Exercise project on MPMoviePlayer, UIImagePicker, AVFoundation (AVMutableComposition, AVMutableVideoCompositionInstruction, AVVideoCompositionCoreAnimationTool, AVAssetExportSession), and QuartzCore (CALayers, CABasicAnimation, etc).
User can pick 2 to four movies to stitch together and have fade-in/out animations rendered at the start and end of the movie. Exported movie saved to the app's private storrage (not to photos to avoid clutter).