If the video and audio are out of sync after exporting, you can follow the instructions below:
1.Make sure all of the media is in sync before loading it into Filmora scrn.
2.Reload the media into the program. Then zoom in on the timeline by dragging the slider and to double check whether all the elements on timeline have been aligned properly.
3.Adjust the output settings to be similar to the input media before exporting. To check the settings of your imported media, You go to the media library and find the input media file. Right click on it and choose Details. Refer to this information to adjust your output parameters, including resolution, frame rate, and bitrate.