.png

So it seems the problem lies in the import of the video file, not the editor itself.

borate

What version of Videopad is being used? Look at the left-bottom corner of the window.

If you take a few minutes to share the project, someone can track this down. Follow the instructions in the above post to the letter and we'll take a look.

Please load the original Zoom mp4, not the split.

proj65

2024-08-21 23-55-08 is a link to a public folder with the project file and the Zoom MP4.

It wasn't clear to me where the folder in the top right is that you're referring to, so I was unable to check the available space on the server.

Thanks

borate

Occasionally this has been seen with mp4 files. Handbrake.fr will fix it for free.

Please leave your file on the server for a few days so others can have a look at it.

proj65

Thanks for your help. This issue happens with every Zoom video I import into VP.

Can you explain how an MP4 created by Handbrake is different to an MP4 created by Zoom?

borate

Handbrake re-encodes the file, which eliminates the fault.

A bug has been filed so it's likely that the slippage will be fixed in a future Videopad version.