quotes are displayed incorrectly in subtitles of AVPlayerViewController when streaming VOD content using HLS.
single quote ' (escaped ') is displayed as apos;
double quotes " (escaped ") is displayed as quot;
following the vtt specification.
The same stream works fine in VLC player, showing quotes correctly in subtitles.
subtitle vtt files use
Content-Type: text/vtt
WEBVTT
X-TIMESTAMP-MAP=LOCAL:490014:06:04.000,MPEGTS:158764568760056
example line:
490014:05:46.000 --> 490014:05:50.440 align:start line:83% position:14%
and the playlist has:
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",LANGUAGE="da",NAME="Dansk",AUTOSELECT=YES,CHARACTERISTICS="public.accessibility.transcribes-spoken-dialog,public.accessibility.describes-music-and-sound",URI="subs/dan_5/playlist.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=780000,CODECS="mp4a.40.5,avc1.42c01e",RESOLUTION=256x144,AUDIO="audio-aac",SUBTITLES="subs"
lære dig endnu bedre at kende."
adding 'wvtt' to CODECS list in playlist does not make a difference.
Is this a known bug? Is there a workaround?
I guess the AVResourceLoaderDelegate can be used to intercept and parse the subtitle files, but it seems like quite a hack and not really intended to be used for this.
Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.
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Hello,
I'm investigating an issue with LL-HLS playback using AVPlayer, specifically during DVR Live seeking (seeking to a past time).
I noticed that in certain seeking scenarios, AVPlayer sends a Blocking Playlist Reload request that includes the _HLS_msn parameter but is missing the _HLS_part parameter.
While I understand this is compliant with the HLS spec, I would like to know the specific criteria AVPlayer uses to decide when to drop the _HLS_part parameter. Does AVPlayer intentionally omit the part info when it determines that loading a specific partial segment is unnecessary during a seek operation?
Clarification on this behavior would help us greatly in debugging our stream delivery.
Thanks in advance.
Hi folks - I'm having trouble finding specific documentation about Audio Unit MIDI plugins - as in MIDI -only. Any suggestions welcome as searches aren't returning much. (too niche? user error?)
Topic:
Media Technologies
SubTopic:
Audio
Hello, I requested Fairplay credentials a week ago. Where can I check the status of my request? Thank you very much.
The team ID is: 6WZ8SVRYV9
A functioning Multiplatform app, which includes use of Continuity Camera on an M1MacMini running Sequoia 15.5, works correctly capturing photos with AVCapturePhoto. However, that app (and a test app just for Continuity Camera) crashes at delegate callback when run on a 2017 MacBookPro under MacOS 13.7.5. The app was created with Xcode 16 (various releases) and using Swift 6 (but tried with 5). Compiling and running the test app with Xcode 15.2 on the 13.7.5 machine also crashes at delegate callback.
The iPhone 15 Continuity Camera gets detected and set up correctly, and preview video works correctly. It's when the CapturePhoto code is run that the crash occurs.
The relevant capture code is:
func capturePhoto() {
let captureSettings = AVCapturePhotoSettings()
captureSettings.flashMode = .auto
photoOutput.maxPhotoQualityPrioritization = .quality
photoOutput.capturePhoto(with: captureSettings, delegate: PhotoDelegate.shared)
print("**** CameraManager: capturePhoto")
}
and the delegate callbacks are:
class PhotoDelegate: NSObject, AVCapturePhotoCaptureDelegate {
nonisolated(unsafe) static let shared = PhotoDelegate()
// MARK: - Delegate callbacks
func photoOutput(
_ output: AVCapturePhotoOutput,
didFinishProcessingPhoto photo: AVCapturePhoto,
error: (any Error)?
) {
print("**** CameraManager: didFinishProcessingPhoto")
guard let pData = photo.fileDataRepresentation() else {
print("**** photoOutput is empty")
return
}
print("**** photoOutput data is \(pData.count) bytes")
}
func photoOutput(
_ output: AVCapturePhotoOutput,
willBeginCaptureFor resolvedSettings: AVCaptureResolvedPhotoSettings
) {
print("**** CameraManager: willBeginCaptureFor")
}
func photoOutput(_ output: AVCapturePhotoOutput, willCapturePhotoFor resolvedSettings: AVCaptureResolvedPhotoSettings) {
print("**** CameraManager: willCaptureCapturePhotoFor")
}
}
The crash report significant parts are.....
Crashed Thread: 3 Dispatch queue: com.apple.cmio.CMIOExtensionProviderHostContext
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000000
Exception Codes: 0x0000000000000001, 0x0000000000000000
Termination Reason: Namespace SIGNAL, Code 11 Segmentation fault: 11
Terminating Process: exc handler [30850]
VM Region Info: 0 is not in any region. Bytes before following region: 4296495104
REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL
UNUSED SPACE AT START
--->
__TEXT 100175000-10017f000 [ 40K] r-x/r-x SM=COW ...tinuityCamera
Thread 0:: Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x7ff803aed552 mach_msg2_trap + 10
1 libsystem_kernel.dylib 0x7ff803afb6cd mach_msg2_internal + 78
2 libsystem_kernel.dylib 0x7ff803af4584 mach_msg_overwrite + 692
3 libsystem_kernel.dylib 0x7ff803aed83a mach_msg + 19
4 CoreFoundation 0x7ff803c07f8f __CFRunLoopServiceMachPort + 145
5 CoreFoundation 0x7ff803c06a10 __CFRunLoopRun + 1365
6 CoreFoundation 0x7ff803c05e51 CFRunLoopRunSpecific + 560
7 HIToolbox 0x7ff80d694f3d RunCurrentEventLoopInMode + 292
8 HIToolbox 0x7ff80d694d4e ReceiveNextEventCommon + 657
9 HIToolbox 0x7ff80d694aa8 _BlockUntilNextEventMatchingListInModeWithFilter + 64
10 AppKit 0x7ff806ca59d8 _DPSNextEvent + 858
11 AppKit 0x7ff806ca4882 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 1214
12 AppKit 0x7ff806c96ef7 -[NSApplication run] + 586
13 AppKit 0x7ff806c6b111 NSApplicationMain + 817
14 SwiftUI 0x7ff90e03a9fb 0x7ff90dfb4000 + 551419
15 SwiftUI 0x7ff90f0778b4 0x7ff90dfb4000 + 17578164
16 SwiftUI 0x7ff90e9906cf 0x7ff90dfb4000 + 10340047
17 ContinuityCamera 0x10017b49e 0x100175000 + 25758
18 dyld 0x7ff8037d1418 start + 1896
Thread 1:
0 libsystem_pthread.dylib 0x7ff803b27bb0 start_wqthread + 0
Thread 2:
0 libsystem_pthread.dylib 0x7ff803b27bb0 start_wqthread + 0
Thread 3 Crashed:: Dispatch queue: com.apple.cmio.CMIOExtensionProviderHostContext
0 ??? 0x0 ???
1 AVFCapture 0x7ff82045996c StreamAsyncStillCaptureCallback + 61
2 CoreMediaIO 0x7ff813a4358f __94-[CMIOExtensionProviderHostContext captureAsyncStillImageWithStreamID:uniqueID:options:reply:]_block_invoke + 498
3 libxpc.dylib 0x7ff803875b33 _xpc_connection_reply_callout + 36
4 libxpc.dylib 0x7ff803875ab2 _xpc_connection_call_reply_async + 69
5 libdispatch.dylib 0x7ff80398b099 _dispatch_client_callout3 + 8
6 libdispatch.dylib 0x7ff8039a6795 _dispatch_mach_msg_async_reply_invoke + 387
7 libdispatch.dylib 0x7ff803991088 _dispatch_lane_serial_drain + 393
8 libdispatch.dylib 0x7ff803991d6c _dispatch_lane_invoke + 417
9 libdispatch.dylib 0x7ff80399c3fc _dispatch_workloop_worker_thread + 765
10 libsystem_pthread.dylib 0x7ff803b28c55 _pthread_wqthread + 327
11 libsystem_pthread.dylib 0x7ff803b27bbf start_wqthread + 15
Of course, the MacBookPro is an old device - but Continuity Camera works with the installed Photo Booth app, so it's possible.
Any thoughts on solving this situation would be appreciated.
Regards, Michaela
Avplayer encapsulates a player. After connecting to an Apple Bluetooth headset, it immediately reports an error. Non-Apple Bluetooth headsets can be played, but currently the issue is that the player works normally in one app but not in another. We are an educational app.
Device: iPhone 17 Pro
iOS Version: iOS 26.1
Camera: Ultra-wide (0.5x) using AVCaptureSession
Our camera app freezes on iPhone 17 when switching frame rates (30fps ↔ 60fps). This works fine on iPhone 16 Pro and earlier.
What We've Observed:
Freeze happens on frame rate change - particularly when stabilization was enabled
Thread.sleep is used - to allow camera hardware to settle before re-enabling stabilization
Works on older iPhones - only iPhone 17 exhibits this behavior
Console shows these errors before freeze:
17281
<<<< FigXPCUtilities >>>> signalled err=18446744073709534335 <<<< FigCaptureSourceRemote >>>> err=-17281
Is Thread.sleep on the main thread causing the freeze? Should all camera configuration be on a background queue?
Is there something specific about iPhone 17 ultra-wide camera that requires different handling?
Should we use session.beginConfiguration() / session.commitConfiguration() instead of direct device configuration?
Is calling setFrameRate from a property's didSet (which runs synchronously) problematic?
Are the FigCaptureSourceRemote errors (-17281) indicative of the problem, and what do they mean?
My workout watch app supports audio playback during exercise sessions.
When users carry both Apple Watch, iPhone, and AirPods, with AirPods connected to the iPhone, I want to route audio from Apple Watch to AirPods for playback. I've implemented this functionality using the following code.
try? session.setCategory(.playback, mode: .default, policy: .longFormAudio, options: [])
try await session.activate()
When users are playing music on iPhone and trigger my code in the watch app, Apple Watch correctly guides users to select
AirPods, pauses the iPhone's music, and plays my audio.
However, when playback finishes and I end the session using the code below:
try session.setActive(false, options:[.notifyOthersOnDeactivation])
the iPhone
doesn't automatically resume the previously interrupted music playback—it requires manual intervention.
Is this expected behavior, or am I missing other important steps in my code?
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Topic:
Media Technologies
SubTopic:
Audio
Is there any feasible way to get a Core Audio device's system effect status (Voice Isolation, Wide Spectrum)?
AVCaptureDevice provides convenience properties for system effects for video devices. I need to get this status for Core Audio input devices.
I'm trying to benchmark a Core Image filter chains memory footprint and notice a weird quirk in instruments.
On a real device, even with a simple Core Image chain, the memory balloons each time I ran the filter. See attached screen shots.
Running on iPhone 17 Pro:
Running on simulator (M2 Macbook Pro)
As you can see there's a huge build up of 4MB "VM: IOSurface" memory on the real device, but the simulator seems to clean it up correctly.
Here's my basic code:
func processImage() {
guard let inputImage = ContentViewModel.loadImageFromBundle(name: "kitty.HEIC") else {
print("Failed to load sample_image from bundle")
return
}
var outputImage = inputImage
outputImage = outputImage.applyingFilter("CIBloom", parameters: [
kCIInputRadiusKey: 20,
kCIInputIntensityKey: 0.8
])
DispatchQueue.global(qos: .userInitiated).async {
let data = self.context.jpegRepresentation(of: outputImage, colorSpace: CGColorSpace(name: CGColorSpace.sRGB)!)
if let data = data, let uiImage = UIImage(data: data) {
DispatchQueue.main.async {
self.displayImage = Image(uiImage: uiImage)
}
}
}
}
Why is this happening? Seems like a bug to me or I need to release an object. At the very least makes it challenging to measure memory usage.
Any help is greatly appreciated.
Alex
Hi,
We identified massive amounts of leaked memory with the tvOS 26 standard player user interface as soon as chapters (navigation markers) are involved.
Artwork images associated with chapters are not correctly released anymore, leaking memory in chunks of several MiBs.
Over time apps will be terminated by the system due to excessive memory consumption.
The issue was reported to Apple as tvOS 26 regression: Huge memory leaks associated with navigation marker artworks displayed in the tvOS standard user interface, filed under FB21160665.
hi all,
as soon an audio is played in a whatever app, coreaudiod inserts a sleep prevent assertion for both, the system AND the display.
can i somehow stop the insertion of the display sleep assertion?
pid 223(coreaudiod): [0x00004e9e00058dc2] 00:03:18 PreventUserIdleDisplaySleep named: "com.apple.audio.AppleGFXHDAEngineOutputDP:10001:0:{B31A-08C6-00000000}.context.preventuseridledisplaysleep"
Created for PID: 4145.
where PID 4145 is spotify.
but it doesn't matter which app is playing the audio.
any help would be appreciated
thanks
Topic:
Media Technologies
SubTopic:
Audio
I want to confirm if this is a bug or a programming error. Very easy to reproduce it by modifying AVCam sample code. Steps to reproduce:
Add AVCaptureVideoDataOutput to AVCaptureSession, no need to set delegate in AVCam sample code (CaptureService actor)
private let videoDataOutput = AVCaptureVideoDataOutput()
and then in configureSession method, add the following line
try addOutput(videoDataOutput)
if videoDataOutput.availableVideoPixelFormatTypes.contains(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) {
videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String : kCVPixelFormatType_420YpCbCr8BiPlanarFullRange]
}
And next modify set HDR method:
/// Sets whether the app captures HDR video.
func setHDRVideoEnabled(_ isEnabled: Bool) {
// Bracket the following configuration in a begin/commit configuration pair.
captureSession.beginConfiguration()
defer { captureSession.commitConfiguration() }
do {
// If the current device provides a 10-bit HDR format, enable it for use.
if isEnabled, let format = currentDevice.activeFormat10BitVariant {
try currentDevice.lockForConfiguration()
currentDevice.activeFormat = format
currentDevice.unlockForConfiguration()
isHDRVideoEnabled = true
if videoDataOutput.availableVideoPixelFormatTypes.contains(kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange) {
videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String : kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange]
}
} else {
captureSession.sessionPreset = .high
isHDRVideoEnabled = false
if videoDataOutput.availableVideoPixelFormatTypes.contains(kCVPixelFormatType_32BGRA) {
print("Setting sdr pixel format \(kCVPixelFormatType_32BGRA)")
videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String : kCVPixelFormatType_32BGRA]
}
try currentDevice.lockForConfiguration()
currentDevice.activeColorSpace = .sRGB
currentDevice.unlockForConfiguration()
}
} catch {
logger.error("Unable to obtain lock on device and can't enable HDR video capture.")
}
The problem now is toggling HDR on and off no longer works in video mode. If after setting HDR on, you set HDR to off, active format of device does not change (setting sessionPreset has no effect). This does not happen if video data output is not added to session.
Is there any workaround available?
Hi all,
Apple dropping on-going development for FireWire devices that were supported with the Core Audio driver standard is a catastrophe for a lot of struggling musicians who need to both keep up to date on security updates that come with new OS releases, and continue to utilise their hard earned investments in very expensive and still pristine audio devices that have been reduced to e-waste by Apple's seemingly tone-deaf ignorance in the cries for on-going support.
I have one of said audio devices, and I'd like to keep using it while keeping my 2019 Intel Mac Book Pro up to date with the latest security updates and OS features.
Probably not the first time you gurus have had someone make the logical leap leading to a request for something like this, but I was wondering if it might be somehow possible of shoe-horning the code used in previous versions of Mac OS that allowed the Mac to speak with the audio features of such devices to run inside the Ventura version of the OS.
Would it possible? Would it involve a lot of work? I don't think I'd be the only person willing to pay for a third party application or utility that restored this functionality.
There has to be 100's of thousands of people who would be happy to spare some cash to stop their multi-thousand dollar investment in gear to be so thoughtlessly resigned to the scrap heap.
Any comments or layman-friendly explanations as to why this couldn’t happen would be gratefully received!
Thanks,
em
Is it possible to find IDR frame (CMSampleBuffer) in AVAsset h264 video file?
Hey Swift community!
I'm exploring building a macOS app that needs to monitor what's currently playing in music apps like Spotify and Apple Music (track info, playback position, play/pause state). I'm trying to figure out the most efficient architecture before diving in.
The Goal:
Monitor playback state across multiple music players to react to changes in real-time, ideally with minimal CPU overhead since this would run continuously in the background.
Approaches I'm Considering
AppleScript / ScriptingBridge
Distributed Notifications
Native Frameworks (Apple Music only)
What's the recommended way to do this on macOS?
Are distributed notifications reliable enough to avoid polling entirely?
Is there a performance difference between AppleScript and ScriptingBridge for IPC?
For Apple Music specifically, should I use MusicKit, MediaPlayer, or stick with AppleScript?
Are there other approaches I'm missing?
Topic:
Media Technologies
SubTopic:
General
I believe this should work:
CFMutableDictionaryRef attrs = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
CFDictionaryAddValue(attrs, kCVImageBufferColorPrimariesKey, kCVImageBufferColorPrimaries_ITU_R_709_2);
CFDictionaryAddValue(attrs, kCVImageBufferTransferFunctionKey, kCVImageBufferTransferFunction_ITU_R_709_2);
CFDictionaryAddValue(attrs, kCVImageBufferYCbCrMatrixKey, kCVImageBufferYCbCrMatrix_ITU_R_709_2);
CVPixelBufferRef pixelBuffer = NULL;
CVPixelBufferCreate(kCFAllocatorDefault, width, height, kCVPixelFormatType_32ARGB, attrs, &pixelBuffer);
assert(CFDictionaryGetCount(CVBufferGetAttachments(pixelBuffer, kCVAttachmentMode_ShouldPropagate)) > 0);
But that last assert fails, so it appears the color info does not get attached.
kCVImageBufferColorPrimariesKey and the others are not one of the keys listed under BufferAttributeKeys, but I think they're supposed to be allowed because they're listed by CMVideoFormatDescriptionGetExtensionKeysCommonWithImageBuffers().
I'm hoping that putting the color matrix info in there will control how AVAssetWriter converts the RGB to YCbCr.
Topic:
Media Technologies
SubTopic:
Video
My app want Converting iphone12 HDR Video to SDR,to edit。
follow the doc Apple-HDR-Convert.
My code setting the pixBuffAttributes
[pixBuffAttributes setObject:(id)(kCVImageBufferYCbCrMatrix_ITU_R_709_2) forKey:(id)kCVImageBufferYCbCrMatrixKey];
[pixBuffAttributes setObject:(id)(kCVImageBufferColorPrimaries_ITU_R_709_2) forKey:(id)kCVImageBufferColorPrimariesKey];
[pixBuffAttributes setObject:(id)kCVImageBufferTransferFunction_ITU_R_709_2 forKey:(id)kCVImageBufferTransferFunctionKey];
playerItemOutput = [[AVPlayerItemVideoOutput alloc] initWithPixelBufferAttributes:pixBuffAttributes];
but I get the playerItemOutput's output buffer
CFTypeRef colorAttachments = CVBufferGetAttachment(pixelBuffer, kCVImageBufferYCbCrMatrixKey, NULL);
CFTypeRef colorPrimaries = CVBufferGetAttachment(pixelBuffer, kCVImageBufferColorPrimariesKey, NULL);
CFTypeRef colorTransFunc = CVBufferGetAttachment(pixelBuffer, kCVImageBufferTransferFunctionKey, NULL);
NSLog(@"colorAttachments = %@", colorAttachments);
NSLog(@"colorPrimaries = %@", colorPrimaries);
NSLog(@"colorTransFunc = %@", colorTransFunc);
log output:
colorAttachments = ITU_R_2020
colorPrimaries = ITU_R_2020
colorTransFunc = ITU_R_2100_HLG
pixBuffAttributes setting output format invalid,please help!
So experimenting with the new SpeechTranscriber, if I do:
let transcriber = SpeechTranscriber(
locale: locale,
transcriptionOptions: [],
reportingOptions: [.volatileResults],
attributeOptions: [.audioTimeRange]
)
only the final result has audio time ranges, not the volatile results.
Is this a performance consideration? If there is no performance problem, it would be nice to have the option to also get speech time ranges for volatile responses.
I'm not presenting the volatile text at all in the UI, I was just trying to keep statistics about the non-speech and the speech noise level, this way I can determine when the noise level falls under the noisefloor for a while.
The goal here was to finalize the recording automatically, when the noise level indicate that the user has finished speaking.