Hi Apple Team, We have integrated FairPlay Streaming Server SDK v3 into our MDRM platform since 2017, the system works stable and stayed untouched. As you know, both Widevine and Playready have requirements to upgrade the Server SDK regularly. We want to know if Apple imposes similar requirements for upgrading the FPS SDK, or if we may continue using the old one without any updates. Thanks for your support！

Is it possible to use the AVExternalStorageDevice to access external storage from a connected camera or usb drive (via USB C or Lightning connector) on an iPad/iPhone. I have tested the following code on an iPhone 14 (iOS 18.1.1) and an iPad Gen 10 (18.3.1), and both return false for: // returns false on iPhone 14, iPad gen 10 print(AVExternalStorageDeviceDiscoverySession.isSupported) The following code returns null, when I try to access the external storage discovery session. // returns null on iOS devices print(AVExternalStorageDeviceDiscoverySession.shared) The following returns false, without displaying a permission dialog: AVExternalStorageDevice.requestAccess(completionHandler: { (granted: Bool) in // returns false with no permission dialog print(granted); What type of iOS devices are supported by AVExternalStorageDeviceDiscoverySession? What situations has it been used for (e.g. connecting to Camera via the external storage protocol, accessing photos from a SD card with an adapter, accessing photos from usb drive). Is there are sample code for using the AV External Storage api?

My iOS app can access the iphone media library, but if on Mac M4 is Error Domain=NSCocoaError Domain Code=257

Hello Apple, i've been using ios for many years and never had any issues with urdu language keyboard, but since the new 18.4 beta update some words are not working correctly as it should like a name of my friend who's name is "راعنیہ" but the new updated version cannot type is together and keep seperating like "راعنی ہ" its so frustrating to use like that and its not just one but so many other words that it just cannot do properly also the new font and no gap concept its hurting my eyes so much while reading or even typing.. i hope apple fixes that asap.. thankyou

Hi There, I have an app which access the media library, to save and load files. Since the IOS 18.2, the access to the media library stopped working. Now, I've noticed that our App doesn't show in the List of apps with access to Files ( Privacy & Security -> Files & Folders). Weird behavior is that, one iPhone with iOS 18.3.1 can access to the Files but others no, same iOS version 18.3.1. Test on Simulators (MAC) and works fine also. My info.plist file have the keys to access media library for long time and hasn't changed (at least in the las 4 years) including the key "Privacy - Media Library Usage Description". Also, I've noticed, that the message (popup) that request access to the media library, when using the app for the first time, doesn't show up anymore. We request access to the network (wifi) and this message still showing up but no the media library. I'm using Visual Studio with Xamarin on a MAC. I really appreciate any help you can because is very odd behavior and this started from the iOS 18.2.

Our iOS/AppleTV video content playback app uses AVPlayer to play HLS video streams and supports both custom and system playback UIs. The Fairplay content key is retrieved using AVContentKeySession. AirPlay is supported too. When the iPhone is connected to a TV through the lightning Apple Digital AV Adapter (A1438), the app is mirrored as expected. Problem: when using an iPhone or iPad on iOS 18.1.1, FairPlay-protected HLS streams are not played and a CoreMediaErrorDomain -12035 error is received by the AVPlayerItem. Also, once the issue has occurred, the mirroring freezes (the TV indefinitely displays the app playback screen) although the app works fine on the iOS device. The content key retrieval works as expected (I can see that 2 content key requests are made by the system by the way, probably one for the local playback and one for the adapter, as when AirPlaying) and the error is thrown after providing the AVContentKeyResponse. Unfortunately, and as far as I know, there is not documentation on CoreMediaErrorDomain errors so I don't know what -12035 means. The issue does not occur: on an iPhone on iOS 17.7 (even with FairPlay-protected HLS streams) when playing DRM-free video content (whatever the iOS version) when using the USB-C AV Adapter (whatever the iOS version) Also worth noting: the issue does not occur with other video playback apps such as Apple TV or Netflix although I don't have any details on the kind of streams these apps play and the way the FairPlay content key is retrieved (if any) so I don't know if it is relevant.

operation couldn't be completed. (CoreMediaErrorDomain error -42709.) this error shows after update He has been coming here for the last 10 days. Please! please correct it as soon as possible

On an iOS 18 phone, I use AVCaptureSession to capture HDR with x420 format. The output CMSampleBuffer is HLG colorspace, the propagated attachments contain kCVImageBufferAmbientViewingEnvironmentKey and kCVImageBufferSceneIlluminationKey. Now I use CAMetalLayer to render the CVPixelBuffer to the screen, but the brightness is brighter than AVSampleBufferDisplayLayer. Here is my code. - (void)_updateColorSpaceIfNeed:(CVPixelBufferRef)pixelBuffer { CAMetalLayer *layer = (CAMetalLayer *)_mtkView.layer; if (![layer isKindOfClass:CAMetalLayer.class]) return; layer.wantsExtendedDynamicRangeContent = YES; CFDataRef ambientViewingEnvironment = (CFDataRef)CVBufferCopyAttachment(pixelBuffer, kCVImageBufferAmbientViewingEnvironmentKey, NULL); NSData *data = (__bridge NSData *)ambientViewingEnvironment; if (ambientViewingEnvironment) CFRelease(ambientViewingEnvironment); CAEDRMetadata *metadata = [CAEDRMetadata HLGMetadataWithAmbientViewingEnvironment:data]; // CAEDRMetadata *metadata = [CAEDRMetadata HLGMetadata]; layer.EDRMetadata = metadata; layer.pixelFormat = MTLPixelFormatRGBA16Float; CGColorSpaceRef colorspace = CGColorSpaceCreateWithName(kCGColorSpaceITUR_2100_HLG); layer.colorspace = colorspace; if (colorspace) CGColorSpaceRelease(colorspace); } Why does the CAEDRMetadata class have "HLGMetadataWithAmbientViewingEnvironment:" and "HLGMetadata" methods, but does not provide the "HLGMetadataWithAmbientViewingEnvironment:sceneIllumination" method? I want to know how kCVImageBufferAmbientViewingEnvironmentKey and kCVImageBufferSceneIlluminationKey affect tone mapping. Is there any documentation I can refer to?

I found some documentation about Kext, but I heard they have now moved to Dext. So I was wondering if Dext could completely imitate the previous Kext. https://developer.apple.com/documentation/kernel/implementing_drivers_system_extensions_and_kexts This page is written like this Important In macOS 11 and later, the kernel doesn’t load a kext if an equivalent DriverKit solution exists. You may continue to use kexts in macOS 10.15 and earlier.

I am playing the protected HLS streams and the authorization token expires in 3 minutes. I am trying to achieve this with 'AVAssetResourceLoaderDelegate'. I can refresh the token and play it, but the problem is in between the session, the player stalls for a small time, LIKE 1 SECOND. Here's my code : class APLCustomAVARLDelegate: NSObject, AVAssetResourceLoaderDelegate { static let httpsScheme = "https" static let redirectErrorCode = 302 static let badRequestErrorCode = 400 private var token: String? private var retryDictionary = [String: Int]() private let maxRetries = 3 private func schemeSupported(_ scheme: String) -> Bool { let supported = ishttpSchemeValid(scheme) print("Scheme '\(scheme)' supported: \(supported)") return supported } private func reportError(loadingRequest: AVAssetResourceLoadingRequest, error: Int) { let nsError = NSError(domain: NSURLErrorDomain, code: error, userInfo: nil) print("Reporting error: \(nsError)") loadingRequest.finishLoading(with: nsError) } // Handle token renewal requests to prevent playback stalls func resourceLoader(_ resourceLoader: AVAssetResourceLoader, shouldWaitForRenewalOfRequestedResource renewalRequest: AVAssetResourceRenewalRequest) -> Bool { print("Resource renewal requested for URL: \(renewalRequest.request.url?.absoluteString ?? "unknown URL")") // Handle renewal the same way we handle initial requests guard let scheme = renewalRequest.request.url?.scheme else { print("No scheme found in the renewal URL.") return false } if isHttpsSchemeValid(scheme) { return handleHttpsRequest(renewalRequest) } print("Scheme not supported for renewal.") return false } private func isHttpsSchemeValid(_ scheme: String) -> Bool { let isValid = scheme == APLCustomAVARLDelegate.httpsScheme print("httpsScheme scheme '\(scheme)' valid: \(isValid)") return isValid } private func generateHttpsURL(sourceURL: URL) -> URL? { // If you need to modify the URL, do it here // Currently this just returns the same URL let urlString = sourceURL.absoluteString print("Generated HTTPS URL: \(urlString)") return URL(string: urlString) } private func handleHttpsRequest(_ loadingRequest: AVAssetResourceLoadingRequest) -> Bool { print("Handling HTTPS request.") guard let sourceURL = loadingRequest.request.url, var redirectURL = generateHttpsURL(sourceURL: sourceURL) else { print("Failed to generate HTTPS URL.") reportError(loadingRequest: loadingRequest, error: APLCustomAVARLDelegate.badRequestErrorCode) return true } // Track retry attempts with a dictionary keyed by request URL let urlString = sourceURL.absoluteString let currentRetries = retryDictionary[urlString] ?? 0 if currentRetries < maxRetries { retryDictionary[urlString] = currentRetries + 1 } else { // Too many retries, report a more specific error reportError(loadingRequest: loadingRequest, error: NSURLErrorTimedOut) retryDictionary.removeValue(forKey: urlString) return true } if var urlComponents = URLComponents(url: redirectURL, resolvingAgainstBaseURL: false) { var queryItems = urlComponents.queryItems ?? [] // Generate a fresh token each time let freshToken = AESTimeBaseEncription.secureEncryptSecretText() // Check if the token already exists if let existingTokenIndex = queryItems.firstIndex(where: { $0.name == "token" }) { // Update the existing token queryItems[existingTokenIndex].value = freshToken } else { // Add the token if it doesn't exist queryItems.append(URLQueryItem(name: "token", value: freshToken)) } urlComponents.queryItems = queryItems redirectURL = urlComponents.url! } let redirectRequest = URLRequest(url: redirectURL) let response = HTTPURLResponse(url: redirectURL, statusCode: APLCustomAVARLDelegate.redirectErrorCode, httpVersion: nil, headerFields: nil) print("Redirecting HTTPS to URL: \(redirectURL)") loadingRequest.redirect = redirectRequest loadingRequest.response = response loadingRequest.finishLoading() // If successful, reset the retry counter if retryDictionary[urlString] == maxRetries { retryDictionary.removeValue(forKey: urlString) } return true } }

Issue: Under certain conditions, using CallKit does not automatically enable the microphone. Steps to Reproduce: 1.Start an outgoing call, then the user manually mutes the audio. 2.Receive a native incoming call, end the current call, then answer the new incoming call.(This order is important.) 3.End the incoming call. 4.Start another outgoing call and observe the microphone; do not manually mute or unmute. Actual Behavior: The audio icon indicates that the audio is unmuted, but the microphone remains off, and the small yellow dot in the top status bar (which represents the microphone) does not appear. Expected Behavior: The microphone should be on, consistent with the audio icon display, and the small yellow dot should appear in the top status bar. Device: iPhone 16 pro & iPhone 15 pro, iOS 18.0+ Can it be reproduced using speakerbox(CallKit Demo)? YES

Hello! I am trying to determine the best approach with AVPlayer for implementing auto-play, that is, playback that automatically starts without user initiation. Ideally this would work for both local and streaming audio. My current approach is using KVO and the status on an AVPlayerItem equal to readyToPlay to do this, but I was wondering if there was a better property or state to use, or, alternatively, whether this use case may already be handled when automaticallyWaitsToMinimizeStalling is true, so that I could simply write: player.replaceCurrentItem(with: AVPlayerItem(url: streamingUrl)) player.rate = 1 or let playerItem = AVPlayerItem(url: streamingUrl) player = AVPlayer(playerItem: playerItem) player.rate = 1 and expect the item to be auto-played when ready. In the context of user-initiated playback, I've typically seen code that makes a button's enabled state contingent on player.currentItem.duration, e.g. in AVFoundationSimplePlayer-iOS. On the other hand, AVAutoWait, which utilizes automaticallyWaitsToMinimizeStalling, does not seem to do this. As a side note, I am not using an AVQueuePlayer.

I've been trying to use AVMIDIControlChangeEvent with a bankSelect message type to change the instrument the sequencer uses on a AVMusicTrack with no luck. I started with the Apple AVAEMixerSample, converting the initial setup/loading and portions dealing with the sequencer to Swift. I got that working and playing the "bluesyRiff" and then modified it to play individual notes. So my createAndSetupSequencer looked like func createAndSetupSequencer() { sequencer = AVAudioSequencer(audioEngine: engine) // guard let midiFileURL = Bundle.main.url(forResource: "bluesyRiff", withExtension: "mid") else { // print (" failed guard trying to get URL for bluesyRiff") // return // } let track = sequencer.createAndAppendTrack() var currTime = 1.0 for i: UInt32 in 0...8 { let newNoteEvent = AVMIDINoteEvent(channel: 0, key: 60+i, velocity: 64, duration: 2.0) track.addEvent(newNoteEvent, at: AVMusicTimeStamp(currTime)) currTime += 2.0 } The notes played, so then I also replaced the gs_instruments sound bank with GeneralUser GS MuseScore v1.442 first by trying guard let soundBankURL = Bundle.main.url(forResource: "GeneralUser GS MuseScore v1.442", withExtension: "sf2") else { return} do { try sampler.loadSoundBankInstrument(at: soundBankURL, program: 0x001C, bankMSB: 0x79, bankLSB: 0x08) } catch{.... } This appears to work, the instrument (8 which is "Funk Guitar") plays. If I change to bankLSB: 0x00 I get the "Palm Muted guitar". So I know that the soundfont has these instruments Stuff goes off the rails when I try to change the instruments in createAndSetupSequencer. Putting let programChange = AVMIDIProgramChangeEvent(channel: 0, programNumber: 0x001C) let bankChange = AVMIDIControlChangeEvent(channel: 0, messageType: AVMIDIControlChangeEvent.MessageType.bankSelect, value: 0x00) track.addEvent(programChange, at: AVMusicTimeStamp(1.0)) track.addEvent(bankChange, at: AVMusicTimeStamp(1.0)) just before my add note loop doesn't produce any change. Loading bankLSB 8 (Funk) in sampler.loadSoundBankInstrument and trying to change with bankSelect 0 (Palm muted) in createAndSetupSequencer results in instrument 8 (Funk) playing not Palm Muted. Loading bankLSB 0 (Palm muted) and trying to change with bankSelect 8 (Funk) doesn't work, 0 (Palm muted) plays I also tried sampler.loadInstrument(at: soundBankURL) and then I always get the first instrument in the sound font file (piano)no matter what values I put in my programChange/bankChange I've also changed the time in the track.addEvent to be 0, 1.0, 3.0 etc to no success The sampler.loadSoundBankInstrument specifies two UInt8 parameters, bankMSB and BankLSB while the AVMIDIControlChangeEvent bankSelect value is UInt32 suggesting it might be some combination of bankMSB and BankLSB. But the documentation makes no mention of what this should look like. I tried various combinations of 0x7908, 0X0879 etc to no avail I will also point out that I am able to successfully execute other control change events For example adding if i == 1 { let portamentoOnEvent = AVMIDIControlChangeEvent(channel: 0, messageType: AVMIDIControlChangeEvent.MessageType.portamento, value: 0xFF) track.addEvent(portamentoOnEvent, at: AVMusicTimeStamp(currTime)) let portamentoRateEvent = AVMIDIControlChangeEvent(channel: 0, messageType: AVMIDIControlChangeEvent.MessageType.portamentoTime, value: 64) track.addEvent(portamentoRateEvent, at: AVMusicTimeStamp(currTime)) } does produce a change in the sound. (As an aside, a definition of what portamento time is, other than "the rate of portamento" would be welcome. is it notes/seconds? freq/minute? beats/hour?) I was able to get the instrument to change in a different program using MusicPlayer and a series of MusicTrackNewMIDIChannelEvent on a track but these operate on a MusicTrack not the AVMusicTrack which the sequencer uses. Has anyone been successful in switching instruments through an AVMIDIControlChangeEvent or have any feedback on how to do this?

Hi, I am recording a video at 240 FPS within my application and saving it to the Photos app. The recorded video retains 240 FPS in the Photos app. However, after trimming the video using the Photos app and importing it back into my app, the FPS is reduced to 30 FPS. Steps to Reproduce: Record a video inside the application at 240 FPS. Save the recorded video to the Photos app. Verify that the video retains 240 FPS in the Photos app. Trim the video using the built-in Photos app editor. Import the trimmed video back into the application. The FPS of the imported video is now reduced to 30 FPS. Code Used for Importing Video: I am using the following code to fetch the video from the Photos app: let options: PHVideoRequestOptions = PHVideoRequestOptions() options.version = .current // Using `.original` preserves FPS, but I need `.current` for other changes options.deliveryMode = .highQualityFormat options.isNetworkAccessAllowed = true PHImageManager.default().requestAVAsset(forVideo: self, options: options) { (avAsset, audioMix, info) in if let urlAsset = avAsset as? AVURLAsset { completionHandler(urlAsset.url, self) } else { self.askForOriginal(completionHandler: completionHandler) } } Observations: The original video retains 240 FPS until it is trimmed in the Photos app. After trimming, the FPS automatically drops to 30 FPS when imported back into the app. If I use options.version = .original, the FPS is preserved, but I need .current to apply other modifications. Questions: Is this an expected behavior of PHImageManager when requesting a video with options.version = .current? Is there a way to preserve the original FPS while still using .current? Are there any workarounds to extract the trimmed video without FPS reduction? Any insights or solutions would be greatly appreciated. Thanks in advance!

When building an application that can be built on iOS using macCatalyst, a link error like the one below will occur. Undefined symbol: OBJC_CLASS$_AVPlayerViewController The AVPlayerViewController documentation seems to support macCatalyst, but what is the reality? [AVPlayerViewController](https://developer.apple.com/documentation/avkit/avplayerviewcontroller? language=objc) Each version of the environment is as follows. Xcode 16.2 macOS deployment target: macOS 10.15 iOS deployment target: iOS 13.0 Thank you for your support.

Hello, I am having difficulties with configuring MusicKit correctly for my web app that I am building, seeking assistance with the issues I am having. Would greatly appreciate any help! After allowing access to the following, "Access Request media.mydomain.com would like to access Apple Music, media library, and listening activity for myemail'@icloud.com.", I get a popup error that states, "Authorization failed. Please try again.". Following is the information that is given in developer console: [Error] Failed to load resource: the server responded with a status of 403 () (webPlayerLogout, line 0) [Error] Authorization failed: AUTHORIZATION_ERROR: Unauthorized (anonymous function) (media.mydomain.com:398)

I am using AVMulti so the user captures two images how can I access those images if there is only one url that stores the captured images for the lockScreenCapture extension ? Plus how can I detect if the user opened the app from the extension to be able to navigate the user to the right screen ?

Is it possible to play WebM audio on iOS? Either with AVPlayer, AVAudioEngine, or some other API? Safari has supported this for a few releases now, and I'm wondering if I missed something about how to do this. By default these APIs don't seem to work (nor does ExtAudioFileOpen). Our usecase is making it possible for iOS users to play back audio recorded in our webapp (desktop versions of Chrome & Firefox only support webm as a destination format for MediaRecorder)

Bug Report: ScreenCaptureKit System Audio Capture Crashes with EXC_BAD_ACCESS Summary When using ScreenCaptureKit to capture system audio for extended periods, the application crashes with EXC_BAD_ACCESS in Swift's error handling runtime. The crash occurs in swift_getErrorValue when trying to process an error from the SCStream delegate method didStopWithError. This appears to be a framework-level issue in ScreenCaptureKit or its underlying ReplayKit implementation. Environment macOS Sonoma 14.6.1 Swift 5.8 ScreenCaptureKit framework Detailed Description Our application captures system audio using ScreenCaptureKit's audio capture capabilities. After successfully capturing for several minutes (typically after 3-4 segments of 60-second recordings), the application crashes with an EXC_BAD_ACCESS error. The crash happens when the Swift runtime attempts to process an error in the SCStreamDelegate.stream(_:didStopWithError:) method. The crash consistently occurs in swift_getErrorValue when attempting to access the class of what appears to be a null object. This suggests that the error being passed from the system framework to our delegate method is malformed or contains invalid memory. Steps to Reproduce Create an SCStream with audio capture enabled Add audio output to the stream Start capture and write audio data to disk Allow the capture to run for several minutes (3-5 minutes typically triggers the issue) The app will crash with EXC_BAD_ACCESS in swift_getErrorValue Code Sample func stream(_ stream: SCStream, didStopWithError error: Error) { print("Stream stopped with error: \(error)") // Crash occurs before this line executes } func stream(_ stream: SCStream, didOutputSampleBuffer sampleBuffer: CMSampleBuffer, of type: SCStreamOutputType) { guard type == .audio, sampleBuffer.isValid else { return } // Process audio data... } Expected Behavior The error should be properly propagated to the delegate method, allowing for graceful error handling and recovery. Actual Behavior The application crashes with EXC_BAD_ACCESS when the Swift runtime attempts to process the error in swift_getErrorValue. Crash Log Details Thread #35, queue = 'com.apple.NSXPCConnection.m-user.com.apple.replayd', stop reason = EXC_BAD_ACCESS (code=1, address=0x0) frame #0: 0x0000000194c3088c libswiftCore.dylib`swift::_swift_getClass(void const*) + 8 frame #1: 0x0000000194c30104 libswiftCore.dylib`swift_getErrorValue + 40 frame #2: 0x00000001057fba30 shadow`NewScreenCaptureService.stream(stream=0x0000600002de6700, error=Swift.Error @ 0x000000016b7b5e30) at NEW+ScreenCaptureService.swift:365:15 frame #3: 0x00000001057fc050 shadow`@objc NewScreenCaptureService.stream(_:didStopWithError:) at <compiler-generated>:0 frame #4: 0x0000000219ec5ca0 ScreenCaptureKit`-[SCStreamManager stream:didStopWithError:] + 456 frame #5: 0x00000001ca68a5cc ReplayKit`-[RPScreenRecorder stream:didStopWithError:] + 84 frame #6: 0x00000001ca696ff8 ReplayKit`-[RPDaemonProxy stream:didStopWithError:] + 224 Printing description of stream._streamQueue: error: ObjectiveC.id:4294967281:18: note: 'id' has been explicitly marked unavailable here public typealias id = AnyObject ^ error: /var/folders/v4/3xg1hmp93gjd8_xlzmryf_wm0000gn/T/expr23-dfa421..cpp:1:65: 'id' is unavailable in Swift: 'id' is not available in Swift; use 'Any' Swift._DebuggerSupport.stringForPrintObject(Swift.UnsafePointer<id>(bitPattern: 0x104ae08c0)!.pointee) ^~ ObjectiveC.id:2:18: note: 'id' has been explicitly marked unavailable here public typealias id = AnyObject ^ warning: /var/folders/v4/3xg1hmp93gjd8_xlzmryf_wm0000gn/T/expr23-dfa421..cpp:5:7: initialization of variable '$__lldb_error_result' was never used; consider replacing with assignment to '_' or removing it var $__lldb_error_result = __lldb_tmp_error ~~~~^~~~~~~~~~~~~~~~~~~~ _ Before the crash, we observed this error message in the console: [ERROR] *****SCStream*****RemoteAudioQueueOperationHandlerWithError:1015 Error received from the remote queue -16665 Additional Context The issue occurs consistently after approximately 3-4 successful audio segment recordings of 60 seconds each Commenting out custom segment rotation logic does not prevent the crash The crash involves XPC communication with Apple's ReplayKit daemon The error appears to be corrupted or malformed when crossing the XPC boundary Workarounds Attempted Added proper thread safety for all published properties using DispatchQueue.main.async Implemented more robust error handling in the delegate methods None of these approaches prevented the crash since it occurs at the Swift runtime level before our code executes. Impact This issue prevents reliable long-duration audio capture using ScreenCaptureKit. This bug significantly limits the usefulness of ScreenCaptureKit for any application requiring continuous system audio capture for more than a few minutes. Perhaps this issue might be related to a macOS bug where the system dialog indicates that the screen is being shared, even though nothing is actually being shared. Moreover, when attempting to stop sharing, nothing happens.

I have been using SDAVAssetExportSession to compress videos in an app I am building, everything goes very smoothly until I have my new Iphone16, on the device, the spatial audio in camera setting is turned on by default, then the SDAVAssetExportSession starts to fail. I know it has something to do with audioSetting. the current setting is something like this: exportSession.audioSettings = [ AVFormatIDKey: kAudioFormatMPEG4AAC, AVNumberOfChannelsKey: 2, AVSampleRateKey: 44100, AVEncoderBitRateKey: 128000 ] And also, this is passed to the underlying object AVAssetReader or AVAssetWriter. I am not experienced in this area, and I really had a hard time trying to figure out. Does anyone know how to set up AVAssetReader or AVAssetWriter to process video with spatial audio tracks ? thanks in advance.