Streaming

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Deep dive into the technical specifications that influence seamless playback for streaming services, including bitrates, codecs, and caching mechanisms.

Streaming Documentation

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AVPlayer periodic time observer stops notifying when switching back from AirPlay to local playback
The app registers a periodic time observer to the AVPlayer when the playback starts and it works fine. When switching to AirPlay during playback, the periodic time observation continues working as expected. However, when switching back to local playback, the periodic time observer does not fire anymore until a seek is performed. The app removes the periodic time observer only when the playback stops. I can see that when switching back to local playback, the timeControlStatus successively changes to .waitingToPlayAtSpecifiedRate (reason: .evaluatingBufferingRate) then to .waitingToPlayAtSpecifiedRate (reason: .toMinimizeStalls) and finally to .playing But the time observation does not work anymore. Also, the issue is systematic with Live and VOD streams providing a program date (with HLS property #EXT-X-PROGRAM-DATE-TIME), with or without any DRM, and is never reproduced with other VOD streams.
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Apr ’25
Issues with "AVMetricEventStreamPublisher Discover Media Performance Metrics in AVFoundation" Example Code
Hi everyone! I’ve been working with AVFoundation and trying to use the AVMetricEventStreamPublisher to discover media performance metrics, as described in the Apple documentation. https://developer.apple.com/cn/videos/play/wwdc2024/10113/?time=508 However, when following the example code, I’m not getting the expected results. The performance metrics for both audio and video don’t seem to be captured properly. Has anyone successfully used this example code? If so, could you share your experience or any solutions you’ve found? Any tips or insights would be greatly appreciated. Thanks in advance! Ps. the example code: AVPlayerItem *item = ... AVMetricEventStream *eventStream = [AVMetricEventStream eventStream]; id subscriber = [[MyMetricSubscriber alloc] init]; [eventStream setSubscriber:subscriber queue:mySerialQueue] [eventStream subscribeToMetricEvent:[AVMetricPlayerItemLikelyToKeepUpEvent class]]; [eventStream subscribeToMetricEvent:[AVMetricPlayerItemPlaybackSummaryEvent class]]; [eventStream addPublisher:item];
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CoreMediaErrorDomain -12888: Bandwidth down-stepping when using 2sec segment duration
the problem is when using HLS live stream with AVPlayer on iOS/ tvOS the player chooses first highest bandwidth then slowly steps down to lowest (within 1-3min) and eventually steps up again then repeats to step down. the AVPlayer error log sends events: errorStatusCode: -12888, errorDomain: Optional("CoreMediaErrorDomain"), errorComment: Optional("The operation couldn't be completed. (CoreMediaErrorDomain error -12888 - Playlist File unchanged for longer than 1.5 * target duration we use standard segments in CMAF format, 2sec duration #EXTM3U #EXT-X-VERSION:6 #EXT-X-TARGETDURATION:2 #EXT-X-MEDIA-SEQUENCE:147065903 #EXT-X-MAP:URI="video_1_4660000_init.mp4?device_profile=cmaf_cbcs_verimatrix_cei%26seg_size=2%26cmaf=2" #EXT-X-PROGRAM-DATE-TIME:2025-04-30T12:51:07 #EXTINF:2.000, video_1_4660000_t17460174670001555.mp4?device_profile=cmaf_cbcs_verimatrix_cei%26seg_size=2%26cmaf=2 #EXTINF:2.000, video_1_4660000_t17460174690001555.mp4?device_profile=cmaf_cbcs_verimatrix_cei%26seg_size=2%26cmaf=2 #EXTINF:2.000, video_1_4660000_t17460174710001555.mp4?device_profile=cmaf_cbcs_verimatrix_cei%26seg_size=2%26cmaf=2 when using 6sec segments the player stays stable at highest bandwidth. is there a way to avoid this error? in AVPlayer or HLS configuration?
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218
May ’25
Race issue - Custom AVAssetResourceLoaderDelegate cannot work with EXT-X-SESSION-KEY
TL;DR How to solve possible racing issue of EXT-X-SESSION-KEY request and encrypted media segment request? I'm having trouble using custom AVAssetResourceLoaderDelegate with video manifest containing VideoProtectionKey(VPK). My master manifest contains rendition manifest url and VPK url. When not using custom resource delegate, everything works fine. My custom resource delegate is implemented in way where it first append prefix to scheme of the master manifest url before creating the asset. And during handling master manifest, it puts back original scheme, make the request, modify the scheme for rendition manifest url in the response content by appending the same prefix again, so that rendition manifest request also goes into custom resource loader delegate. Same goes for VPK request. The AES-128 key is stored in memory within custom resource loader delegate object. So far so good. The VPK is requested before segment request. But the problem comes where the media segment requests happen. The media segment request url from rendition manifest goes into custom resource loader as well and those are encrypted. I can see segment request finish first then the related VPK requests kick in after a few seconds. The previous VPK value is cached in memory so it is not network causing the delay but some mechanism that I'm not aware of causing this. So could anyone tell me what would be the proper way of handling this situation? The native library is handling it well so I just want to know how. Thanks in advance!
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Jun ’25
Will the new Automix feature in iOS 26 be available for third-party apps using MusicKit?
Hi everyone, We’re currently developing a music-based app using MusicKit, and we recently noticed that iOS 26 beta introduces a new “Automix” feature in the Apple Music app. This enables seamless DJ-style transitions between songs—beyond the standard crossfade functionality. We’re trying to understand: Will this Automix feature be accessible to third-party apps that use MusicKit? If not available in the initial iOS 26 release, is there a plan to expose it through public APIs in a future update? Is there any technical documentation, WWDC session, or roadmap info regarding Automix support via MusicKit? This functionality would be a significant enhancement for our app, especially for intelligent audio transitions and curated playlists. Thanks.
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Apple Music Artist - genres
The documentation for the Apple Music API indicates that the genreNames field for a given artist (see https://developer.apple.com/documentation/applemusicapi/artists/attributes-data.dictionary) is an array of strings. However, it only appears as though you return ONE SINGLE GENRE per Artist, regardless of how many genres might be attached to that artist's albums. Am I missing something? Is there an artist where multiple genres may be returned, or is this a bug in the documentation?
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518
Jul ’25
Questions about H.264 encoding settings with low-latency rate control
Hi everyone, I noticed that Apple recently added a few new beta sample codes related to video encoding: Encoding video for low-latency conferencing Encoding video for live streaming While experimenting with H.264 encoding, I came across some questions regarding certain configurations: When I enable kVTVideoEncoderSpecification_EnableLowLatencyRateControl, is it still possible to use kVTCompressionPropertyKey_VariableBitRate? In my tests, I get an error. It also seems that kVTVideoEncoderSpecification_EnableLowLatencyRateControl cannot be used together with kVTCompressionPropertyKey_ConstantBitRate when encoding H264. Is that expected? When using kVTCompressionPropertyKey_ConstantBitRate with kVTCompressionPropertyKey_MaxKeyFrameInterval set to 2, the encoder outputs only keyframes, and the frame size keeps increasing, which doesn’t seem like the intended behavior. Regarding the following code from the sample: let byteLimit = (Double(bitrate) / 8) * 1.5 as CFNumber let secLimit = Double(1.0) as CFNumber let limitsArray = [ byteLimit, secLimit ] as CFArray // Each 1 second limit byte as bitrate err = VTSessionSetProperty(session, key: kVTCompressionPropertyKey_DataRateLimits, value: limitsArray) This DataRateLimits setting doesn’t seem to have any effect in my tests. Whether I set it or not, the values remain unchanged. Since the documentation on developer.apple.com/documentation doesn’t clearly explain these cases, I’d like to ask if anyone has insights or recommendations about the proper usage of these settings. Thanks in advance!
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491
Sep ’25
CoreMediaErrorDomain -15628 playback failure in iOS 26 (React Native / AVPlayer, HLS stream)
Hi, After updating to iOS 26, our app is facing playback failures with AVPlayer. The same code and streams work fine on iOS 18 and earlier. Error - Domain[CoreMediaErrorDomain]:Code[-15628]:Desc[The operation couldn’t be completed.]:Underlying Error Domain[(null)]:Code[0]:Desc[(null)] Environment: iOS version: ios 26 React Native: 0.69 Video library: react-native-video (AVPlayer under the hood) Stream type: HLS (m3u8) with segment (.ts) files Observed behaviour: Playback works initially on iOS 26. On iOS 26, the stream fails at runtime after a few seconds/minutes (not on first load). Network logs show 307 redirects on some segment requests. After this, AVPlayer throws the above error. Playback fails intermittently on slow/unstable networks.
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2w
AVPlayer HLS High Bitrate Problem on Apple TV HD (A1625) tvOS 26
Hello, We have Video Stream app. It has HLS VOD Content. We supply 1080p, 4K Contents to users. Users were watching 1080p content before tvOS 26. Users can not watch 1080p content anymore when they update to tvOS 26. We have not changed anything at HLS playlist side and application version. This problem only occurs on Apple TV 4th Gen (A1625) tvOS 26 version. There is no problem with newer Apple TV devices. Would you help to resolve problem? Thanks in advance
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2w
Feature / Workaround wanted: Seamless, Automated AirPlay Screen Streaming on visionOS for Demos
Hello Apple team and developer community, I am preparing a visionOS app for a fair environment, where we want to automatically stream the current experience to a nearby monitor via AirPlay, without requiring guests or staff to manually interact with the Control Center or AirPlay pickers all the time. The goal is to provide a smooth, frictionless setup so attendees can focus on the demo, not the configuration. Feature Request: A supported API or method to programmatically start/stop AirPlay video streaming (mirroring or external playback) from within a visionOS app, allowing the current experience to be instantly displayed on an external monitor or Apple TV for the audience. Context & Rationale: In a trade fair or exhibition setting, rapid guest turnaround and minimal staff intervention are crucial. Having to manually guide each visitor through AirPlay setup is impractical. As I understood, AVRoutePickerView can be used for this on iOS/macOS, but this is not available in visionOS. Enabling similar automated streaming on visionOS would make the device far more suitable for live demos and public showcases. Questions: Are there any supported workarounds or best practices for enabling automated screen streaming or AirPlay initiation on visionOS in public demo environments that I missed? Is Apple considering adding programmatic AirPlay control or accessibility features to support such use cases in future visionOS releases? Thank you for considering this request! If there are recommended patterns, entitlements, or accessibility solutions we could explore for trade fair scenarios, your guidance would be greatly appreciated. Best regards, Julian Zürn - IPI, HS Kempten
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1w
Multiview HLS with HDR
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?
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1k
Feb ’25
I cannot revoke Apple Fairplay Streaming certificate
We move to another streaming service and need to deliver a ASK, .PEM &key, and CRT to enable DRM. Now the issue is that we don't have that information anymore. Most logical would be to revoke the current certificate and create a new one. Unfortunately for Fairplay Streaming Certificates there is no revoke button. We asked developer support who isn't able to help. We then did a request to revoke as described in article 2.7 of the Apple Developer Program License Agreement. They can only do this when the certificate is compromised. So now we are stuck. Anyone out there who had the same issue and found a solution? Your help is much appreciated.
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624
Jan ’25
SCStreamDelegetate stream:didStopWithError receiving null pointer for error
I have an SCStreamDelegate for capturing frames from applications. On recent point releases of macOS Sonoma, I've noticed that the stream is being cancelled with no user action being taken. I started trying to debug it and when my on error method is called, the error parameter being passed is null: func stream(_ stream: SCStream, didStopWithError error: Error) { /*debugger shows this and segfaults if I try to print "\(error)" error (Error) > error = (Builtin.RawPointer) 0x0 */ From what I can tell, error should be a valid NSError so I can check the error code, based on similar code I've seen in, for example OBS (https://github.com/obsproject/obs-studio/blob/265239d4174f8d291b0de437088c5b78f8e27687/plugins/mac-capture/mac-sck-common.m#L29) Usually when this happens, the menubar icon for screen sharing (where I would click to change sharing window, etc) stays there even after my app has closed an no apps are doing sharing stuff. Has anyone come across this before? Am I misinterpreting what the debugger is saying about the error parameter? I'm running macos 14.7.3, but I just updated from 14.7.2 earlier and had basically the same issue on both macos versions
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Mar ’25
Playback Issues for DRM content when sending CMCD
Since iOS and tvOS 18, CMCD can now be automatically sent by AVPlayer (https://developer.apple.com/streaming/Whats-new-HLS.pdf). However, after enabling CMCD, our streams occasionally fail with the following error: CoreMediaErrorDomain Error -17383 This issue appears to affect only DRM-protected (FairPlay) streams so far. We activate CMCD via the resource loader of an AVURLAsset, before assigning the item to an AVPlayer. Unfortunately, we haven’t found a reliable way to reproduce the issue, and we’ve been unable to gather any useful diagnostic information. Has anyone else observed this behavior when enabling CMCD on FairPlay streams?
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4w
Email "Updates to FairPlay Streaming Server SDK" makes no sense
Hi, While I don't normally use FairPlay, I got this email that is so strangely worded I am wondering if it makes sense to people who do know it or if it has some typo or what. You can only generate certificates for SDK 4, also SDK 4 is no longer supported? (Also "will not expire" is imprecise phrasing, certificates presumably will expire, I think it meant to say are still valid / are not invalidated.)
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3w
TV A1625 Using 3× More CPU After tvOS 26 Update
Hi everyone, After updating my Apple TV HD (model A1625) to tvOS 26, I’ve noticed a significant spike in CPU usage—up to 3× higher than before the update. Go from around 40% to 120% Model: Apple TV HD (A1625) tvOS Version: 26 (stable release) and beta version of 26.1, App downgrade stream due to lack of cpu power If anyone else is experiencing this, please share your findings or workarounds. Would love to hear from Apple engineers or other developers if this is a known regression or if there’s a recommended fix. Thanks!
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Oct ’25
How to consume video from an RTSP service?
Hi,It seems like it's pretty easy to consume HTTP Live Streaming content in an iOS app. Unfortunately, I need to consume media from an RTSP server. It seems to me that this is a very similar thing, and that all of the underpinnings for doing it ought to be present in iOS, but I'm having a devil of a time figuring out how to make it work without doing a lot of programming.For starters, I know that there are web-based services that can consume an RTSP stream and rebroadcast it as an HTTP Live Stream that can be easily consumed by the media players in iOS. This won't work for me because my application needs to function in an environment where there is no internet access (it's on a private Wifi network where the only other thing on the network is the device that is serving the RTSP stream).Having read everything I can get my hands on and exploring third-party and open-source solutions, I've compiled the following list of ideas:1. Using an iOS build of the open-source ffmpeg library, which supports RTSP, I've come up with a test app that can receive the RTSP packets, decode them, create UIImages out of the frames, and display those frames on-screen. This provides a crude player, but performance is poor, most likely because ffmpeg can't take advantage of any hardware acceleration. It also doesn't provide me with any way to integrate the video stream into AVFoundation, so I'm on my own as far as saving the stream to a file, transcoding it, etc.2. I know that the AVURLAsset class doesn't directly support the RTSP scheme. Since I have access to the undecoded RTSP packets via ffmpeg, I've thought it should be possible to implement RTSP support myself via a custom NSURLProtocol, essentially fooling AVFoundation into reading those packets as if they originated in a file. I'm not sure if this would work, since the raw packets coming from the RTSP server might lack the headers that would otherwise be present in data being read from a file. I'm not even sure if AVFoundation would recognize my custom protocol.3. If a protocol doesn't work, I've considered that I might be able to implement my own local HTTP Live Streaming server that converts the RTSP packets into an HTTP stream that the media players can read. This sounds like a terribly convoluted solution to the problem, at best, and very difficult at worst.4. Going back to solution (1), if I could speed up the decoding by using some iOS CoreVideo function instead of ffmpeg, this solution might be okay. However, I can't find any documentation for CoreVideo on iOS (Apple only documents it for OS X).5. I'm certainly willing to license a third-party solution if it works well and provides good performance. Unfortunately, everything I've found so far is pretty crummy and mostly just leverages ffmpeg and/or VLC. What is most disappointing to me is that nobody seems to be able or willing to provide a solution that neatly integrates with AVFoundation. I really want to make my RTSP stream available as an AVAsset so I can use it with AVFoundation players and other classes -- I don't want to build an app that relies on custom third-party code for everything.Any ideas, tips, advice would be greatly appreciated.Thanks,Frank
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Oct ’25
AV Player Live playback Pause is not working on tvOS 18
In our Apple TV application, we use the native AVPlayer for live playback functionality. Until tvOS 17.6 and during the tvOS 18 beta, the Pause/Resume feature worked as expected, allowing us to pause live playback. However, after updating to tvOS 18.1, the pause functionality no longer works. The same app still works fine on tvOS 17, but on tvOS 18, attempting to pause live playback has no effect. We reviewed the tvOS 18 release notes but couldn't find any relevant changes or deprecations related to AVPlayer or live playback behavior. Has there been any change in the handling of live playback or the Pause/Resume functionality in tvOS 18.1? Any guidance or suggestions to address this issue would be greatly appreciated. Thank you!
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Feb ’25