AVPlayer playback fails while AVAssetExportSession is active as of iOS 10

Question

AVPlayer will randomly just play audio, not showing the video track...

Playing video correctly with AVPlayer while having an active compres

Answer 1

I found a solution to my problem. Like Sami said, the issue appears to be in AVVideoCompositionCoreAnimationTool which I was using to watermark my video. I shifted to using a CIFilter, which actually had cleaner code anyway.

I removed everything with CoreAnimationTool and used this (mixComposition is my AVMutableComposition):

let watermarkFilter = CIFilter(name: "CISourceOverCompositing")!
let watermarkImage = CIImage(image: #imageLiteral(resourceName: "watermark"))!
let videoComposition = AVVideoComposition(asset: mixComposition) { (filteringRequest) in
    let source = filteringRequest.sourceImage.clampingToExtent()
    watermarkFilter.setValue(source, forKey: "inputBackgroundImage")
    let transform = CGAffineTransform(translationX: filteringRequest.sourceImage.extent.width - watermarkImage.extent.width - 2, y: 0)
    watermarkFilter.setValue(watermarkImage.applying(transform), forKey: "inputImage")
    filteringRequest.finish(with: watermarkFilter.outputImage!, context: nil)
}

and then in the AVAssetExportSession added this:

exporter!.videoComposition = videoComposition

Hope that helps somebody!

Answer 2

Just heard from Apple DTS. They also agree this points to an Apple iOS bug and asked me to log it.

I cut out usage of AVAssetExportSession altogether and it solved the issue. So calling AVAssetExportSession in combination with other AV methods is what causes the iOS instability.

In my case I was usingAVAssetExportSession for post capture compression. So instead I used AVAssetWriter to sample each frame in real-time to the format I needed...

This should be fixed soon by Apple, hopefully.