This free tool can help you create a split screen video by putting two video files side by side, joining two video clips together, merging them and playing them simultaneously. With the "Layout" option, you can control how your video files are stacked. If you select the "Left and Right" value for the "Layout" option, your two video files will be placed side by side and stacked horizontally, one on the left and the other on the right. If you select the "Top and Bottom" value for the "Layout" option, your two video files will be stacked vertically, one at the top and the other at the bottom. The output format is MP4 video.
With this option, you can select the duration of the generated video. The option values include "Video 1 (Video 2 Loop)", "Video 2 (Video 1 Loop)", "Video 1 (Video 2 No Loop)" and "Video 2 (Video 1 No Loop)". By default, the duration value is the longest of the two video files, and the other, shorter video will loop.
The default audio for the generated video is a mix of the two original files, but you can specify that only one of the two video files be used for audio. The option values include "Default", "Video 1" and "Video 2".