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AVAssetDownloadConfiguration: How many video variants are actually downloaded when multiple variants exist in the HLS master playlist?
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!
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Apple Music API Library Playlist Images
Hi, I'm sending an API request to: https://api.music.apple.com/v1/me/library/playlists?limit=$limit&offset=$offset To list all of the users library playlists, however the resulting objects do not contain the playlist artwork in the JSON. I've tried adding the extend and include attributes as well but to no avail. A partial example of the response: {"id": PLAYLIST_ID, "type": "library-playlists", "href": "/v1/me/library/playlists/PLAYLIST_ID", "attributes": {"lastModifiedDate": "2024-09-18T20:18:24Z", "canEdit": true, "name": "Afro Party Anthems", "isPublic": false, "description": {"standard": "Definitive African party starters"}, "hasCatalog": false, "dateAdded": "2022-03-10T18:30:56Z", "playParams": {"id": PLAYLIST_ID, "kind": "playlist", "isLibrary": true}}, "relationships": {"catalog": {"href": "/v1/me/library/playlists/PLAYLIST_ID/catalog", "data": []}}} Is there a way to get the artwork URL without sending a request for each playlist? And if not can this be fixed?
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Jun ’25
Improving Speech Analyzer Transcription for technical terms
I am developing an app with transcription and I am exploring ways to improve the transcription from the SpeechAnalyzer/Transcriber for technical terms. SFSpeech... recognition had the capability of being augmented by contextualStrings. Does something similar exist for SpeechAnalyzer/Transcriber? If so please point me towards the documentation and any sample code that may exist for this. If there are other options, please let me know.
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310
Sep ’25
AVAudioSession.outputVolume not reporting correctly in iOS 18+ devices
I’m using the shared instance of AVAudioSession. After activating it with .setActive(true), I observe the outputVolume, and it correctly reports the device’s volume. However, after deactivating the session using .setActive(false), changing the volume, and then reactivating it again, the outputVolume returns the previous volume (before deactivation), not the current device volume. The correct volume is only reported after the user manually changes it again using physical buttons or Control Center, which triggers the observer. What I need is a way to retrieve the actual current device volume immediately after reactivating the audio session, even on the second and subsequent activations. Disabling and re-enabling the audio session is essential to how my application functions. I’ve tested this behavior with my colleagues, and the issue is consistently reproducible on iOS 18.0.1, iOS 18.1, iOS 18.3, iOS 18.5 and iOS 18.6.2. On devices running iOS 17.6.1 and iOS 16.0.3, outputVolume correctly reflects the current volume immediately after calling .setActive(true) multiple times.
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Feb ’26
Inquiry regarding CoreMediaErrorDomain Code=-12880 in LL-HLS playback
Hello, I am developing a custom player SDK based on AVPlayer. While testing LL-HLS streams, I intermittently encounter the following error: Error Domain=CoreMediaErrorDomain Code=-12880 Since I cannot find documentation for this specific code, could you please clarify its meaning? 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. Any insights would be appreciated. Thank you.
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Feb ’26
AVCaptureMetadataOutput .face detection not working on iOS 26 Beta with high sessionPreset
In iOS 26 (Developer Beta), the AVCaptureMetadataOutputObjectsDelegate no longer receives callbacks when metadataOutput.metadataObjectTypes = [.face] is set. On earlier iOS versions the issue does not occur. Interestingly, face detection works if I set the sessionPreset to .medium, but not with .high — except on the iPhone 16 Pro Max, where it works regardless.
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Sep ’25
FairPlay: SDK4 vs SDK26 credentials/certificate for iOS/tvOS client apps
Hi We’re updating our KSM to support SPC v2/v3 and currently operate with both legacy SDK4 credentials (ASK + 1024 cert) and SDK26 credentials (certificate bundle + provisioning data + 1024/2048 keys). Our client apps run across a wide range of iOS/tvOS versions, so we want to follow Apple’s recommended client strategy for certificate selection. The docs describe SHA‑1 vs SHA‑256 in the SPC header, but do not specify which OS versions should use SDK4 vs SDK26 credentials. Could you clarify: Is there an official minimum iOS/tvOS version where you recommend SDK26 credentials for client apps? For older OS versions (e.g. iOS 15), is SDK4 still the recommended choice for client apps? Are there any official migration guidelines for client apps moving from SDK4 to SDK26 credentials? Thanks in advance.
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Feb ’26
VideoToolbox Encoder's Unregistered User Data SEI NAL UUID
I was advised to post here by a Code-Level Support representative. Below will be a copy of my initial issue report, and my minimally reproductive test project can be found at the following GitHub repository URL... https://github.com/PierceLBrooks/vtUudSeiNalCmake DESCRIPTION OF PROBLEM When encoding H264 video codec data using the VTCompressionSession API facilities available through the VideoToolbox framework on MacOS, the resultant bitstream will invariably include Unregistered User Data SEI NAL units that carry the UUID "47564adc-5c4c-433f-94ef-c5113cd143a8". The proprietary decoders we are working with currently struggle with filtering out these NAL units. Can you explain what purpose this serves, what the meaning of the byte-wise unit payloads are, and which configuration settings the VideoToolbox encoder instance specifically depends upon for triggering the insertion of them? STEPS TO REPRODUCE 1. Invoke the instantiation of a new VideoToolbox H264 encoder object by calling VTCompressionSessionCreate with appropriate configuration flags. 2. Push frames through the encoder, receiving their encoded byte buffer counterparts through an asynchronous callback. 3. Write that encoded data to some buffer which will contain the totality of the encoder's output. 4. Inspect the NAL units of the initial portion of this output bitstream buffer. 5. Observe the presence of at least one Unregistered User Data SEI NAL unit carrying the "47564adc-5c4c-433f-94ef-c5113cd143a8" UUID near the beginning of the output segment.
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Apr ’25
Unable to play audio via MusicKit
Hey folks, I'm running into an odd issue suddenly with an app that had a working MusicKit integration before. I'm using ApplicationMusicPlayer to play Apple Music albums and songs. I'm testing on a physical device, signed in to Apple ID, and with a valid subscription. Apple Music via the first-party app works entirely fine on this device. Attempting to play back any content at all gives the log: <ICUserIdentityStoreACAccountBackend: 0x1070bf3e0> Failed to initialize primary apple account, error=Error Domain=ICError Code=-7013 "Client is not entitled to access account store" UserInfo={NSDebugDescription=Client is not entitled to access account store} [ICUserIdentityStore] - initializing account histories with activeAccountDSID = nil, activeLockerAccountDSID = nil, timestamp = 14605951908 [ICUserIdentityStore] Failed to fetch local store account with error: Error Domain=ICError Code=-7013 "Client is not entitled to access account store" UserInfo={NSDebugDescription=Client is not entitled to access account store}. The album artwork, track names, etc, all appear in the control center playback controls, but the music doesn't play. Trying to trigger playback with control center just results in it skipping to the next track, which doesn't play either. This exact code used to work. I have the MusicKit service selected in Apple Connect. Since this isn't entitlement-based, I'm not sure how else to check that I'm set up correctly. I've tried deleting/reinstalling the app, restarting the device, cleaning/rebuilding, and deleting DerivedData, to no avail. Any help? Running Xcode 16.4 (16F6), testing on iOS 18.5 (22F76)
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Jun ’25
Audio DSP Processing Issue / Metallic Ringing Artifacts when recording acoustic instruments on iPhone 17 Pro Max
Description: I have identified a specific issue when recording acoustic guitar and other instruments on the iPhone 17 Pro Max using native applications (Voice Memos, Camera). The recordings contain an unnatural metallic resonance (ringing artifacts) that should not be present. Testing and Methodology: Hardware Verification: Initially, I suspected a hardware defect in the audio chip or microphone. However, extensive testing with third-party software suggests this is likely a software-level issue. AudioShare Test: I conducted a test using the AudioShare app in "Measurement Mode" (which bypasses standard iOS system-wide audio processing). In this mode, the audio remains perfectly clean, and the metallic ringing disappears entirely. Conclusion: The issue is rooted in the DSP (Digital Signal Processing) algorithms that iOS applies for noise suppression or voice enhancement. These algorithms appear to misinterpret the high-frequency overtones of acoustic instruments as background noise and attempt to "filter" them, resulting in audible digital artifacts. Comparison Results: This issue has not been observed on devices from other brands or on older iPhone models (preliminary tests suggest older versions handle this better). Notably, the problem persists even in GarageBand, as the app still utilizes certain system-level processing layers. Proposed Solution: I suggest adding a "Raw Audio" or "Instrument Mode" toggle within the Microphone/Audio settings for native apps. This mode should disable aggressive DSP processing, similar to how the AVAudioSession.Mode.measurement works in specialized apps. Attachments: I am attaching 4 archives, including a final "Measurement Mode" folder with comparative samples (Measurement Mode vs. Standard Mode). The artifacts are most prominent when monitored through headphones.
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Jan ’26
is the output frame rate of a CMIOExtension rounded or capped?
I made a CMIOExtension (a virtual camera) which generates its own output, for use in our in-house software testing. I wanted to make a video source with 29.97, 30, 59.94 and 60fps output. To this end, I created a CMIOExtensionDeviceSource which creates a CMIOExtensionDevice with one CMIOExtensionStreamSource with various stream formats contained in [CMIOExtensionStreamFormat], including one with both maxFrameDuration and minFrameDuration = CMTimeMake(value: 1000, timescale: 30000) and another with both maxFrameDuration and minFrameDuration = CMTimeMake(value: 1001, timescale: 30000) I've held off on the creation of the 59.94/60fps source for now until this problem is resolved. my virtual camera works, it produces a signal, but when I examine its associated AVCaptureDevice in the debugger, I find (lldb) po self.captureDevice?.formats[0].videoSupportedFrameRateRanges[0].maxFrameDuration ▿ Optional<CMTime> ▿ some : CMTime - value : 1000000 - timescale : 30000000 ▿ flags : CMTimeFlags - rawValue : 1 - epoch : 0 I get the same value, 1000000/30000000, or exactly 30fps, for all the formats of my AVCaptureDevice. Is there something I'm doing wrong, or do CMIOExtensionDevices always round the frame rates? I can't force CoreMediaIO to produce frames at exactly my desired frame interval, but I'd like to ensure that the average frame rate is my desired rate. How can I do that? Frame emission is governed by a repeating DispatchSourceTimer with a repeat time specified in nanoseconds with the TimerFlags set to 'strict'.
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Jan ’26
Live Photos created with PHLivePhoto API show "Motion not available" when setting as wallpaper
I'm creating Live Photos programmatically in my app using the Photos and AVFoundation frameworks. While the Live Photos work perfectly in the Photos app (long press shows motion), users cannot set them as motion wallpapers. The system shows "Motion not available" message. Here's my approach for creating Live Photos: // 1. Create video with required metadata let writer = try AVAssetWriter(outputURL: videoURL, fileType: .mov) let contentIdentifier = AVMutableMetadataItem() contentIdentifier.identifier = .quickTimeMetadataContentIdentifier contentIdentifier.value = assetIdentifier as NSString writer.metadata = [contentIdentifier] // Video settings: 882x1920, H.264, 30fps, 2 seconds // Added still-image-time metadata at middle frame // 2. Create HEIC image with asset identifier var makerAppleDict: [String: Any] = [:] makerAppleDict["17"] = assetIdentifier // Required key for Live Photo metadata[kCGImagePropertyMakerAppleDictionary as String] = makerAppleDict // 3. Generate Live Photo PHLivePhoto.request( withResourceFileURLs: [photoURL, videoURL], placeholderImage: nil, targetSize: .zero, contentMode: .aspectFit ) { livePhoto, info in // Success - Live Photo created } // 4. Save to Photos library PHAssetCreationRequest.forAsset().addResource(with: .photo, fileURL: photoURL, options: nil) PHAssetCreationRequest.forAsset().addResource(with: .pairedVideo, fileURL: videoURL, options: nil) What I've Tried Matching exact video specifications from Camera app (882x1920, H.264, 30fps) Adding all documented metadata (content identifier, still-image-time) Testing various video durations (1.5s, 2s, 3s) Different image formats (HEIC, JPEG) Comparing with exiftool against working Live Photos Expected Behavior Live Photos created programmatically should be eligible for motion wallpapers, just like those from the Camera app. Actual Behavior System shows "Motion not available" and only allows setting as static wallpaper. Any insights or workarounds would be greatly appreciated. This is affecting our users who want to use their created content as wallpapers. Questions Are there additional undocumented requirements for Live Photos to be wallpaper-eligible? Is this a deliberate restriction for third-party apps, or a bug? Has anyone successfully created Live Photos that work as motion wallpapers? Environment iOS 17.0 - 18.1 Xcode 16.0 Tested on iPhone 16 Pro
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Aug ’25
MusicKit - ApplicationMusicPlayer fails to play certain Songs
[Note: this issue was happening on a main testing device, and after testing the same code on other devices, this issue is only happening on 1 out of 4 devices] We are successfully getting a MusicCatalogResourceResponse for every song ID where we make the MusicCatalogResourceRequest. We are able to display the song title, artist name, and album artwork for each Song in the response. However - when we go to play the song, there are some songs that play, and several songs that do not play. For the songs that don't play, the console shows “Failed to prepareToPlay error=<MPMusicPlayerControllerErrorDomain.6 "Failed to prepare to play" {}>” let musicPlayer = ApplicationMusicPlayer.shared func playSong(_ song: Song) { musicPlayer.queue = [song] Task { try await musicPlayer.prepareToPlay() try await musicPlayer.play() } Is there anything else we can investigate about what may be causing specific song IDs not to play on this specific device? Even if we remove line 6 musicPlayer.prepareToPlay() we still see the same console error when running playSong with the Songs that don't work. It is always the same song IDs that we can play and always the same song IDs that we cannot get to play, even trying them across different projects with different bundle identifiers. We can tap to play a song that works, and it starts playing immediately. Then tap a song that doesn't work, and nothing happens. Then back to a song that works. It's consistent which songs succeed and fail on this device. Perhaps there is an issue specific to this very iPad when it comes to certain specific songs, but we'd like to be confident that an app relying on MusicKit will be able to play songs that have been successfully loaded with a MusicCatalogResourceResponse. Thanks for any help or suggestions about what we may be able to investigate further on the device or what we should consider when launching an app that expects anyone with Apple Music to be able to listen to any of the songs loaded by the app. Specific iPad details: iPad Pro (12.9-inch) (6th generation) running iPadOS 26.4 Beta Two of the song IDs that won't play on this iPad (even though we can access and display their album artwork and all other information): 943204000 and 1441164805
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-46250 error when calling `makeSecureTokenForExpirationDateOfPersistableContentKey`
Hi there, We're working on offline playback of DRM tracks. The persistent keys (also known as track licenses) for offline playback are stored locally on the device and are served from cache when a user initiates playback of a downloaded track. Our persistent keys have a limited validity time and need to be refreshed when they expire. To prevent a situation where a persistent key expires while the user is offline, we've decided to eagerly refresh these keys one week before their expiration date. To make that happen we need to be able to obtain the expiration date of the given track license. We've been attempting to use the makeSecureTokenForExpirationDateOfPersistableContentKey API to facilitate this process. The documentation states that this API returns a secret token representing the persistent key, which we can then exchange with our license server for the expiration date: https://developer.apple.com/documentation/avfoundation/avcontentkeysession/makesecuretokenforexpirationdate(ofpersistablecontentkey:completionhandler:)?language=objc However, every time we call makeSecureTokenForExpirationDateOfPersistableContentKey, we receive an error with code -46250. We haven't been able to find any public references or documentation for this specific error code, which is preventing us from troubleshooting the issue. We are conducting our tests on a physical device, as the simulator does not support FairPlay playback. We don't use dual expiry approach. Is our understanding of how to obtain the expiration timestamp correct? Are we using the makeSecureTokenForExpirationDateOfPersistableContentKey API as it was intended? What does the -46250 error code mean, and what steps should we take to fix our FairPlay implementation to make this work? Thanks in advance for your assistance.
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Jan ’26
AsyncPublisher for AVPlayerItem not working
Hello, I'm trying to subscribe to AVPlayerItem status updates using Combine and it's bridge to Swift Concurrency – .values. This is my sample code. struct ContentView: View { @State var player: AVPlayer? @State var loaded = false var body: some View { VStack { if let player { Text("loading status: \(loaded)") Spacer() VideoPlayer(player: player) Button("Load") { Task { let item = AVPlayerItem( url: URL(string: "https://sample-videos.com/video321/mp4/360/big_buck_bunny_360p_5mb.mp4")! ) player.replaceCurrentItem(with: item) let publisher = player.publisher(for: \.status) for await status in publisher.values { print(status.rawValue) if status == .readyToPlay { loaded = true break } } print("we are out") } } } else { Text("No video selected") } } .task { player = AVPlayer() } } } After I click on the "load" button it prints out 0 (as the initial status of .unknown) and nothing after – even when the video is fully loaded. At the same time this works as expected (loading status is set to true): struct ContentView: View { @State var player: AVPlayer? @State var loaded = false @State var cancellable: AnyCancellable? var body: some View { VStack { if let player { Text("loading status: \(loaded)") Spacer() VideoPlayer(player: player) Button("Load") { Task { let item = AVPlayerItem( url: URL(string: "https://sample-videos.com/video321/mp4/360/big_buck_bunny_360p_5mb.mp4")! ) player.replaceCurrentItem(with: item) let stream = AsyncStream { continuation in cancellable = item.publisher(for: \.status) .sink { if $0 == .readyToPlay { continuation.yield($0) continuation.finish() } } } for await _ in stream { loaded = true cancellable?.cancel() cancellable = nil break } } } } else { Text("No video selected") } } .task { player = AVPlayer() } } } Is this a bug or something?
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211
Jun ’25
PhotosPickerItem.itemIdentifier always nil
I'm using the SwiftUI Photos Picker to select videos from the users Photos library and then opening the video using the PhotosPickerItem. I'm looking for a way to allow the user to open the same video on their other devices as the app uses SwiftData and CloudKit to provide access to a recently watched list of videos. The URL from the PhotosPickerItem appears to be device specific and so I was looking to see if I can use the itemIdentifier and then the init that takes the itemIdentifier to create the PhotosPickerItem on the other devices. The itemIdentifier however is always nil and so wouldn't be able to be used in this way. Is there an alternative approach whereby the users can open a video using a PhotosPickerItem and that item would be viewable on their other devices with an item identifier or a URL that is device agnostic. This approach should also not involve copying the video into other storage as it would simply expand the use of the users iCloud storage, providing a less than ideal user experience. If the user has opened the video from their Photos library, there should be a way to allow the same user (e.g. same Apple ID), to use the same app on another device to open the video again.
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Nov ’25
Apple Music playlist create/delete works but DELETE returns 401 — and MusicKit write APIs are macOS‑unavailable. How to build a playlist editor on macOS?
I’m trying to build a playlist editor on macOS. I can create playlists via the Apple Music HTTP API, but DELETE always returns 401 even immediately after creation with the same tokens. Minimal repro: #!/usr/bin/env bash set -euo pipefail BASE_URL="https://api.music.apple.com/v1" PLAYLIST_NAME="${PLAYLIST_NAME:-blah}" : "${APPLE_MUSIC_DEV_TOKEN:?}" : "${APPLE_MUSIC_USER_TOKEN:?}" create_body="$(mktemp)" delete_body="$(mktemp)" trap 'rm -f "$create_body" "$delete_body"' EXIT curl -sS --compressed -o "$create_body" -w "Create status: %{http_code}\n" \ -X POST "${BASE_URL}/me/library/playlists" \ -H "Authorization: Bearer ${APPLE_MUSIC_DEV_TOKEN}" \ -H "Music-User-Token: ${APPLE_MUSIC_USER_TOKEN}" \ -H "Content-Type: application/json" \ -d "{\"attributes\":{\"name\":\"${PLAYLIST_NAME}\"}}" playlist_id="$(python3 - "$create_body" <<'PY' import json, sys with open(sys.argv[1], "r", encoding="utf-8") as f: data = json.load(f) print(data["data"][0]["id"]) PY )" curl -sS --compressed -o "$delete_body" -w "Delete status: %{http_code}\n" \ -X DELETE "${BASE_URL}/me/library/playlists/${playlist_id}" \ -H "Authorization: Bearer ${APPLE_MUSIC_DEV_TOKEN}" \ -H "Music-User-Token: ${APPLE_MUSIC_USER_TOKEN}" \ -H "Content-Type: application/json" I capture the response bodies like this: cat "$create_body" cat "$delete_body" Result: Create: 201 Delete: 401 I also checked the latest macOS SDK’s MusicKit interfaces and MusicLibrary.createPlaylist/edit/add(to:) are marked @available(macOS, unavailable), so I can’t create/ delete via MusicKit on macOS either. Question: How can I implement a playlist editor on macOS (create/delete/modify) if: MusicKit write APIs are unavailable on macOS, and The HTTP API can create but DELETE returns 401? Any guidance or official workaround would be hugely appreciated.
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Jan ’26
Indicate Packet Loss With AVAudioConverter for OPUS Decoding
I'm using an AVAudioConverter object to decode an OPUS stream for VoIP. The decoding itself works well, however, whenever the stream stalls (no more audio packet is available to decode because of network instability) this can be heard in crackling / abrupt stop in decoded audio. OPUS can mitigate this by indicating packet loss by passing a null pointer in the C-library to int opus_decode_float (OpusDecoder * st, const unsigned char * data, opus_int32 len, float * pcm, int frame_size, int decode_fec), see https://opus-codec.org/docs/opus_api-1.2/group__opus__decoder.html#ga9c554b8c0214e24733a299fe53bb3bd2. However, with AVAudioConverter using Swift I'm constructing an AVAudioCompressedBuffer like so:         let compressedBuffer = AVAudioCompressedBuffer(             format: VoiceEncoder.Constants.networkFormat,             packetCapacity: 1,             maximumPacketSize: data.count         )         compressedBuffer.byteLength = UInt32(data.count)         compressedBuffer.packetCount = 1   compressedBuffer.packetDescriptions! .pointee.mDataByteSize = UInt32(data.count)         data.copyBytes(             to: compressedBuffer.data .assumingMemoryBound(to: UInt8.self),             count: data.count         ) where data: Data contains the raw OPUS frame to be decoded. How can I specify data loss in this context and cause the AVAudioConverter to output PCM data whenever no more input data is available? More context: I'm specifying the audio format like this:         static let frameSize: UInt32 = 960         static let sampleRate: Float64 = 48000.0         static var networkFormatStreamDescription = AudioStreamBasicDescription(             mSampleRate: sampleRate,             mFormatID: kAudioFormatOpus,             mFormatFlags: 0,             mBytesPerPacket: 0,             mFramesPerPacket: frameSize,             mBytesPerFrame: 0,             mChannelsPerFrame: 1,             mBitsPerChannel: 0,             mReserved: 0         )         static let networkFormat = AVAudioFormat( streamDescription: &networkFormatStreamDescription )! I've tried 1) setting byteLength and packetCount to zero and 2) returning nil but setting .haveData in the AVAudioConverterInputBlock I'm using with no success.
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924
May ’25
AVAssetDownloadConfiguration: How many video variants are actually downloaded when multiple variants exist in the HLS master playlist?
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!
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283
Activity
3w
Apple Music API Library Playlist Images
Hi, I'm sending an API request to: https://api.music.apple.com/v1/me/library/playlists?limit=$limit&offset=$offset To list all of the users library playlists, however the resulting objects do not contain the playlist artwork in the JSON. I've tried adding the extend and include attributes as well but to no avail. A partial example of the response: {"id": PLAYLIST_ID, "type": "library-playlists", "href": "/v1/me/library/playlists/PLAYLIST_ID", "attributes": {"lastModifiedDate": "2024-09-18T20:18:24Z", "canEdit": true, "name": "Afro Party Anthems", "isPublic": false, "description": {"standard": "Definitive African party starters"}, "hasCatalog": false, "dateAdded": "2022-03-10T18:30:56Z", "playParams": {"id": PLAYLIST_ID, "kind": "playlist", "isLibrary": true}}, "relationships": {"catalog": {"href": "/v1/me/library/playlists/PLAYLIST_ID/catalog", "data": []}}} Is there a way to get the artwork URL without sending a request for each playlist? And if not can this be fixed?
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1
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124
Activity
Jun ’25
Improving Speech Analyzer Transcription for technical terms
I am developing an app with transcription and I am exploring ways to improve the transcription from the SpeechAnalyzer/Transcriber for technical terms. SFSpeech... recognition had the capability of being augmented by contextualStrings. Does something similar exist for SpeechAnalyzer/Transcriber? If so please point me towards the documentation and any sample code that may exist for this. If there are other options, please let me know.
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1
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310
Activity
Sep ’25
AVAudioSession.outputVolume not reporting correctly in iOS 18+ devices
I’m using the shared instance of AVAudioSession. After activating it with .setActive(true), I observe the outputVolume, and it correctly reports the device’s volume. However, after deactivating the session using .setActive(false), changing the volume, and then reactivating it again, the outputVolume returns the previous volume (before deactivation), not the current device volume. The correct volume is only reported after the user manually changes it again using physical buttons or Control Center, which triggers the observer. What I need is a way to retrieve the actual current device volume immediately after reactivating the audio session, even on the second and subsequent activations. Disabling and re-enabling the audio session is essential to how my application functions. I’ve tested this behavior with my colleagues, and the issue is consistently reproducible on iOS 18.0.1, iOS 18.1, iOS 18.3, iOS 18.5 and iOS 18.6.2. On devices running iOS 17.6.1 and iOS 16.0.3, outputVolume correctly reflects the current volume immediately after calling .setActive(true) multiple times.
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3
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342
Activity
Feb ’26
Inquiry regarding CoreMediaErrorDomain Code=-12880 in LL-HLS playback
Hello, I am developing a custom player SDK based on AVPlayer. While testing LL-HLS streams, I intermittently encounter the following error: Error Domain=CoreMediaErrorDomain Code=-12880 Since I cannot find documentation for this specific code, could you please clarify its meaning? 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. Any insights would be appreciated. Thank you.
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1
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173
Activity
Feb ’26
Is it possible to stream video from a UVC (USB Video Class) camera on an iPhone 15?
Is it possible to stream video from a UVC (USB Video Class) camera on an iPhone 15? If so, are there any specific hardware or software requirements to enable this functionality?
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3
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1
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192
Activity
Apr ’25
AVCaptureMetadataOutput .face detection not working on iOS 26 Beta with high sessionPreset
In iOS 26 (Developer Beta), the AVCaptureMetadataOutputObjectsDelegate no longer receives callbacks when metadataOutput.metadataObjectTypes = [.face] is set. On earlier iOS versions the issue does not occur. Interestingly, face detection works if I set the sessionPreset to .medium, but not with .high — except on the iPhone 16 Pro Max, where it works regardless.
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2
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368
Activity
Sep ’25
FairPlay: SDK4 vs SDK26 credentials/certificate for iOS/tvOS client apps
Hi We’re updating our KSM to support SPC v2/v3 and currently operate with both legacy SDK4 credentials (ASK + 1024 cert) and SDK26 credentials (certificate bundle + provisioning data + 1024/2048 keys). Our client apps run across a wide range of iOS/tvOS versions, so we want to follow Apple’s recommended client strategy for certificate selection. The docs describe SHA‑1 vs SHA‑256 in the SPC header, but do not specify which OS versions should use SDK4 vs SDK26 credentials. Could you clarify: Is there an official minimum iOS/tvOS version where you recommend SDK26 credentials for client apps? For older OS versions (e.g. iOS 15), is SDK4 still the recommended choice for client apps? Are there any official migration guidelines for client apps moving from SDK4 to SDK26 credentials? Thanks in advance.
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2
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263
Activity
Feb ’26
VideoToolbox Encoder's Unregistered User Data SEI NAL UUID
I was advised to post here by a Code-Level Support representative. Below will be a copy of my initial issue report, and my minimally reproductive test project can be found at the following GitHub repository URL... https://github.com/PierceLBrooks/vtUudSeiNalCmake DESCRIPTION OF PROBLEM When encoding H264 video codec data using the VTCompressionSession API facilities available through the VideoToolbox framework on MacOS, the resultant bitstream will invariably include Unregistered User Data SEI NAL units that carry the UUID "47564adc-5c4c-433f-94ef-c5113cd143a8". The proprietary decoders we are working with currently struggle with filtering out these NAL units. Can you explain what purpose this serves, what the meaning of the byte-wise unit payloads are, and which configuration settings the VideoToolbox encoder instance specifically depends upon for triggering the insertion of them? STEPS TO REPRODUCE 1. Invoke the instantiation of a new VideoToolbox H264 encoder object by calling VTCompressionSessionCreate with appropriate configuration flags. 2. Push frames through the encoder, receiving their encoded byte buffer counterparts through an asynchronous callback. 3. Write that encoded data to some buffer which will contain the totality of the encoder's output. 4. Inspect the NAL units of the initial portion of this output bitstream buffer. 5. Observe the presence of at least one Unregistered User Data SEI NAL unit carrying the "47564adc-5c4c-433f-94ef-c5113cd143a8" UUID near the beginning of the output segment.
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256
Activity
Apr ’25
Unable to play audio via MusicKit
Hey folks, I'm running into an odd issue suddenly with an app that had a working MusicKit integration before. I'm using ApplicationMusicPlayer to play Apple Music albums and songs. I'm testing on a physical device, signed in to Apple ID, and with a valid subscription. Apple Music via the first-party app works entirely fine on this device. Attempting to play back any content at all gives the log: <ICUserIdentityStoreACAccountBackend: 0x1070bf3e0> Failed to initialize primary apple account, error=Error Domain=ICError Code=-7013 "Client is not entitled to access account store" UserInfo={NSDebugDescription=Client is not entitled to access account store} [ICUserIdentityStore] - initializing account histories with activeAccountDSID = nil, activeLockerAccountDSID = nil, timestamp = 14605951908 [ICUserIdentityStore] Failed to fetch local store account with error: Error Domain=ICError Code=-7013 "Client is not entitled to access account store" UserInfo={NSDebugDescription=Client is not entitled to access account store}. The album artwork, track names, etc, all appear in the control center playback controls, but the music doesn't play. Trying to trigger playback with control center just results in it skipping to the next track, which doesn't play either. This exact code used to work. I have the MusicKit service selected in Apple Connect. Since this isn't entitlement-based, I'm not sure how else to check that I'm set up correctly. I've tried deleting/reinstalling the app, restarting the device, cleaning/rebuilding, and deleting DerivedData, to no avail. Any help? Running Xcode 16.4 (16F6), testing on iOS 18.5 (22F76)
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174
Activity
Jun ’25
Audio DSP Processing Issue / Metallic Ringing Artifacts when recording acoustic instruments on iPhone 17 Pro Max
Description: I have identified a specific issue when recording acoustic guitar and other instruments on the iPhone 17 Pro Max using native applications (Voice Memos, Camera). The recordings contain an unnatural metallic resonance (ringing artifacts) that should not be present. Testing and Methodology: Hardware Verification: Initially, I suspected a hardware defect in the audio chip or microphone. However, extensive testing with third-party software suggests this is likely a software-level issue. AudioShare Test: I conducted a test using the AudioShare app in "Measurement Mode" (which bypasses standard iOS system-wide audio processing). In this mode, the audio remains perfectly clean, and the metallic ringing disappears entirely. Conclusion: The issue is rooted in the DSP (Digital Signal Processing) algorithms that iOS applies for noise suppression or voice enhancement. These algorithms appear to misinterpret the high-frequency overtones of acoustic instruments as background noise and attempt to "filter" them, resulting in audible digital artifacts. Comparison Results: This issue has not been observed on devices from other brands or on older iPhone models (preliminary tests suggest older versions handle this better). Notably, the problem persists even in GarageBand, as the app still utilizes certain system-level processing layers. Proposed Solution: I suggest adding a "Raw Audio" or "Instrument Mode" toggle within the Microphone/Audio settings for native apps. This mode should disable aggressive DSP processing, similar to how the AVAudioSession.Mode.measurement works in specialized apps. Attachments: I am attaching 4 archives, including a final "Measurement Mode" folder with comparative samples (Measurement Mode vs. Standard Mode). The artifacts are most prominent when monitored through headphones.
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161
Activity
Jan ’26
is the output frame rate of a CMIOExtension rounded or capped?
I made a CMIOExtension (a virtual camera) which generates its own output, for use in our in-house software testing. I wanted to make a video source with 29.97, 30, 59.94 and 60fps output. To this end, I created a CMIOExtensionDeviceSource which creates a CMIOExtensionDevice with one CMIOExtensionStreamSource with various stream formats contained in [CMIOExtensionStreamFormat], including one with both maxFrameDuration and minFrameDuration = CMTimeMake(value: 1000, timescale: 30000) and another with both maxFrameDuration and minFrameDuration = CMTimeMake(value: 1001, timescale: 30000) I've held off on the creation of the 59.94/60fps source for now until this problem is resolved. my virtual camera works, it produces a signal, but when I examine its associated AVCaptureDevice in the debugger, I find (lldb) po self.captureDevice?.formats[0].videoSupportedFrameRateRanges[0].maxFrameDuration ▿ Optional<CMTime> ▿ some : CMTime - value : 1000000 - timescale : 30000000 ▿ flags : CMTimeFlags - rawValue : 1 - epoch : 0 I get the same value, 1000000/30000000, or exactly 30fps, for all the formats of my AVCaptureDevice. Is there something I'm doing wrong, or do CMIOExtensionDevices always round the frame rates? I can't force CoreMediaIO to produce frames at exactly my desired frame interval, but I'd like to ensure that the average frame rate is my desired rate. How can I do that? Frame emission is governed by a repeating DispatchSourceTimer with a repeat time specified in nanoseconds with the TimerFlags set to 'strict'.
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710
Activity
Jan ’26
Live Photos created with PHLivePhoto API show "Motion not available" when setting as wallpaper
I'm creating Live Photos programmatically in my app using the Photos and AVFoundation frameworks. While the Live Photos work perfectly in the Photos app (long press shows motion), users cannot set them as motion wallpapers. The system shows "Motion not available" message. Here's my approach for creating Live Photos: // 1. Create video with required metadata let writer = try AVAssetWriter(outputURL: videoURL, fileType: .mov) let contentIdentifier = AVMutableMetadataItem() contentIdentifier.identifier = .quickTimeMetadataContentIdentifier contentIdentifier.value = assetIdentifier as NSString writer.metadata = [contentIdentifier] // Video settings: 882x1920, H.264, 30fps, 2 seconds // Added still-image-time metadata at middle frame // 2. Create HEIC image with asset identifier var makerAppleDict: [String: Any] = [:] makerAppleDict["17"] = assetIdentifier // Required key for Live Photo metadata[kCGImagePropertyMakerAppleDictionary as String] = makerAppleDict // 3. Generate Live Photo PHLivePhoto.request( withResourceFileURLs: [photoURL, videoURL], placeholderImage: nil, targetSize: .zero, contentMode: .aspectFit ) { livePhoto, info in // Success - Live Photo created } // 4. Save to Photos library PHAssetCreationRequest.forAsset().addResource(with: .photo, fileURL: photoURL, options: nil) PHAssetCreationRequest.forAsset().addResource(with: .pairedVideo, fileURL: videoURL, options: nil) What I've Tried Matching exact video specifications from Camera app (882x1920, H.264, 30fps) Adding all documented metadata (content identifier, still-image-time) Testing various video durations (1.5s, 2s, 3s) Different image formats (HEIC, JPEG) Comparing with exiftool against working Live Photos Expected Behavior Live Photos created programmatically should be eligible for motion wallpapers, just like those from the Camera app. Actual Behavior System shows "Motion not available" and only allows setting as static wallpaper. Any insights or workarounds would be greatly appreciated. This is affecting our users who want to use their created content as wallpapers. Questions Are there additional undocumented requirements for Live Photos to be wallpaper-eligible? Is this a deliberate restriction for third-party apps, or a bug? Has anyone successfully created Live Photos that work as motion wallpapers? Environment iOS 17.0 - 18.1 Xcode 16.0 Tested on iPhone 16 Pro
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453
Activity
Aug ’25
MusicKit - ApplicationMusicPlayer fails to play certain Songs
[Note: this issue was happening on a main testing device, and after testing the same code on other devices, this issue is only happening on 1 out of 4 devices] We are successfully getting a MusicCatalogResourceResponse for every song ID where we make the MusicCatalogResourceRequest. We are able to display the song title, artist name, and album artwork for each Song in the response. However - when we go to play the song, there are some songs that play, and several songs that do not play. For the songs that don't play, the console shows “Failed to prepareToPlay error=<MPMusicPlayerControllerErrorDomain.6 "Failed to prepare to play" {}>” let musicPlayer = ApplicationMusicPlayer.shared func playSong(_ song: Song) { musicPlayer.queue = [song] Task { try await musicPlayer.prepareToPlay() try await musicPlayer.play() } Is there anything else we can investigate about what may be causing specific song IDs not to play on this specific device? Even if we remove line 6 musicPlayer.prepareToPlay() we still see the same console error when running playSong with the Songs that don't work. It is always the same song IDs that we can play and always the same song IDs that we cannot get to play, even trying them across different projects with different bundle identifiers. We can tap to play a song that works, and it starts playing immediately. Then tap a song that doesn't work, and nothing happens. Then back to a song that works. It's consistent which songs succeed and fail on this device. Perhaps there is an issue specific to this very iPad when it comes to certain specific songs, but we'd like to be confident that an app relying on MusicKit will be able to play songs that have been successfully loaded with a MusicCatalogResourceResponse. Thanks for any help or suggestions about what we may be able to investigate further on the device or what we should consider when launching an app that expects anyone with Apple Music to be able to listen to any of the songs loaded by the app. Specific iPad details: iPad Pro (12.9-inch) (6th generation) running iPadOS 26.4 Beta Two of the song IDs that won't play on this iPad (even though we can access and display their album artwork and all other information): 943204000 and 1441164805
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200
Activity
3w
Configuring capture pipeline with ProResRAW codec
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?
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3
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0
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1.2k
Activity
Feb ’26
-46250 error when calling `makeSecureTokenForExpirationDateOfPersistableContentKey`
Hi there, We're working on offline playback of DRM tracks. The persistent keys (also known as track licenses) for offline playback are stored locally on the device and are served from cache when a user initiates playback of a downloaded track. Our persistent keys have a limited validity time and need to be refreshed when they expire. To prevent a situation where a persistent key expires while the user is offline, we've decided to eagerly refresh these keys one week before their expiration date. To make that happen we need to be able to obtain the expiration date of the given track license. We've been attempting to use the makeSecureTokenForExpirationDateOfPersistableContentKey API to facilitate this process. The documentation states that this API returns a secret token representing the persistent key, which we can then exchange with our license server for the expiration date: https://developer.apple.com/documentation/avfoundation/avcontentkeysession/makesecuretokenforexpirationdate(ofpersistablecontentkey:completionhandler:)?language=objc However, every time we call makeSecureTokenForExpirationDateOfPersistableContentKey, we receive an error with code -46250. We haven't been able to find any public references or documentation for this specific error code, which is preventing us from troubleshooting the issue. We are conducting our tests on a physical device, as the simulator does not support FairPlay playback. We don't use dual expiry approach. Is our understanding of how to obtain the expiration timestamp correct? Are we using the makeSecureTokenForExpirationDateOfPersistableContentKey API as it was intended? What does the -46250 error code mean, and what steps should we take to fix our FairPlay implementation to make this work? Thanks in advance for your assistance.
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2
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383
Activity
Jan ’26
AsyncPublisher for AVPlayerItem not working
Hello, I'm trying to subscribe to AVPlayerItem status updates using Combine and it's bridge to Swift Concurrency – .values. This is my sample code. struct ContentView: View { @State var player: AVPlayer? @State var loaded = false var body: some View { VStack { if let player { Text("loading status: \(loaded)") Spacer() VideoPlayer(player: player) Button("Load") { Task { let item = AVPlayerItem( url: URL(string: "https://sample-videos.com/video321/mp4/360/big_buck_bunny_360p_5mb.mp4")! ) player.replaceCurrentItem(with: item) let publisher = player.publisher(for: \.status) for await status in publisher.values { print(status.rawValue) if status == .readyToPlay { loaded = true break } } print("we are out") } } } else { Text("No video selected") } } .task { player = AVPlayer() } } } After I click on the "load" button it prints out 0 (as the initial status of .unknown) and nothing after – even when the video is fully loaded. At the same time this works as expected (loading status is set to true): struct ContentView: View { @State var player: AVPlayer? @State var loaded = false @State var cancellable: AnyCancellable? var body: some View { VStack { if let player { Text("loading status: \(loaded)") Spacer() VideoPlayer(player: player) Button("Load") { Task { let item = AVPlayerItem( url: URL(string: "https://sample-videos.com/video321/mp4/360/big_buck_bunny_360p_5mb.mp4")! ) player.replaceCurrentItem(with: item) let stream = AsyncStream { continuation in cancellable = item.publisher(for: \.status) .sink { if $0 == .readyToPlay { continuation.yield($0) continuation.finish() } } } for await _ in stream { loaded = true cancellable?.cancel() cancellable = nil break } } } } else { Text("No video selected") } } .task { player = AVPlayer() } } } Is this a bug or something?
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211
Activity
Jun ’25
PhotosPickerItem.itemIdentifier always nil
I'm using the SwiftUI Photos Picker to select videos from the users Photos library and then opening the video using the PhotosPickerItem. I'm looking for a way to allow the user to open the same video on their other devices as the app uses SwiftData and CloudKit to provide access to a recently watched list of videos. The URL from the PhotosPickerItem appears to be device specific and so I was looking to see if I can use the itemIdentifier and then the init that takes the itemIdentifier to create the PhotosPickerItem on the other devices. The itemIdentifier however is always nil and so wouldn't be able to be used in this way. Is there an alternative approach whereby the users can open a video using a PhotosPickerItem and that item would be viewable on their other devices with an item identifier or a URL that is device agnostic. This approach should also not involve copying the video into other storage as it would simply expand the use of the users iCloud storage, providing a less than ideal user experience. If the user has opened the video from their Photos library, there should be a way to allow the same user (e.g. same Apple ID), to use the same app on another device to open the video again.
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1
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683
Activity
Nov ’25
Apple Music playlist create/delete works but DELETE returns 401 — and MusicKit write APIs are macOS‑unavailable. How to build a playlist editor on macOS?
I’m trying to build a playlist editor on macOS. I can create playlists via the Apple Music HTTP API, but DELETE always returns 401 even immediately after creation with the same tokens. Minimal repro: #!/usr/bin/env bash set -euo pipefail BASE_URL="https://api.music.apple.com/v1" PLAYLIST_NAME="${PLAYLIST_NAME:-blah}" : "${APPLE_MUSIC_DEV_TOKEN:?}" : "${APPLE_MUSIC_USER_TOKEN:?}" create_body="$(mktemp)" delete_body="$(mktemp)" trap 'rm -f "$create_body" "$delete_body"' EXIT curl -sS --compressed -o "$create_body" -w "Create status: %{http_code}\n" \ -X POST "${BASE_URL}/me/library/playlists" \ -H "Authorization: Bearer ${APPLE_MUSIC_DEV_TOKEN}" \ -H "Music-User-Token: ${APPLE_MUSIC_USER_TOKEN}" \ -H "Content-Type: application/json" \ -d "{\"attributes\":{\"name\":\"${PLAYLIST_NAME}\"}}" playlist_id="$(python3 - "$create_body" <<'PY' import json, sys with open(sys.argv[1], "r", encoding="utf-8") as f: data = json.load(f) print(data["data"][0]["id"]) PY )" curl -sS --compressed -o "$delete_body" -w "Delete status: %{http_code}\n" \ -X DELETE "${BASE_URL}/me/library/playlists/${playlist_id}" \ -H "Authorization: Bearer ${APPLE_MUSIC_DEV_TOKEN}" \ -H "Music-User-Token: ${APPLE_MUSIC_USER_TOKEN}" \ -H "Content-Type: application/json" I capture the response bodies like this: cat "$create_body" cat "$delete_body" Result: Create: 201 Delete: 401 I also checked the latest macOS SDK’s MusicKit interfaces and MusicLibrary.createPlaylist/edit/add(to:) are marked @available(macOS, unavailable), so I can’t create/ delete via MusicKit on macOS either. Question: How can I implement a playlist editor on macOS (create/delete/modify) if: MusicKit write APIs are unavailable on macOS, and The HTTP API can create but DELETE returns 401? Any guidance or official workaround would be hugely appreciated.
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316
Activity
Jan ’26
Indicate Packet Loss With AVAudioConverter for OPUS Decoding
I'm using an AVAudioConverter object to decode an OPUS stream for VoIP. The decoding itself works well, however, whenever the stream stalls (no more audio packet is available to decode because of network instability) this can be heard in crackling / abrupt stop in decoded audio. OPUS can mitigate this by indicating packet loss by passing a null pointer in the C-library to int opus_decode_float (OpusDecoder * st, const unsigned char * data, opus_int32 len, float * pcm, int frame_size, int decode_fec), see https://opus-codec.org/docs/opus_api-1.2/group__opus__decoder.html#ga9c554b8c0214e24733a299fe53bb3bd2. However, with AVAudioConverter using Swift I'm constructing an AVAudioCompressedBuffer like so:         let compressedBuffer = AVAudioCompressedBuffer(             format: VoiceEncoder.Constants.networkFormat,             packetCapacity: 1,             maximumPacketSize: data.count         )         compressedBuffer.byteLength = UInt32(data.count)         compressedBuffer.packetCount = 1   compressedBuffer.packetDescriptions! .pointee.mDataByteSize = UInt32(data.count)         data.copyBytes(             to: compressedBuffer.data .assumingMemoryBound(to: UInt8.self),             count: data.count         ) where data: Data contains the raw OPUS frame to be decoded. How can I specify data loss in this context and cause the AVAudioConverter to output PCM data whenever no more input data is available? More context: I'm specifying the audio format like this:         static let frameSize: UInt32 = 960         static let sampleRate: Float64 = 48000.0         static var networkFormatStreamDescription = AudioStreamBasicDescription(             mSampleRate: sampleRate,             mFormatID: kAudioFormatOpus,             mFormatFlags: 0,             mBytesPerPacket: 0,             mFramesPerPacket: frameSize,             mBytesPerFrame: 0,             mChannelsPerFrame: 1,             mBitsPerChannel: 0,             mReserved: 0         )         static let networkFormat = AVAudioFormat( streamDescription: &networkFormatStreamDescription )! I've tried 1) setting byteLength and packetCount to zero and 2) returning nil but setting .haveData in the AVAudioConverterInputBlock I'm using with no success.
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924
Activity
May ’25