On iOS 14, when we have AVCaptureSession setup wit AVCaptureVideoDataOutput, AVCaptureAudioDataOutput and also RemoteIO unit configured, AVCaptureSession sometimes takes upto 3-4 seconds to start especially when also changing AVAudioSession category from playback to playAndRecord. Is this because iOS14 is overall slow and buggy in the initial release or something specific to AVFoundation?

I have iPhone 11 Pro running iOS 14 beta 2. In one of my projects (and only that project perhaps), the view controller doesn't autorotate when connected to XCode (11 or 12) debugger. When not connected to debugger, there is no issue in autorotation. This happens for only one particular project and it's not clear what could be blocking autorotation. None of the autorotation methods are called. I wonder what could be blocking autorotation. And if I connect any iOS 13 device, autorotation works with the debugger. Is this a known issue with iOS 14/XCode?

Is there a way to get stereo audio on iPhone XS using RemoteIO unit, or any of the CoreAudio APIs? Need to record audio in stereo format.

I have CVPixelBuffer's in kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange, which is 10 bit HDR. I need to convert these to RGB and display in MTKView. I need to know the correct pixel format to use, the BT2020 conversion matrix, and displaying the 10 bit RGB pixel buffer in MTKView.

When using AVCaptureVideoDataOutput/AVCaptureAudioDataOutput & AVAsset writer to record video with cinematic extended video stabilization, the audio lags video upto 1-1.5 seconds and as a result in the video recording, video playback is frozen in the last 1-1.5 seconds. This does not happen when using AVCaptureMovieFileOutput. I want to know if this can be fixed or there is a workaround to synchronize audio/video frames? How does AVCaptureMovieFileOutput handle it?

iOS 12 seems to have lot of bugs in AVFoundation code it seems. The latest one seems to be one with AVPlayer:Cannot remove an observer <NSKeyValueObservance 0x280625ce0> for the key path "currentItem.status" from <AVPlayerInternal 0x107626840>, most likely because the value for the key "currentItem" has changed without an appropriate KVO notification being sent. Check the KVO-compliance of the AVPlayerInternal class.'Has anyone come across this?

I am using a RemoteIO unit along with AVCaptureSession to playback samples received from builtin or external microphone. The problem is AVCaptureSession freezes for few seconds in the startup if RemoteIO is simultaneously initialised. I want to know if there is a better and faster way to loopback samples received through AVCaptureAudioDataOutput to headphones? There is one sample code by Apple called AVCaptureToAudioUnit that uses AUGraph but it's pretty old and does not build anymore.

Dear Apple Engineers, This has happened twice with iPhone 11 Pro running iOS 14 beta 4. I have now filed bug FB8334182 and recorded vides and photos that have been attached. Because once the device enters this state, nothing works. Sysdiagnose fails to capture, iPhone can not be synced to Mac anymore, all apps either crash or freeze. Deleting files from system have no effect. And honestly, it is not clear why iPhone storage is increasing. The app I was debugging started showing increase in disk space in GBs when nothing was saved by the app anywhere. Now the iPhone is stuck in boot loop with Apple logo and the only option is to do a hard reset by installing a fresh copy of iPhone. There is no option to report in Feedback assistant that issue is with iOS. Had to report issue with UIKit instead!

Is it possible to get certified financial reports from Apple detailing sale of apps in different countries across the world along with VAT deductions? Online reports may not work in some countries for audit purposes, particularly when you have income from various countries.

Does AVFoundation exports only have fixed frame rate output in presets other than passthrough? In other words, do AVAssetExportSession & AVAssetWriter/Reader output/input ever output variable frame rate video? If input video was 29.43 fps, I see output video is always 30 fps when I render using the above two interfaces. Looks like AVF applies a default video composition while rendering.

The WWDC video gives compressionSettings for HDR10 and HLG but doesn't mention any setting for Dolby Vision. Is it not supported or I am missing something?

WWDC 2020 video 10010 says we need to specify MDCV and CLLI for encoding HDR10 video, but the question is how to determine the values for these fields from the camera?

I see some apps have started supporting Dolby vision 10 bit HDR recording but I see no AVFoundation API to enable it. AVFoundation engineers, please do let me know if I am missing any specific API to record video in 10 bit.

I want to know how AVFoundation handles variable frame rate compositions. I create an AVMutableComposition from a bunch of videos (most have variable frame rate as iPhone camera never shoots videos at constant frame rate), then assign an AVVideoComposition with a custom defined frameDuration. Then if I playback this composition or render it using AVAssetExportSession/AVAssetWriter, will the output always be a constant frame rate video and will AVPlayer play it as constant frame rate (perhaps by dropping frames)? Also how do I specify frame rates such as 29.97 or 23.98 for rendering and playback?

iPhone 12 pro and iPhone 12 pro max support HDR recording in 10 bit color space. But we are waiting for any documentation , dos/don'ts from AVFoundation Engineers and make apps ready for recording 10 bit video on iPhone 12 pro using AVCaptureVideoDataOutput and displaying the sample buffers using MTKView.