AVCompositionDebugVieweriOS

This sample application has an AVCompositionDebugView which presents a visual description of the underlying AVComposition, AVVideoComposition and AVAudioMix objects which form the composition made using two clips, adding a cross fade transition in between and audio ramps to the two audio tracks. The visualization provided by the sample can be used as a debugging tool to discover issues with an incorrect composition/video composition. For example: a break in video composition would render black frames to screen, which can easily be detected using the visualization in the sample.

The main files are as follows:

APLViewController.m/.h:

The view controller setups playback of AVMutableComposition and also initializes an APLCompositionDebugView which then represents the underlying composition, video composition and audio mix. It also handles play/pause and scrubbing utilities.

APLSimpleEditor.m/.h:

Simple editor setups an AVMutableComposition using supplied clips and time ranges. It also setups AVVideoComposition to add a crossfade transition.

AVCompositionDebugView.m/.h:

 A subclass of UIView that represents the composition, video composition and audio mix objects in a diagram. It also contains a time marker layer which is synchronized to the current player item using AVSynchronizedLayer, to track the currentTime of a player.

main.m:

Standard main file.

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