1) Click File>Add Video Files with Quicktime to add the source file, then convert again.
2) Try to play the source file on Leawo, if the problem exists when you previewing your files, please right click the added file to send us bug report.
3) If you can provide us a small source video file, it will be much more helpful.
The post The output audio goes out of sync with video, what can I do? appeared first on Leawo Support Center.