Swift 3 : issue with AVVideoCompositionCoreAnimationTool to add watermark on video

Question

The following code was working perfectly to add a logo and a text to a video with AVVideoCompositionCoreAnimationTool. Then Swift 3 came! Now sometimes the video shows with

Answer 1

Seeing as the code works on iOS 9, this is probably a bug in iOS 10.0 where AVAssetExportSessions don't work properly when they have videoComposition set.

Some have reported that things look better in the iOS 10.1 beta and others have worked around the problem.