Thanks for your reply. I have uploaded a sample project in Feedback Assistant: FB16546544 When doing the sample I found that the problem isn't the usage of kCGImageSourceDecodeToHDR, since kCGImageSourceDecodeToSDR results in the same problem. The usage of non-nil options for the CGImageSourceCreateImageAtIndex demonstrates the issue. You will see in the sample :-)

The problem with outputVolume is that you only get notified when the volume change. If the volume is 0 and you push vol.down, nothing will happen. Or if volume is 1, and you push vol.up, nothing will happen. Previously using AVSystemController_SystemVolumeDidChangeNotification and SystemVolumeDidChange in combination, fixed that. So we need a more robust solution that outputVolume