I’m implementing a custom playback pipeline using AVSampleBufferAudioRenderer together with AVSampleBufferRenderSynchronizer. hasSufficientMediaDataForReliablePlaybackStart appears to be the intended signal for determining when enough media has been queued to start playback. For local playback, this works well in practice — the property becomes true after a reasonable amount of media is enqueued. However, when the output route is AirPlay, using this property becomes difficult: AirPlay requires significantly more buffered media before the renderer reports sufficient data. The required preroll amount is much larger than for local playback. For short assets, it is possible to enqueue the entire audio track and still never observe hasSufficientMediaDataForReliablePlaybackStart == true. In that situation there is no more media data to enqueue, but the renderer still reports that playback is not ready. Given this behavior, what is the recommended way to determine playback readiness when using AVSampleBufferAudioRenderer with AirPlay?

Hello, I’m building an iOS video player using AVPlayer and a custom playback queue. I implemented remote controls using MPRemoteCommandCenter and enabled: nextTrackCommand previousTrackCommand playCommand pauseCommand I disabled: skipForwardCommand skipBackwardCommand seekForwardCommand seekBackwardCommand I also set queue metadata in MPNowPlayingInfoCenter: MPNowPlayingInfoPropertyPlaybackQueueIndex MPNowPlayingInfoPropertyPlaybackQueueCount Even with these commands enabled and the queue count greater than 1, the iOS lock screen continues to display the 10-second skip buttons instead of the previous/next track buttons. The commands themselves work correctly when triggered externally (Control Center, headphones, etc.), but the UI still shows the skip controls. Is there a way to force the lock screen UI to display previous / next track buttons for a video playlist? Or is this behavior expected when using AVPlayer with video content? Thanks.

Hello everyone, I’m looking for more detailed information regarding UVC (USB Video Class) over MFi within the Apple ecosystem and would appreciate some clarification. I’m interested in developing (or interfacing with) an accessory that transmits video over USB using the UVC standard, and I’d like to better understand how this works within the MFi (Made for iPhone) program. Here are my main questions: 1. Do iOS devices provide native support for UVC over USB-C or Lightning within the MFi framework? 2. Are there any specific firmware or authentication requirements when the accessory is MFi-certified? 3. Does UVC support depend solely on the hardware interface (USB-C vs Lightning), or are there additional software-level requirements? 4. Is there any official documentation outlining the recommended flow for implementing UVC-based video capture accessories on iOS? From what I understand, USB-C iPads appear to offer more direct support for standard UVC devices, but it’s not entirely clear how this integrates with the MFi ecosystem with iOS, especially for commercial product development. If anyone has gone through this process or can point me to relevant technical documentation, I would greatly appreciate the guidance. Thank you!

Hi, I’m trying to better understand how AVAssetDownloadConfiguration selects video variants when downloading HLS content for offline playback. Suppose I have an HLS master playlist (.m3u8) that contains several video variants defined with #EXT-X-STREAM-INF. For example, the master playlist may contain multiple video streams like this: Same resolution, different BANDWIDTH Or different resolutions (for example 720p, 1080p, etc.) My question is: How many video variants are actually downloaded when using AVAssetDownloadConfiguration without specifying any variantQualifiers? In other words: If the master playlist contains multiple video variants, will the download task fetch only one variant, or multiple variants? Does the behavior differ depending on whether the variants differ only by BANDWIDTH or also by RESOLUTION? What I observed in testing In my tests, I always end up with only one video variant downloaded, specifically the one with the highest BANDWIDTH parameter. In the m3u8 files I tested, all video variants had identical parameters (resolution, codec, frame rate, etc.) and differed only by the BANDWIDTH attribute in the master playlist. However, when inspecting the downloaded .movpkg, I noticed something interesting in boot.xml. It lists two video streams: one with complete="true" (the one with highest bandwidth) another with complete="no" (the one with lowest bandwidth) I actually had 3 video streams listed in m3u8, but the one with middle bandwidth wasn't listed in boot.xml file at all. There are also additional streams for audio and subtitles in boot.xml file. This made me wonder whether the system initially attempts to download another video variant (possibly a lower bitrate one), but then switches to the highest-quality variant and only completes that one. Additional question about variantQualifiers If I provide a predicate such as: NSPredicate(format: "peakBitRate > 0") which should theoretically match all variants, will the download task attempt to download all matching video variants, or will it still select only one? Summary So the main questions are: Without variantQualifiers, does AVAssetDownloadConfiguration always download a single video variant, and if so, how is it chosen? Does the behavior differ if variants have different resolutions vs only different bitrates? When a predicate matches multiple variants, can multiple video variants actually be downloaded in a single .movpkg? Why might boot.xml list multiple video streams when only one appears to be fully downloaded? Any clarification on the intended behavior would be greatly appreciated. Thanks!

In Instruments, I'm seeing "Zero Time Stamp" events in the "Audio Server" lane. What does that mean?

In iOS 26, AVSpeechSynthesizer read Mandarin into Cantonese pronunciation. No matter how you set the language, and change the settings of my phone system, it doesn't work. let utterance = AVSpeechUtterance(string: "你好啊") //let voice = AVSpeechSynthesisVoice(language: "zh-CN") // not work let voice = AVSpeechSynthesisVoice(language: "zh-Hans") // not work too utterance.voice = voice et synth = AVSpeechSynthesizer() synth.speak(utterance)

Please include the line below in follow-up emails for this request. Case-ID: 11089799 When using AVSpeechUtterance and setting it to play in Mandarin, if Siri is set to Cantonese on iOS 18, it will be played in Cantonese. There is no such issue on iOS 17 and 16. 1.let utterance = AVSpeechUtterance(string: textView.text) let voice = AVSpeechSynthesisVoice(language: "zh-CN") utterance.voice = voice 2.In the phone settings, Siri is set to Cantonese

My code that streams buffers into AVAudioPlayerNode is stuttering when the buffer is finished and before the next one is played. while engine.isRunning { let framesToCopy = min(buffer.frameLength - framePosition, Self.BufferSize) let srcRaw = UnsafeRawPointer(srcPtr) let playbackBuffer = AVAudioPCMBuffer(pcmFormat: buffer.format, frameCapacity: Self.BufferSize)! let playbackPtr = playbackBuffer.floatChannelData![0] let destRaw = UnsafeMutableRawPointer(mutating: playbackPtr) memcpy(destRaw, srcRaw, Int(framesToCopy) * MemoryLayout<Float>.stride) srcPtr = srcPtr.advanced(by: Int(framesToCopy)) playbackBuffer.frameLength = framesToCopy await player.scheduleBuffer(playbackBuffer, at: nil, options: [], completionCallbackType: .dataRendered) } I've tried to schedule multiple buffers at once using a combination of both the synchronous and async versions of scheduleBuffer because I thought the delay might be but it still stutters and the data copied into the playbackBuffer matches the source buffer. I've tried all combinations of options and completionCallbackType but no luck. I've tried increasing the buffer size but that just spaces out the stutters because the buffer is larger. What am I missing about this API?

Hi everyone, We’re encountering an issue where AudioQueueNewOutput blocks indefinitely and never returns, and we’re hoping to get some insight or confirmation if this is a known behavior/regression on newer iOS versions. Issue Description When triggering audio playback, we create an output AudioQueue using AudioQueueNewOutput. On some devices, the call hangs inside AudioQueueNewOutput and never returns, with no OSStatus error and no subsequent logs. This behavior is reproducible mainly on iOS 18.3. Earlier iOS versions do not show this issue under the same code path. if (audioDes) { mAudioDes.mSampleRate = audioDes->mSampleRate; mAudioDes.mBitsPerChannel = audioDes->mBitsPerChannel; mAudioDes.mChannelsPerFrame = audioDes->mChannelsPerFrame; mAudioDes.mFormatID = audioDes->mFormatID; mAudioDes.mFormatFlags = audioDes->mFormatFlags; mAudioDes.mFramesPerPacket = audioDes->mFramesPerPacket; mAudioDes.mBytesPerFrame = audioDes->mBytesPerFrame; mAudioDes.mBytesPerPacket = audioDes->mBytesPerFrame; mAudioDes.mReserved = 0; } // Create AudioQueue for output OSStatus status = AudioQueueNewOutput( &mAudioDes, AQOutputCallback, this, NULL, NULL, 0, &audioQueue ); code-block The thread blocks inside AudioQueueNewOutput, and execution never reaches the next line. Additional Notes / Observations ASBD is confirmed to be valid Standard PCM output Sample rate, channels, bytes per frame/packet all consistent Same ASBD works correctly on earlier iOS versions AudioQueue is created on a background thread Not on the main thread Not inside the AudioQueue callback On first creation, AVAudioSession may not yet be active setCategory and setActive:YES may be called shortly before creating the AudioQueue There may be a timing window where the session is still activating Issue is reported mainly on iOS 18.3 Multiple user reports point to iOS 18.3 devices Same code path works on iOS 17.x and earlier No OSStatus error is returned — the call simply never returns. Questions Is it expected that AudioQueueNewOutput can block indefinitely while waiting for AVAudioSession / audio route / HAL readiness? Have there been any behavior changes in iOS 18.3 regarding AudioQueue creation or AudioSession synchronization? Is it unsafe to call AudioQueueNewOutput before AVAudioSession is fully active on recent iOS versions? Are there recommended patterns (or delays / callbacks) to ensure AudioQueue creation does not hang? Any insight or confirmation would be greatly appreciated. Thanks in advance!

I read somewhere that the frames are returned in decode order instead of presentation order when using AVAssetReader. The documentation seems sparse on the subject. I have so far failed to find a video file where the frames are not returned in presentation order. Can anyone confirm the frames are actually returned in decode order?

Hello, I am currently developing a live streaming application using AVPlayer to play LL-HLS (Low-Latency HLS) content. During our testing phase, we consistently encountered the following error in the logs: CoreMediaErrorDomain Code=-15517 The challenge we are facing is that the error description is quite vague. It only provides cryptic messages such as "Key not found" or "No value information," which makes it extremely difficult to identify the root cause or perform a deep-dive analysis. I have searched through the official Apple Developer documentation and technical notes, but I couldn’t find any specific reference to what Code -15517 signifies in the context of LL-HLS or CoreMedia. Regarding this issue, I have the following questions: What is the specific meaning of this error code (-15517)? Does it relate to missing tags in the HLS manifest, or is it an internal state issue within the AVPlayer stack? Specifically, I would like to know if this is a critical error that disrupts playback, or if it is just a warning that can be safely ignored. Is there any additional logging or debugging tool you would recommend to further investigate "Key not found" issues in LL-HLS? Any insights or guidance from the community or Apple engineers would be greatly appreciated. Thank you in advance for your help.

I just bought a monitor S2725QC from Dell Technologies and isn't fully-integrated with MacOS even though it says on the website it is compatible with MacOS. https://www.dell.com/en-us/shop/all-monitors/sac/monitors/all-monitors/macos-compatible?appliedRefinements=51765 The screen brightness and volume control buttons don't work with the monitors (I have two). What can I do in terms of writing code with Dell Monitor SDK and MacOS Frameworks/Technologies?

I want to: Run ARKit on the main rear camera, and while it's running shoot high resolution pictures on the wide camera, without disturbing the AR tracking. Is this possible?

I'm relatively new to Swift development (and native iOS development for that matter) I've got an iOS app that uses the iPhone / iPad built in cameras, and am looking to make this more compatible with macOS. Using the normal AVCaptureDevice.DiscoverySession I seem to get the iPhone Continuity Camera and the in-built MacBook Pro camera but I don't see other input devices that I see in QuickTime Player (for example) such as connected external cameras or Virtual Inputs provided by NDI Virtual Input and OBS. Is there a way to see access these without a specific Mac build (as the rest of the functionality works great, and I'd rather not diverge the codebase too much as it's easier to update one app than two!

I’m building a teleprompter-style app that relies on Picture in Picture. PiP starts correctly on device. Everything works — until another app (e.g. TikTok / Instagram) starts active video recording. When camera capture begins in the foreground app, iOS terminates my PiP session. Some teleprompter apps appear to keep PiP active while recording in other apps, so I’m trying to understand the recommended architectural pattern for this scenario. Is there a documented approach or best practice to keep PiP stable during third-party camera capture? Looking specifically for guidance on the correct AVKit / AVAudioSession configuration for this use case.

According to the documentation (https://developer.apple.com/documentation/avfoundation/avcontentkeyrequest/originatingrecipient?changes=_3&language=objc), starting with ios 18.4, I can get AVContentKeyRecipient from AVContentKeyRequest. But when I try to get it, I get a crash. What could be the issue? I want to note that I add the asset to the AVContentKeySession using the addContentKeyRecipient method (https://developer.apple.com/documentation/avfoundation/avcontentkeysession/addcontentkeyrecipient(_:)?changes=_3&language=objc).

VideoMaterial Black Screen on Vision Pro Device (Works in Simulator) App Overview App Name: Extn Browser Bundle ID: ai.extn.browser Purpose: A visionOS web browser that plays 360°/180° VR videos in an immersive sphere environment Development Environment & SDK Versions Component Version Xcode 26.2 Swift 6.2 visionOS Deployment Target 26.2 Swift Concurrency MainActor isolation enabled App is released in the TestFlight. Frameworks Used SwiftUI - UI framework RealityKit - 3D rendering, MeshResource, ModelEntity, VideoMaterial AVFoundation - AVPlayer, AVAudioSession WebKit - WKWebView for browser functionality Network - NWListener for local proxy server Sphere Video Mechanism The app creates an immersive 360° video experience using the following approach: // 1. Create sphere mesh (10 meter radius for immersive viewing) let mesh = MeshResource.generateSphere(radius: 10.0) // 2. Create initial transparent material var material = UnlitMaterial() material.color = .init(tint: .clear) // 3. Create entity and invert sphere (negative X scale) let sphere = ModelEntity(mesh: mesh, materials: [material]) sphere.scale = SIMD3<Float>(-1, 1, 1) // Inverts normals for inside-out viewing sphere.position = SIMD3<Float>(0, 1.5, 0) // Eye level // 4. Create AVPlayer with video URL let player = AVPlayer(url: videoURL) // 5. Configure audio session for visionOS let audioSession = AVAudioSession.sharedInstance() try audioSession.setCategory(.playback, mode: .moviePlayback, options: [.mixWithOthers]) try audioSession.setActive(true) // 6. Create VideoMaterial and apply to sphere let videoMaterial = VideoMaterial(avPlayer: player) if var modelComponent = sphere.components[ModelComponent.self] { modelComponent.materials = [videoMaterial] sphere.components.set(modelComponent) } // 7. Start playback player.play() ImmersiveSpace Configuration // browserApp.swift ImmersiveSpace(id: appModel.immersiveSpaceID) { ImmersiveView() .environment(appModel) } .immersionStyle(selection: .constant(.mixed), in: .mixed) Entitlements <!-- browser.entitlements --> <key>com.apple.security.app-sandbox</key> <true/> <key>com.apple.security.network.client</key> <true/> <key>com.apple.security.network.server</key> <true/> Info.plist Network Configuration <key>NSAppTransportSecurity</key> <dict> <key>NSAllowsArbitraryLoads</key> <true/> </dict> The Issue Behavior in Simulator: Video plays correctly on the inverted sphere surface - 360° video is visible and wraps around the user as expected. Behavior on Physical Vision Pro: The sphere displays a black screen. No video content is visible, though the sphere entity itself is present. Important: Not a DRM/Licensing Issue This issue is NOT related to Digital Rights Management (DRM) or FairPlay. I have tested with: Unlicensed raw MP4 video files (no DRM protection) Self-hosted video content with no copy protection Direct MP4 URLs from CDN without any licensing requirements The same black screen behavior occurs with all unprotected video sources, ruling out DRM as the cause. (Plain H.264 MP4, no DRM) Screen Recording: Working in Simulator The following screen recording demonstrates playing a 360° YouTube video in the immersive sphere on the visionOS Simulator: https://cdn.commenda.kr/screen-001.mov This confirms that the VideoMaterial and sphere rendering work correctly in the simulator, but the same setup shows a black screen on the physical Vision Pro device. Observations AVPlayer status reports .readyToPlay - The video appears to load successfully VideoMaterial is created without errors - No exceptions thrown Sphere entity renders - The geometry is visible (black surface) Audio session is configured - No errors during audio session setup Network requests succeed - The video URL is accessible from the device Same result with local/unprotected content - DRM is not a factor Console Logs (Device) The logging shows: Sphere created and added to scene AVPlayer created with correct URL VideoMaterial created and applied Player status transitions to .readyToPlay player.play() called successfully Rate shows 1.0 (playing) Despite all success indicators, the rendered output is black. Questions for Apple Are there known differences in VideoMaterial behavior between the visionOS Simulator and physical Vision Pro hardware? Does VideoMaterial(avPlayer:) require specific video codec/format requirements that differ on device? (The test video is a standard H.264 MP4) Is there a required Metal capability or GPU feature for VideoMaterial that may not be available in certain contexts on device? Does the immersion style (.mixed) affect VideoMaterial rendering on hardware? Are there additional entitlements required for video texture rendering in RealityKit on physical hardware? Attempted Solutions Configured AVAudioSession with .playback category Added delay before player.play() to ensure material is applied Verified sphere scale inversion (-1, 1, 1) Tested multiple video URLs (including raw, unlicensed MP4 files) Confirmed network connectivity on device Ruled out DRM/FairPlay issues by testing unprotected content Environment Details Device: Apple Vision Pro visionOS Version: 26.2 Xcode Version: 26.2 macOS Version: Darwin 25.2.0

Dear Support Team, ​I am writing to seek technical assistance regarding a persistent issue with Dolby Vision exporting in DaVinci Resolve 20 on my iPad Pro 12.9-inch (2021, M1 chip) running iPadOS 26.0.1. ​The Issue: Despite correctly configuring the project for a Dolby Vision workflow and successfully completing the dynamic metadata analysis, the "Dolby Vision Profile" dropdown menu (and related embedding options) is completely missing from the Advanced Settings in the Deliver page. ​My Current Configuration & Steps Taken: ​Software Version: DaVinci Resolve Studio 20 (Studio features like Dolby Vision analysis are active and functional). ​Project Settings: Color Science: DaVinci YRGB Color Managed. ​Dolby Vision: Enabled (Version 4.0) with Mastering Display set to 1000 nits. ​Output Color Space: Rec.2100 ST2084. ​Color Page: Dynamic metadata analysis has been performed, and "Trim" controls are functional. ​Export Settings: ​Format: QuickTime / MP4. ​Codec: H.265 (HEVC). ​Encoding Profile: Main 10. ​The Problem: Under "Advanced Settings," there is no option to select a Dolby Vision Profile (e.g., Profile 8.4) or to "Embed Dolby Vision Metadata." ​Potential Variables: ​System Version: I am currently running iPadOS 26. ​Apple ID: My iPad is currently not logged into an Apple ID. I suspect this might be preventing the app from accessing certain system-level AVFoundation frameworks or Dolby DRM/licensing certificates required for metadata embedding. ​Could you please clarify if the "Dolby Vision Profile" option is dependent on a signed-in Apple ID for hardware-level encoding authorization, or if this is a known compatibility issue with the current iPadOS 26 build? ​I look forward to your guidance on how to resolve this. ​Best regards, INSOFT_Fred

I am unable to find any clearcut documentation on configuring AVCaptureSession pipeline to capture video with proResRAW codec type, which is 16 bit format. Is it supported only with AVCaptureMovieFileOutput or one can have AVCaptureVideoDataOutput emitting 16-bit sample buffers that can be vended to AVAssetWriter?

Hello, I have implemented Low-Latency Frame Interpolation using the VTFrameProcessor framework, based on the sample code from https://developer.apple.com/kr/videos/play/wwdc2025/300. It is currently working well for both LIVE and VOD streams. However, I have a few questions regarding the lifecycle management and synchronization of this feature: 1. Common Questions (Applicable to both Frame Interpolation & Super Resolution) 1.1 Dynamic Toggling Do you recommend enabling/disabling these features dynamically during playback? Or is it better practice to configure them only during the initial setup/preparation phase? If dynamic toggling is supported, are there any recommended patterns for managing VTFrameProcessor session lifecycle (e.g., startSession / endSession timing)? 1.2 Synchronization Method I am currently using CADisplayLink to fetch frames from AVPlayerItemVideoOutput and perform processing. Is CADisplayLink the recommended approach for real-time frame acquisition with VTFrameProcessor? If the feature needs to be toggled on/off during active playback, are there any concerns or alternative approaches you would recommend? 1.3 Supported Resolution/Quality Range What are the minimum and maximum video resolutions supported for each feature? Are there any aspect ratio restrictions (e.g., does it support 1:1 square videos)? Is there a recommended resolution range for optimal performance and quality? 2. Frame Interpolation Specific Questions 2.1 LIVE Stream Support Is Low-Latency Frame Interpolation suitable for LIVE streaming scenarios where latency is critical? Are there any special considerations for LIVE vs VOD? 3. Super Resolution Specific Questions 3.1 Adaptive Bitrate (ABR) Stream Support In ABR (HLS/DASH) streams, the video resolution can change dynamically during playback. Is VTLowLatencySuperResolutionScaler compatible with ABR streams where resolution changes mid-playback? If resolution changes occur, should I recreate the VTLowLatencySuperResolutionScalerConfiguration and restart the session, or does the API handle this automatically? 3.2 Small/Square Resolution Issue I observed that 144x144 (1:1 square) videos fail with error:   "VTFrameProcessorErrorDomain Code=-19730: processWithSourceFrame within VCPFrameSuperResolutionProcessor failed" However, 480x270 (16:9) videos work correctly. minimumDimensions reports 96x96, but 144x144 still fails. Is there an undocumented restriction on aspect ratio or a practical minimum resolution? 3.3 Scale Factor Selection supportedScaleFactors returns [2.0, 4.0] for most resolutions. Is there a recommended scale factor for balancing quality and performance? Are there scenarios where 4.0x should be avoided? The documentation on this specific topic seems limited, so I would appreciate any insights or advice. Thank you.