Context
We develop an iOS/Apple TV app that allows to play HLS+FP Live streams (custom playback UI), some of which use the same FairPlay content key id. All FairPlay content keys are requested to the same content key server.
Implementation
Despite Apple documentation warning to not reuse AVContentKeySessions, we use only one AVContentKeySession for all channels which allows the system to reuse the content key when a content key id is met again. As seen in another thread, people seems to think this is OK.
Issue
When reusing the AVContentKeySession and the user quickly tunes channels multiple times (up to 2 or 3 times per second using gestures), an inconsistency may occur where the content key request for a previous streams is asked to the delegate after a new stream is already being prepared and its AVURLAsset already assigned as the content key session AVContentKeyRecipient. Note that the previous content key recipient is removed before the new one is added.
We also have been reported for crashes (though I haven't experienced it myself) when performing multiple channels tunings which makes us think that the AVContentKeySession should definitely not been reused.
Note: On the other hand if a new AVContentKeySession is used for each stream, the system systematically requests a content key even if previous streams have used the same content key id. In this case, neither the crash nor the inconsistency issue are observed but it dramatically increases the number of calls to the content key server.
Questions
Should AVContentKeySessions definitely not be reused? Otherwise, how to handle the inconsistency issue described above?
AVFoundation
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Hi,
Currently I am developing a 3D reconstruction project.
Which requires images to be distortion-free (rectilinear) and with known intrinsics.
The session I am developing on is a builtInDualWideCamera, with isGeometricDistortionCorrectionEnabled set to false to be able to get the intrinsic matrix of the images, isVirtualDeviceConstituentPhotoDeliveryEnabled set to true and isAutoVirtualDeviceFusionEnabled set to false to get both images and isCameraCalibrationDataDeliveryEnabled set to true to actually get the calibration data.
The distortion correction parameters such as lensDistortionLookupTable are used.
The 42 coefficients mapping array is used as described in the AVCameraCalibrationData header file. A simple piecewise linear interpolation.
There are two questions I would like to get support on:
A way to set the calibration parameters in each image.
I have an approach that sets the parameters in the kCGImagePropertyExifDictionary -> "UserComment". Is there a better approach to write calibration parameter data into the images? I feel like this is a bit dirty and there might be a better and neat approach.
For the ultra-wide angle camera's images, the lensDistortionLookupTable contains several zeros at the end of the array.
For example (last 10 elements are zero):
"LensDistortionLookupTable":"0.000000000000000,0.000349554029526,0.001385628827848,0.003071037586778,... ,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000"
The problem comes when the complete array is used to correct the image (including zeros), the end result is a wrapped-like-circle image close to the edges of it which is completely wrong.
In contrast, if the LensDistortionLookupTable is used without the last zeros and the new size accommodated the image looks better (although not as rectilinear as if you take the image from the iPhone's camera app), but definitely less distorted.
Including zeros (full array):
Excluding zeros (array size changed):
Am I missing an important point in the usage of the lensDistortionLookupTable where this case is addressed (zeros at the end)?
What is the criteria to shrink/exclude elements of the array?
Any advice is very much welcome.
I am attempting to use the AVSpeechSynthesizer to include text to speech in my Swift Playgrounds project, but when I attempt to use it on my IPhone i get the following errors:
It works just fine on the simulator, but no audio is produced when I run it on-device. Is there a way to set this "bundle display name" within Swift Playgrounds, or are there any workarounds?
My code:
import AVFoundation
class Speaker {
let synthesizer = AVSpeechSynthesizer()
func speak() {
let utterance = AVSpeechUtterance(string: "Test, I am the speaker")
synthesizer.speak(utterance)
}
}
I’m working on a macOS app, written in Swift. My goal is to record audio from an external microphone, e.g., one connected via USB.
For this, I’m using an AVCaptureSession and recording its output with an AVAssetWriter. This works perfectly in principle (and reliably with internal microphones, for example).
The problem occurs after my app has successfully completed the first recording and I then want to make additional recordings (which makes me think it might be process-dependent, because it works again after restarting the app).
The problem: Noisy or distorted-sounding audio files. In addition, the following error message appears in the Console from CoreAudio / its AudioConverter:
Input data proc returned inconsistent 512 packets for 2048 bytes; at 3 bytes per packet, that is actually 682 packets
It is easy to reproduce. This problem is reproducible even if I don’t configure the AVAssetWriter manually and instead let it receive its audioSettings using a preset from an AVOutputSettingsAssistant. I’m running on macOS 15.0 (24A335).
I’ve filed a feedback including a demo project → FB15333298 🎟️
I would greatly appreciate any help!
Have a great day,
Martin
Hello,
Our users have started to see a new fatal AVPlayer error during playback starting with iOS/tvOS 18.0. The error is defined as "CoreMediaErrorDomain Code=-15486".
We have not been able to reproduce this issue locally within our development team.
Is there any documentation on the cause of this error or steps to recover from this error?
Thank you,
Howard
Topic:
Media Technologies
SubTopic:
Streaming
Tags:
FairPlay Streaming
HTTP Live Streaming
AVFoundation
When I was working on my project for Swift Student Challenge, I found an interesting fact regarding camera access. If I create an App project on Xcode, the camera capture works well on it. However, if I copied and pasted the code on an App Playground project on Xcode, it crashed and output several errors. I am wondering why this is happening.
Topic:
Community
SubTopic:
Swift Student Challenge
Tags:
Swift Playground
SwiftUI
Camera
AVFoundation
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
I am would like to look at AVMetricEvent data during video playback, so I have added this code to a test video player app:
let playerItem: AVPlayerItem = ...
let allMetrics = playerItem.allMetrics()
Task.init {
print("metrics task started")
do {
for try await metricEvent in allMetrics {
print("metric event: \(metricEvent.description)")
}
} catch {
print("unexpected metric iterator error \(error)")
}
}
Running this in Simulator on iPhone 16 Pro (18.0) does not result in any "metric event" diagnostic messages being printed when the video associated with this AVPlayerItem is playing. Only the "metric task started" diagnostic message is seen.
What am I doing wrong that prevents metric data being received?
I have an HDR10+ encoded video that if loaded as a mov plays back on the Apple Vision Pro but when that video is encoded using the latest (1.23b) Apple HLS tools to generate an fMP4 - the resulting m3u8 cannot be played back in the Apple Vision Pro and I only get back a "Cannot Open" error.
To generate the m3u8, I'm just calling mediafilesegmenter (with -iso-fragmented) and then variantplaylistcreator. This completes with no errors but the m3u8 will playback on the Mac using VLC but not on the Apple Vision Pro.
The relevant part of the m3u8 is:
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=40022507,BANDWIDTH=48883974,VIDEO-RANGE=PQ,CODECS="ec-3,hvc1.1.60000000.L180.B0",RESOLUTION=4096x4096,FRAME-RATE=24.000,CLOSED-CAPTIONS=NONE,AUDIO="audio1",REQ-VIDEO-LAYOUT="CH-STEREO"
{{url}}
Has anyone been able to use the HLS tools to generate fMP4s of MV-HEVC videos with HDR10?
Hi,
just generated a HDR10 MVHEVC file, mediainfo is below:
Color range : Limited
Color primaries : BT.2020
Transfer characteristics : PQ
Matrix coefficients : BT.2020 non-constant
Codec configuration box : hvcC+lhvC
then generate the segment files with below command:
mediafilesegmenter --iso-fragmented -t 4 -f av_1 av_new_1.mov
then upload the segment files and prog_index.m3u8 to web server.
just find that can not play the HLS stream on Safari...
the url is http://ip/vod/prog_index.m3u8
just checked that if i remove the tag Transfer characteristics : PQ when generating the MVHEVC file.
above same mediafilesegmenter command and upload the files to web server.
the new version of HLS stream is can play on Safari...
Is there any way to play HLS PQ video on Safari. thanks.
Hello,
I have a CarPlay Navigation app and utilize the AVSpeechSynthesizer to speak directions to a user. Everything works great on my CarPlay simulator as well as when plugged into my GMC truck. However, I found out yesterday that one of my users with a Ford truck the audio would cut in an out.
After much troubleshooting, I was able to replicate this on my own truck when using Bluetooth to connect to CarPlay. My user was also utilizing Bluetooth. Has anyone else experienced this? Is there a fix to the problem?
import SwiftUI
import AVFoundation
class TextToSpeechService: NSObject, ObservableObject, AVSpeechSynthesizerDelegate {
private var speechSynthesizer = AVSpeechSynthesizer()
static let shared = TextToSpeechService()
override init() {
super.init()
speechSynthesizer.delegate = self
}
func configureAudioSession() {
speechSynthesizer.delegate = self
do {
try AVAudioSession.sharedInstance().setCategory(.playback, mode: .voicePrompt, options: [.mixWithOthers, .allowBluetooth])
} catch {
print("Failed to set audio session category: \(error.localizedDescription)")
}
}
func speak(_ text: String) {
Task(priority: .high) {
let speechUtterance = AVSpeechUtterance(string: text)
speechUtterance.voice = AVSpeechSynthesisVoice(language: AVSpeechSynthesisVoice.currentLanguageCode())
try AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation)
speechSynthesizer.speak(speechUtterance)
}
}
func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didFinish utterance: AVSpeechUtterance) {
Task {
stopSpeech()
try AVAudioSession.sharedInstance().setActive(false)
}
}
func stopSpeech() {
speechSynthesizer.stopSpeaking(at: .immediate)
}
}
I am facing an issue in iOS 18 that works fine in iOS 17 and earlier.
This happens when you set the project to use Swift 6, if you set swift 5 this will work ok.
The app has the Privacy - Camera Usage Description key in the Info.plist.
It is a wrapper that implements UIViewControllerRepresentable to create the UIViewController. This wrapper is within a view that gets pushed when the user presses a button (see snippet code below).
Sometimes, I get a popup asking for permission to access the camera, and the app crashes immediately. Other times, I don’t see the popup, and the app crashes right away.
I tried adding Task { @MainActor } within the requestAccess closure, but it did not resolve the issue. It does not matter the code within the closure; it crashes even if the closure is empty.
The crash trace shows _dispatch_assert_queue_fail (see the attached image).
Has anyone else experienced this issue? Any insights would be greatly appreciated.
The following code will crash if run as is.
***** Please add the Privacy - Camera Usage Description key in the Info.plist to prevent this issue.
import SwiftUI
import AVFoundation
struct ContentView: View {
var body: some View {
VStack {
Text("Hello, world!")
ViewControllerWrapper()
}
}
}
struct ViewControllerWrapper: UIViewControllerRepresentable {
func makeUIViewController(context: Context) -> ViewController {
ViewController()
}
func updateUIViewController(_ viewController: ViewController, context: Context) {}
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
AVCaptureDevice.requestAccess(for: .video) { _ in
}
}
}
Hi All,
I am working on a DJ playout app (MACOS). The app has a few AVAudioPlayerNode's combined with the ApplicationMusicPlayer from Musickit. I can route the output of the AVaudioPlayer to a hardware device so that the audio files are directed to their own dedicated output on my Mac. The ApplicationMusicPlayer is following the default output and this is pretty annoying.
Has anyone found a solution to chain the ApplicationMusicPlayer and get it set to a output device?
Thanks
Pancras
I’m currently working on a project where I capture both depth frames and RGB frames using AVCaptureDataOutputSynchronizer. Depth frames are stored as raw binary data and RGB frames are saved with AVAssetWriter.
The issue I’m facing is that AVAssetWriter enforces a fixed framerate, meaning it adds or discards frames to maintain that rate (as I understand it). This causes a desynchronization between the depth and RGB frames, which is a problem because I need each depth frame to be exactly matched with the corresponding RGB frame as they were captured.
How can I ensure that the RGB frames are saved without AVAssetWriter modifying the frame count?
}
// Start listening to the microphone
public void StartListening()
{
if (!isListening)
{
#if UNITY_IOS || UNITY_TVOS
microphoneInput = Microphone.Start(null, true, 10, 44100);
#else
try
{
microphoneInput = Microphone.Start(null, true, 10, 16000); // Use 16,000 Hz instead of 44,100
if (microphoneInput == null)
{
microphoneInput = Microphone.Start(null, true, 10, AudioSettings.outputSampleRate);
}
#endif
isListening = true;
Debug.Log(Microphone.devices.Length + " Started listening...");
debugText.text = Microphone.devices.Length + "- Started listening...";
}
catch (System.Exception e)
{
Debug.LogError($"Starting microphone failed: {e.Message}");
debugText.text = $"Starting microphone failed: {e.Message}";
}
}
}
void Update()
{
if (isListening && microphoneInput != null)
{
// Analyze the audio for voice activity
float volume = GetAverageVolume();
if (volume > detectionThreshold)
{
Debug.Log("User is speaking!");
lastVoiceTime = Time.time;
SoundDetected = true;
if (Time.time - lastVoiceTime > silenceDuration)
{
Debug.Log("User is silent.");
debugText.text = volume.ToString() + " - User is silent.";
}
slider.value = volume;
}
}
}
private float GetAverageVolume()
{
float[] samples = new float[128];
microphoneInput.GetData(samples, Microphone.GetPosition(null));
float sum = 0f;
foreach (float sample in samples)
{
sum += Mathf.Abs(sample);
}
return sum / samples.Length;
}
Problem:
When I build and run the app from Xcode, the microphone works fine, and I receive input. However, when running the app normally (outside of Xcode), I can’t seem to access the microphone. The debug logs indicate no microphone is detected.
Question:
Is there any additional configuration I need to do for the microphone to work in a normal (non-Xcode) run on Vision Pro? Or any common issues that could be causing the microphone access to fail in this scenario?
Thanks in advance for any insights!
Best,
Siddharth
Getting this error in iPhone Portrait Mode with notch.
Currrently using AVQueuePlayer to play more than 30 mp3 files one by one.
All constraint properties are correct but error occures only in Apple iPhone Portrait Mode with notch series. But same code works on same iPhone in Landscape mode.
**But I get this error: **
LoudnessManager.mm:709 unable to open stream for LoudnessManager plist
Type: Error | Timestamp: 2025-02-07 | Process: | Library: AudioToolbox | Subsystem: com.apple.coreaudio | Category: aqme | TID: 0x42754
LoudnessManager.mm:709 unable to open stream for LoudnessManager plist
LoudnessManager.mm:709 unable to open stream for LoudnessManager plist
Timestamp: 2025-02-07 | Library: AudioToolbox | Subsystem: com.apple.coreaudio | Category: aqme
For some users in production, there's a high probability that after launching the App, using AVPlayer to play any local audio resources results in the following error. Restarting the App doesn't help.
issue:
[error: Error Domain=AVFoundationErrorDomain Code=-11800 "这项操作无法完成" UserInfo={NSLocalizedFailureReason=发生未知错误(24), NSLocalizedDescription=这项操作无法完成, NSUnderlyingError=0x30311f270 {Error Domain=NSPOSIXErrorDomain Code=24 "Too many open files"}}
I've checked the code, and there aren't actually multiple AVPlayers playing simultaneously. What could be causing this?
I’m facing a problem while trying to achieve spatial audio effects in my iOS 18 app. I have tried several approaches to get good 3D audio, but the effect never felt good enough or it didn’t work at all.
Also what mostly troubles me is I noticed that AirPods I have doesn’t recognize my app as one having spatial audio (in audio settings it shows "Spatial Audio Not Playing"). So i guess my app doesn't use spatial audio potential.
First approach uses AVAudioEnviromentNode with AVAudioEngine. Chaining position of player as well as changing listener’s doesn’t seem to change anything in how audio plays.
Here's simple how i initialize AVAudioEngine
import Foundation
import AVFoundation
class AudioManager: ObservableObject {
// important class variables
var audioEngine: AVAudioEngine!
var environmentNode: AVAudioEnvironmentNode!
var playerNode: AVAudioPlayerNode!
var audioFile: AVAudioFile?
...
//Sound set up
func setupAudio() {
do {
let session = AVAudioSession.sharedInstance()
try session.setCategory(.playback, mode: .default, options: [])
try session.setActive(true)
} catch {
print("Failed to configure AVAudioSession: \(error.localizedDescription)")
}
audioEngine = AVAudioEngine()
environmentNode = AVAudioEnvironmentNode()
playerNode = AVAudioPlayerNode()
audioEngine.attach(environmentNode)
audioEngine.attach(playerNode)
audioEngine.connect(playerNode, to: environmentNode, format: nil)
audioEngine.connect(environmentNode, to: audioEngine.mainMixerNode, format: nil)
environmentNode.listenerPosition = AVAudio3DPoint(x: 0, y: 0, z: 0)
environmentNode.listenerAngularOrientation = AVAudio3DAngularOrientation(yaw: 0, pitch: 0, roll: 0)
environmentNode.distanceAttenuationParameters.referenceDistance = 1.0 environmentNode.distanceAttenuationParameters.maximumDistance = 100.0
environmentNode.distanceAttenuationParameters.rolloffFactor = 2.0
// example.mp3 is mono sound
guard let audioURL = Bundle.main.url(forResource: "example", withExtension: "mp3") else {
print("Audio file not found")
return
}
do {
audioFile = try AVAudioFile(forReading: audioURL)
} catch {
print("Failed to load audio file: \(error)")
}
}
...
//Playing sound
func playSpatialAudio(pan: Float ) {
guard let audioFile = audioFile else { return }
// left side
playerNode.position = AVAudio3DPoint(x: pan, y: 0, z: 0)
playerNode.scheduleFile(audioFile, at: nil, completionHandler: nil)
do {
try audioEngine.start()
playerNode.play()
} catch {
print("Failed to start audio engine: \(error)")
}
...
}
Second more complex approach using PHASE did better. I’ve made an exemplary app that allows players to move audio player in 3D space. I have added reverb, and sliders changing audio position up to 10 meters each direction from listener but audio seems to only really change left to right (x axis) - again I think it might be trouble with the app not being recognized as spatial.
//Crucial class Variables:
class PHASEAudioController: ObservableObject{
private var soundSourcePosition: simd_float4x4 = matrix_identity_float4x4
private var audioAsset: PHASESoundAsset!
private let phaseEngine: PHASEEngine
private let params = PHASEMixerParameters()
private var soundSource: PHASESource
private var phaseListener: PHASEListener!
private var soundEventAsset: PHASESoundEventNodeAsset?
// Initialization of PHASE
init{
do {
let session = AVAudioSession.sharedInstance()
try session.setCategory(.playback, mode: .default, options: [])
try session.setActive(true)
} catch {
print("Failed to configure AVAudioSession: \(error.localizedDescription)")
}
// Init PHASE Engine
phaseEngine = PHASEEngine(updateMode: .automatic)
phaseEngine.defaultReverbPreset = .mediumHall
phaseEngine.outputSpatializationMode = .automatic //nothing helps
// Set listener position to (0,0,0) in World space
let origin: simd_float4x4 = matrix_identity_float4x4
phaseListener = PHASEListener(engine: phaseEngine)
phaseListener.transform = origin
phaseListener.automaticHeadTrackingFlags = .orientation
try! self.phaseEngine.rootObject.addChild(self.phaseListener)
do{
try self.phaseEngine.start();
}
catch {
print("Could not start PHASE engine")
}
audioAsset = loadAudioAsset()
// Create sound Source
// Sphere
soundSourcePosition.translate(z:3.0)
let sphere = MDLMesh.newEllipsoid(withRadii: vector_float3(0.1,0.1,0.1), radialSegments: 14, verticalSegments: 14, geometryType: MDLGeometryType.triangles, inwardNormals: false, hemisphere: false, allocator: nil)
let shape = PHASEShape(engine: phaseEngine, mesh: sphere)
soundSource = PHASESource(engine: phaseEngine, shapes: [shape])
soundSource.transform = soundSourcePosition
print(soundSourcePosition)
do {
try phaseEngine.rootObject.addChild(soundSource)
}
catch {
print ("Failed to add a child object to the scene.")
}
let simpleModel = PHASEGeometricSpreadingDistanceModelParameters()
simpleModel.rolloffFactor = rolloffFactor
soundPipeline.distanceModelParameters = simpleModel
let samplerNode = PHASESamplerNodeDefinition(
soundAssetIdentifier: audioAsset.identifier,
mixerDefinition: soundPipeline,
identifier: audioAsset.identifier + "_SamplerNode")
samplerNode.playbackMode = .looping
do {soundEventAsset = try
phaseEngine.assetRegistry.registerSoundEventAsset(
rootNode: samplerNode,
identifier: audioAsset.identifier + "_SoundEventAsset")
} catch {
print("Failed to register a sound event asset.")
soundEventAsset = nil
}
}
//Playing sound
func playSound(){
// Fire new sound event with currently set properties
guard let soundEventAsset else { return }
params.addSpatialMixerParameters(
identifier: soundPipeline.identifier,
source: soundSource,
listener: phaseListener)
let soundEvent = try! PHASESoundEvent(engine: phaseEngine,
assetIdentifier: soundEventAsset.identifier,
mixerParameters: params)
soundEvent.start(completion: nil)
}
...
}
Also worth mentioning might be that I only own personal team account
I’ve tried both AVCaptureVideoDataOutputSampleBufferDelegate (captureOutput) and AVCaptureDataOutputSynchronizerDelegate (dataOutputSynchronizer), but the number of depth frames and saved timestamps is significantly lower than the number of frames in the .mp4 file written by AVAssetWriter.
In my code, I save:
Timestamps for each frame to a metadata file
Depth frames to a binary file
Video to an .mp4 file
If I record a 4-second video at 30fps, the .mp4 file correctly plays for 4 seconds, but the number of stored timestamps and depth frames is much lower—around 70 frames instead of the expected 120.
Does anyone know why this mismatch happens?
func dataOutputSynchronizer(_ synchronizer: AVCaptureDataOutputSynchronizer,
didOutput synchronizedDataCollection: AVCaptureSynchronizedDataCollection) {
// Read all outputs
guard let syncedDepthData: AVCaptureSynchronizedDepthData =
synchronizedDataCollection.synchronizedData(for: depthDataOutput) as? AVCaptureSynchronizedDepthData,
let syncedVideoData: AVCaptureSynchronizedSampleBufferData =
synchronizedDataCollection.synchronizedData(for: videoDataOutput) as? AVCaptureSynchronizedSampleBufferData else {
// only work on synced pairs
return
}
if syncedDepthData.depthDataWasDropped || syncedVideoData.sampleBufferWasDropped {
return
}
let depthData = syncedDepthData.depthData
let depthPixelBuffer = depthData.depthDataMap
let sampleBuffer = syncedVideoData.sampleBuffer
guard let videoPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer),
let formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer) else {
return
}
addToPreviewStream?(CIImage(cvPixelBuffer: videoPixelBuffer))
if !canWrite() {
return
}
// Extract the presentation timestamp (PTS) from the sample buffer
let timestamp = CMSampleBufferGetPresentationTimeStamp(sampleBuffer)
//sessionAtSourceTime is the first buffer we will write to the file
if self.sessionAtSourceTime == nil {
//Make sure we don't start recording until the buffer reaches the correct time (buffer is always behind, this will fix the difference in time)
guard sampleBuffer.presentationTimeStamp >= self.recordFromTime! else { return }
self.sessionAtSourceTime = sampleBuffer.presentationTimeStamp
self.videoWriter!.startSession(atSourceTime: sampleBuffer.presentationTimeStamp)
}
if self.videoWriterInput!.isReadyForMoreMediaData {
self.videoWriterInput!.append(sampleBuffer)
self.videoTimestamps.append(
Timestamp(
frame: videoTimestamps.count,
value: timestamp.value,
timescale: timestamp.timescale
)
)
let ddm = depthData.depthDataMap
depthCapture.addDepthData(pixelBuffer: ddm, timestamp: timestamp)
}
}
I am trying to use AVCaptureDevice.rotationCoordinator API to observe angles for preview and capture and it seems there is an issue with the API when used with arbitrary CALayer (which is not a AVCaptureVideoPreviewLayer) and switching cameras.
Here is my setup. The below function is defined in an actor class called CameraManager that performs setup of rotationCoordinator.
func updateRotationCoordinator(_ callback:@escaping @MainActor (CGFloat) -> Void) {
guard let device = sessionConfiguration.activeVideoInput?.device, let displayLayer = displayLayer else { return }
cancellables.removeAll()
rotationCoordinator = AVCaptureDevice.RotationCoordinator(device: device, previewLayer: displayLayer)
guard let coordinator = rotationCoordinator else { return }
coordinator.publisher(for: \.videoRotationAngleForHorizonLevelPreview)
.receive(on: DispatchQueue.main)
.sink { degrees in
let radians = degrees * .pi / 180
MainActor.assumeIsolated {
callback(radians)
}
}
.store(in: &cancellables)
}
This works the very first time but when I switch cameras and call this function again, it throws a runtime error that view's layer is modified from a non-main thread. This happens at the very line where rotation coordinator is been recreated. It's not clear why initialising rotation coordinator should modify CALayer properties right in it's init method.
Modifying properties of a view's layer off the main thread is not allowed: view <MyApp.DisplayLayerView: 0x102ffaf40> with nearest ancestor view controller <_TtGC7SwiftUI19UIHostingControllerGVS_15ModifiedContentVS_7AnyViewVS_12RootModifier__: 0x101f7fb80>; backtrace:
(
0 UIKitCore 0x0000000194a977b4 575E5140-FA6A-37C2-B00B-A4EACEDFDA53 + 22509492
1 UIKitCore 0x000000019358594c 575E5140-FA6A-37C2-B00B-A4EACEDFDA53 + 416076
2 QuartzCore 0x00000001927f5bd8 D8E8E86D-85AC-3C90-B2E1-940235ECAA18 + 43992
3 QuartzCore 0x00000001927f5a4c D8E8E86D-85AC-3C90-B2E1-940235ECAA18 + 43596
4 QuartzCore 0x000000019283a41c D8E8E86D-85AC-3C90-B2E1-940235ECAA18 + 324636
5 QuartzCore 0x000000019283a0a8 D8E8E86D-85AC-3C90-B2E1-940235ECAA18 + 323752
6 AVFCapture 0x00000001af072a18 09192166-E0B6-346C-B1C2-7C95C3EFF7F7 + 420376
7 MyApp.debug.dylib 0x0000000105fa3914 $s10MyApp15CapturePipelineC25updateRotationCoordinatoryyy12CoreGraphics7CGFloatVScMYccF + 972
8 MyApp.debug.dylib 0x00000001063ade40 $s10MyApp11CameraModelC18switchVideoDevicesyyYaFTY3_ + 72
9 MyApp.debug.dylib 0x0000000105fe3cbd $s10MyApp11ContentViewV4bodyQrvg7SwiftUI6VStackVyAE05TupleE0VyAE6HStackVyAIyAE6SpacerV_AE6ButtonVyAE0E0PAEE5frame5width6height9alignmentQr12CoreGraphics7CGFloatVSg_AyE9AlignmentVtFQOyAqEE11scaledToFitQryFQOyAqEE10imageScaleyQrAE5ImageV0Z0OFQOyA3__Qo__Qo__Qo_GtGG_AmKyAIyAKyAIyAqEE7paddingyQrAE4EdgeO3SetV_AYtFQOyAA07CaptureM0V_Qo__AOyAE4TextVGAmKyAIyA9__AqEEArstUQrAY_AYA_tFQOyAM_Qo_A9_tGGtGG_AmqEE10background_AUQrqd___A_tAePRd__lFQOyAqEEArstUQrAY_AYA_tFQOyA21__Qo__AqEEArstUQrAY_AYA_tFQOyAE06_ShapeE0VyAE9RectangleVAE5ColorVG_Qo_Qo_SgtGGtGGyXEfU0_A42_yXEfU_A10_yXEfU_yyScMYccfU_yyYacfU_TQ1_ + 1
10 MyApp.debug.dylib 0x0000000105ff06d9 $s10MyApp11ContentViewV4bodyQrvg7SwiftUI6VStackVyAE05TupleE0VyAE6HStackVyAIyAE6SpacerV_AE6ButtonVyAE0E0PAEE5frame5width6height9alignmentQr12CoreGraphics7CGFloatVSg_AyE9AlignmentVtFQOyAqEE11scaledToFitQryFQOyAqEE10imageScaleyQrAE5ImageV0Z0OFQOyA3__Qo__Qo__Qo_GtGG_AmKyAIyAKyAIyAqEE7paddingyQrAE4EdgeO3SetV_AYtFQOyAA07CaptureM0V_Qo__AOyAE4TextVGAmKyAIyA9__AqEEArstUQrAY_AYA_tFQOyAM_Qo_A9_tGGtGG_AmqEE10background_AUQrqd___A_tAePRd__lFQOyAqEEArstUQrAY_AYA_tFQOyA21__Qo__AqEEArstUQrAY_AYA_tFQOyAE06_ShapeE0VyAE9RectangleVAE5ColorVG_Qo_Qo_SgtGGtGGyXEfU0_A42_yXEfU_A10_yXEfU_yyScMYccfU_yyYacfU_TATQ0_ + 1
11 MyApp.debug.dylib 0x0000000105f9c595 $sxIeAgHr_xs5Error_pIegHrzo_s8SendableRzs5NeverORs_r0_lTRTQ0_ + 1
12 MyApp.debug.dylib 0x0000000105f9fb3d $sxIeAgHr_xs5Error_pIegHrzo_s8SendableRzs5NeverORs_r0_lTRTATQ0_ + 1
13 libswift_Concurrency.dylib 0x000000019c49fe39 E15CC6EE-9354-3CE5-AF91-F641CA8283E0 + 433721
)