Open your newly created video file in your player of choice and make sure it’s all synced up.MP4 files (MPEG-4 Part 14) are multimedia files. Click the OK button and then exit out of Avidemux.
Leave the video type as mkv and then click the Save button.
Once you’ve downloaded and installed Avidemux, open it.
Note: the screenshots used below are from a Mac, but the steps and screens are nearly identical if you’re using Windows or Linux and you should have no trouble at all following along. It’s cross-platform which means it’s available for Windows, macOS and Linux.
To permanently fix out of sync audio and video, you’ll need to download an open source (free) video editor, Avidemux. Permanently Fix Out of Sync Audio and Video Let the video play while you’re making the adjustments – but note that it’ll take a second or three for the change to take place each time you adjust the sync timing. In both instances, when you use the up and down arrows it will adjust your audio by 1/10th of a second per click. So in reverse, if the audio is behind the video you’ll want to use the “down arrow”. Use the “up arrow” if the audio is ahead of the video.Locate the section titled Audio/Video – within that window there’s a ‘timer’ with “up and down arrows” to adjust the timing of the audio.
This step by step guide will show you how to fix out of sync audio and video in a video file.