Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.

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Vision Framework VNTrackObjectRequest: Minimum Valid Bounding Box Size Causing Internal Error (Code=9)
I'm developing a tennis ball tracking feature using Vision Framework in Swift, specifically utilizing VNDetectedObjectObservation and VNTrackObjectRequest. Occasionally (but not always), I receive the following runtime error: Failed to perform SequenceRequest: Error Domain=com.apple.Vision Code=9 "Internal error: unexpected tracked object bounding box size" UserInfo={NSLocalizedDescription=Internal error: unexpected tracked object bounding box size} From my investigation, I suspect the issue arises when the bounding box from the initial observation (VNDetectedObjectObservation) is too small. However, Apple's documentation doesn't clearly define the minimum bounding box size that's considered valid by VNTrackObjectRequest. Could someone clarify: What is the minimum acceptable bounding box width and height (normalized) that Vision Framework's VNTrackObjectRequest expects? Is there any recommended practice or official guidance for bounding box size validation before creating a tracking request? This information would be extremely helpful to reliably avoid this internal error. Thank you!
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107
Apr ’25
iOS: Want to use USB client mode to send data.
I want my iOS app to be able to use USB client mode to send LiDAR data and camera frames to another device. What are my options for doing this. I've found IOUSBHost for host mode, but I want to see all my options. The device I want driving the bus is a Meta Quest 3, which, and I mention for the sake of clarity, is inherently an Android device. The iPhone is to be used as a sensor hub, sending data to the Quest 3 for further processing. As a workaround, I could let the iPhone drive the bus and have the Quest 3 use Android's accessory mode, which lets other devices drive the USB bus. But, there are more USB devices I want to attach for my project, and doing this makes such more difficult. I want to avoid it.
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314
Jan ’25
AVPlayer periodic time observer stops notifying when switching back from AirPlay to local playback
The app registers a periodic time observer to the AVPlayer when the playback starts and it works fine. When switching to AirPlay during playback, the periodic time observation continues working as expected. However, when switching back to local playback, the periodic time observer does not fire anymore until a seek is performed. The app removes the periodic time observer only when the playback stops. I can see that when switching back to local playback, the timeControlStatus successively changes to .waitingToPlayAtSpecifiedRate (reason: .evaluatingBufferingRate) then to .waitingToPlayAtSpecifiedRate (reason: .toMinimizeStalls) and finally to .playing But the time observation does not work anymore. Also, the issue is systematic with Live and VOD streams providing a program date (with HLS property #EXT-X-PROGRAM-DATE-TIME), with or without any DRM, and is never reproduced with other VOD streams.
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108
Apr ’25
Audio / Video sync issue on iOS using AVSampleBufferRenderSynchronizer
My current app implements a custom video player, based on a AVSampleBufferRenderSynchronizer synchronising two renderers: an AVSampleBufferDisplayLayer receiving decoded CVPixelBuffer-based video CMSampleBuffers, and an AVSampleBufferAudioRenderer receiving decoded lpcm-based audio CMSampleBuffers. The AVSampleBufferRenderSynchronizer is started when the first image (in presentation order) is decoded and enqueued, using avSynchronizer.setRate(_ rate: Float, time: CMTime), with rate = 1 and time the presentation timestamp of the first decoded image. Presentation timestamps of video and audio sample buffers are consistent, and on most streams, the audio and video are correctly synchronized. However on some network streams, on iOS, the audio and video aren't synchronized, with a time difference that seems to increase with time. On the other hand, with the same player code and network streams on macOS, the synchronization always works fine. This reminds me of something I've read, about cases where an AVSampleBufferRenderSynchronizer could not synchronize audio and video, causing them to run with independent and potentially drifting clocks, but I cannot find it again. So, any help / hints on this sync problem will be greatly appreciated! :)
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1.2k
Apr ’25
Custom Share Desination stopped working in FCP X 11
We integrate with FCP X using a custom share destination and the Apple Script interface. This has been working fine until the the recent version 11 update of FCP X. With this update we are no longer receiving the open event when the export has completed. We get the apple event to creat the Asset and the file is exported to the location we set in the response. There is just no open event after that. I suspect something is wrong with our scripting support but I have no idea what or how to troubleshoot. This works fine in 10.8.1 and below.
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378
Dec ’24
App recedes to background,audioEngine.start()
private var audioEngine = AVAudioEngine() private var inputNode: AVAudioInputNode! func startAnalyzing() { inputNode = audioEngine.inputNode let recordingFormat = inputNode.outputFormat(forBus: 0) let hardwareSampleRate = recordingSession.sampleRate inputNode.removeTap(onBus: 0) if recordingFormat.sampleRate != hardwareSampleRate { print("。") let newFormat = AVAudioFormat(commonFormat: recordingFormat.commonFormat, sampleRate: hardwareSampleRate, channels: recordingFormat.channelCount, interleaved: recordingFormat.isInterleaved) inputNode.installTap(onBus: 0, bufferSize: 1024, format: newFormat) { buffer, time in self.processAudioBuffer(buffer, time: time) } } else { inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { buffer, time in self.processAudioBuffer(buffer, time: time) } } do { audioEngine.prepare() try audioEngine.start() } catch { print(": \(error)") } } I back the app to the background and then call startAnalyzing(), which reports an error and the background recording permissions are configured。 error: [10429:570139] [aurioc] AURemoteIO.cpp:1668 AUIOClient_StartIO failed (561145187) [10429:570139] [avae] AVAEInternal.h:109 [AVAudioEngineGraph.mm:1545:Start: (err = PerformCommand(*ioNode, kAUStartIO, NULL, 0)): error 561145187 Audio engine couldn't start. Is background boot not allowed?
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515
Jan ’25
Playing audio live from Bluetooth headset on iPhone speaker
Hi guys, I am having issue in live-streaming audio from Bluetooth headset and playing it live on the iPhone speaker. I am able to redirect audio back to the headset but this is not what I want. The issue happens when I am trying to override output - the iPhone switches to speaker but also switches a microphone. This is example of the code: import AVFoundation class AudioRecorder { let player: AVAudioPlayerNode let engine:AVAudioEngine let audioSession:AVAudioSession let audioSessionOutput:AVAudioSession init() { self.player = AVAudioPlayerNode() self.engine = AVAudioEngine() self.audioSession = AVAudioSession.sharedInstance() self.audioSessionOutput = AVAudioSession() do { try self.audioSession.setCategory(AVAudioSession.Category.playAndRecord, options: [.defaultToSpeaker]) try self.audioSessionOutput.setCategory(AVAudioSession.Category.playAndRecord, options: [.allowBluetooth]) // enables Bluetooth HFP profile try self.audioSession.setMode(AVAudioSession.Mode.default) try self.audioSession.setActive(true) // try self.audioSession.overrideOutputAudioPort(.speaker) // doens't work } catch { print(error) } let input = self.engine.inputNode self.engine.attach(self.player) let bus = 0 let inputFormat = input.inputFormat(forBus: bus) self.engine.connect(self.player, to: engine.mainMixerNode, format: inputFormat) input.installTap(onBus: bus, bufferSize: 512, format: inputFormat) { (buffer, time) -> Void in self.player.scheduleBuffer(buffer) print(buffer) } } public func start() { try! self.engine.start() self.player.play() } public func stop() { self.player.stop() self.engine.stop() } } I am not sure if this is a bug or not. Can somebody point me into the right direction? I there a way to design a custom audio routing? I would also appreciate some good documentation besides AVFoundation docs.
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313
Mar ’25
NonLiDAR Photogrammetry
Hello! In iOS1.7.5, photogrammetry sessions cannot be performed on iPhones without LiDAR, but I don't think there is much difference in GPU performance between those with and without LiDAR. For example, the chips installed in the iPhone 14 Pro and iPhone 15 are the same A16 Bionic, and I think the GPU performance is also the same. Despite this, photogrammetry can be performed on the iPhone 14 Pro but not on the iPhone 15. Why is this? In fact, we have confirmed that if you transfer images taken with an iPhone 16 without LiDAR to an iPhone 16 Pro and run a photogrammetry session using those images, a 3D model can be generated. Also, will photogrammetry be able to be performed on high-performance iPhones without LiDAR in the future?
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80
Apr ’25
access transport in Logic Pro
hi, i need to read wether the transport is playing or stopped but my current method that works for vst does not work for au. is there a lpx resource available for developers anywhere? if (auto* playHead = processor->getPlayHead()) { juce::AudioPlayHead::CurrentPositionInfo posInfo; if (playHead->getCurrentPosition(posInfo)) { bool isCurrentlyPlaying = posInfo.isPlaying; if (isCurrentlyPlaying != wasTransportPlaying) { if (isCurrentlyPlaying) { wasTransportPlaying = isCurrentlyPlaying; startAllTimers(); } else { wasTransportPlaying = isCurrentlyPlaying; stopAllTimers(); } } } } thanks :)
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260
Mar ’25
Lightning to HDMI mirrors
I am developing a VOD playback app, but when I stream video to an external monitor connected via HDMI with Lightning on iOS 18 or later, the screen goes dark and I cannot confirm playback. The app I am developing does not detect the HDMI and display the Player separately, but simply mirrors the video. We have confirmed that the same phenomenon occurs with other services, but we were able to confirm playback with some services such as Apple TV. Please let us know if there are any other necessary settings such as video certificates required for video playback. We would also like to know if the problem occurs with iOS 18 or later.
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271
Mar ’25
Create live photo error
I want to create a Live Photo. The project includes a .jpg image and a .mov video (2 seconds). Two permissions in xcode have been added: Privacy - Photo Library Usage Description Privacy - Photo Library Additions Usage Description Simulate: iphone 16, ios 18.3 The codes in ContentView.swift : private func saveLivePhoto(imageURL: URL, videoURL: URL, completion: @escaping (Bool, Error?) -> Void) { PHPhotoLibrary.shared().performChanges { let creationRequest = PHAssetCreationRequest.forAsset() let options = PHAssetResourceCreationOptions() options.shouldMoveFile = false creationRequest.addResource(with: .photo, fileURL: imageURL, options: options) creationRequest.addResource(with: .pairedVideo, fileURL: videoURL, options: options) } completionHandler: { success, error in DispatchQueue.main.async { print(error) completion(success, error) } } } guard let imageURL = Bundle.main.url(forResource: "livephoto", withExtension: "jpeg"), let videoURL = Bundle.main.url(forResource: "livephoto", withExtension: "mov") else { showAlertMessage(title: "error", message: "cant find Live Photo ") return } print("imageURL: \(imageURL)") print("videoURL: \(videoURL)") saveLivePhoto(imageURL: imageURL, videoURL: videoURL) { success, error in if success { xxxxx } else { xxxxx } } Really need help, thanks
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194
Mar ’25
Above Xcode16 operation project, in the project use AVPictureInPictureController opportunities (PIP) function open system blackout
I found that when the development tool above Xcode16 ran my app, I opened the suspended inscription function, and then opened the system camera, the content in the suspended window would not be displayed, and the suspended window would have a black screen. However, this phenomenon does not appear on Xcode15.4 development tools, it is the same code, I do not know why
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657
Apr ’25
Processing AVCaptureVideoDataOutput video stream with appleLog and HLG_BT2020 AVCaptureColorSpace input
I’m building a professional camera app where users can customize the video recording format and color grading. In the func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) method, I handle video frames and use Metal for real-time color grading. This works well when device.activeColorSpace is sRGB or P3, and the results are great. However, when the color space is HLG_BT2020 or appleLog, the MTKTextureLoader.newTexture(cgImage: cgImage, options: options) method throws an error. After researching, I found that the video frame in these color spaces has a bit-per-channel (bpc) greater than 8 after being converted to CGImage, causing the texture creation to fail. I tried converting the CGImage to a lower bpc to successfully create the texture, but the final output image is garbled and not as expected. Is there a solution to this issue?
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123
Apr ’25
Help Needed: How to Make iOS Timer More Stable?
I’m currently developing an iOS metronome app using DispatchSourceTimer as the timer. The interval is set very small, around 50 milliseconds, and I’m using CFAbsoluteTimeGetCurrent to calculate the elapsed time to ensure the beat is played within a ±0.003-second margin. The problem is that once the app goes to the background, the timing becomes unstable—it slows down noticeably, then recovers after 1–2 seconds. When coming back to the foreground, it suddenly speeds up, and again, it takes 1–2 seconds to return to normal. It feels like the app is randomly “powering off” and then “overclocking.” It’s super frustrating. I’ve noticed that some metronome apps in the App Store have similar issues, but there’s one called “Professional Metronome” that’s rock solid with no such problems. What kind of magic are they using? Any experts out there who can help? Thanks in advance! P.S. I’ve already enabled background audio permissions. The professional metronome that has no issues: https://link.zhihu.com/?target=https%3A//apps.apple.com/cn/app/pro-metronome-%25E4%25B8%2593%25E4%25B8%259A%25E8%258A%2582%25E6%258B%258D%25E5%2599%25A8/id477960671
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555
Jan ’25
AVAudioSession automatically sets the tablet audio volume to 50% when recording audio.
Environment→ ・Device: iPad 10th generation ・OS:**iOS18.3.2 I'm using AVAudioSession to record sound in my application. But I recently came to realize that when the app starts a recording session on a tablet, OS automatically sets the tablet volume to 50% and when after recording ends, it doesn't change back to the previous volume level before starting the recording. So I would like to know whether this is an OS default behavior or a bug? If it's a default behavior, I much appreciate if I can get a link to the documentation.
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100
Apr ’25
Enabling MIDINetworkSession in a catalyst app
Hi, I am trying to enable the default MIDINetworkSession in a Catalyst app on MacOS like this: MIDINetworkSession.default().isEnabled = true MIDINetworkSession.default().connectionPolicy = .anyone In the AppSandbox I have both incoming and outgoing network connections enabled. And I also added the NSLocalNetworkUsageDescription key to the info.plist. Bonjour services are also added to the info.plist: NSBonjourServices _apple-midi._udp. Nevertheless the session stays disabled. Running the same code works just fine on iOS. Is there any special setup I need to make on MacOS to enable the MIDINetworkSession? Thanks!
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451
Dec ’24
AVPlayerItem. externalMetadata not available
According to the documentation (https://developer.apple.com/documentation/avfoundation/avplayeritem/externalmetadata), AVPlayerItem should have an externalMetadata property. However it does not appear to be visible to my app. When I try, I get: Value of type 'AVPlayerItem' has no member 'externalMetadata' Documentation states iOS 12.2+; I am building with a minimum deployment target of iOS 18. Code snippet: import Foundation import AVFoundation /// ... in function ... // create metadata as described in https://developer.apple.com/videos/play/wwdc2022/110338 var title = AVMutableMetadataItem() title.identifier = .commonIdentifierAlbumName title.value = "My Title" as NSString? title.extendedLanguageTag = "und" var playerItem = await AVPlayerItem(asset: composition) playerItem.externalMetadata = [ title ]
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73
Apr ’25
Unable to generate .p12 file from fairplay.cer
I am reaching out regarding an issue with my Apple FairPlay Streaming Certificate. To generate the certificate signing request (CSR), I used the following OpenSSL commands: openssl genrsa -out private_key.pem 1024 openssl req -new -key private_key.pem -out request.csr However, according to the guide provided by Apple and instructions from my DRM provider, I should have used: openssl genrsa -aes256 -out privatekey.pem 1024 openssl req -new -sha1 -key privatekey.pem -out certreq.csr -subj "/CN=SubjectName /OU=OrganizationalUnit /O=Organization /C=US" I suspect this discrepancy might be causing the issue with my FairPlay certificate. After obtaining the fairplay.cer file and importing it into Keychain Access, I noticed the following: When I expand the certificate in Keychain Access, I can only see a public key and no private key. As a result, I am unable to export the certificate as a .p12 file, as this option is disabled. As per my DRM provider's instructions, I need to export the certificate along with the corresponding private key as a .p12 file with a password. Since the private key is not visible in Keychain Access, I am unable to proceed further. I have read the FairPlay Streaming Overview but could not find any reasons as to why this issue is occurring or guidance on the procedure to revoke a certificate. Additionally, I came across the terms and conditions which mentioned reaching out to product-security at Apple for assistance in revoking corrupt certificates. However, despite reaching out, I have not received a response. Any help on how to proceed will be great!
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537
Jan ’25