How to add alpha channel video as overlay?

Question

I am doing a video editing app. In this I need to add video overlay on another video. I am able to add video overlay by decreasing opacity. but when I am trying to add alpha channel videos(for transparency) its showing black background instead of transparent . I need transparent video for showing rain , thunder effect. Can anyone suggest how to add transparent videos. Thanks in advance.

Answer 1

Yes, this can be done but not with the built-in tools provided with iOS. See iPhone Smooth Transition from One Video To Another