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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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FairPlay Client Question
The ASk is used by the KSM to derive the dASk, which is then used to decrypt the SK...R1. If the only thing we give the client is the certificate, how does it encrypt the SK...R1 so the server is able to process it. Would be nice to know it it works generally, because I've been getting questions about it and can't provide a helpful answer. Thanks in advance.
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202
Jan ’26
Inquiry about Low-Latency Frame Interpolation & Super Resolution using VTFrameProcessor
Hello, I have implemented Low-Latency Frame Interpolation using the VTFrameProcessor framework, based on the sample code from https://aninterestingwebsite.com/kr/videos/play/wwdc2025/300. It is currently working well for both LIVE and VOD streams. However, I have a few questions regarding the lifecycle management and synchronization of this feature: 1. Common Questions (Applicable to both Frame Interpolation & Super Resolution) 1.1 Dynamic Toggling Do you recommend enabling/disabling these features dynamically during playback? Or is it better practice to configure them only during the initial setup/preparation phase? If dynamic toggling is supported, are there any recommended patterns for managing VTFrameProcessor session lifecycle (e.g., startSession / endSession timing)? 1.2 Synchronization Method I am currently using CADisplayLink to fetch frames from AVPlayerItemVideoOutput and perform processing. Is CADisplayLink the recommended approach for real-time frame acquisition with VTFrameProcessor? If the feature needs to be toggled on/off during active playback, are there any concerns or alternative approaches you would recommend? 1.3 Supported Resolution/Quality Range What are the minimum and maximum video resolutions supported for each feature? Are there any aspect ratio restrictions (e.g., does it support 1:1 square videos)? Is there a recommended resolution range for optimal performance and quality? 2. Frame Interpolation Specific Questions 2.1 LIVE Stream Support Is Low-Latency Frame Interpolation suitable for LIVE streaming scenarios where latency is critical? Are there any special considerations for LIVE vs VOD? 3. Super Resolution Specific Questions 3.1 Adaptive Bitrate (ABR) Stream Support In ABR (HLS/DASH) streams, the video resolution can change dynamically during playback. Is VTLowLatencySuperResolutionScaler compatible with ABR streams where resolution changes mid-playback? If resolution changes occur, should I recreate the VTLowLatencySuperResolutionScalerConfiguration and restart the session, or does the API handle this automatically? 3.2 Small/Square Resolution Issue I observed that 144x144 (1:1 square) videos fail with error:   "VTFrameProcessorErrorDomain Code=-19730: processWithSourceFrame within VCPFrameSuperResolutionProcessor failed" However, 480x270 (16:9) videos work correctly. minimumDimensions reports 96x96, but 144x144 still fails. Is there an undocumented restriction on aspect ratio or a practical minimum resolution? 3.3 Scale Factor Selection supportedScaleFactors returns [2.0, 4.0] for most resolutions. Is there a recommended scale factor for balancing quality and performance? Are there scenarios where 4.0x should be avoided? The documentation on this specific topic seems limited, so I would appreciate any insights or advice. Thank you.
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448
Feb ’26
A mistake in FairPlay Streaming SDK 26 sample code on comparing ProtocolVersionUsed value?
Hello, I am reviewing the sample codes of FairPlay Streaming SDK 26 and there was a place where I think is a mistake. The codes are for the server, for both Swift and Rust codes. There is an if statement which compares "ProtocolVersionUsed"(spcData.versionUsed) and SPCVersion1 constant, though "ProtocolVersionUsed" and SPC Version is a different thing, so shouldn't it be using a different constant value? [createContentKeyPayload.swift] // Fallback to version 1 if content can have encrypted slice headers, which need to be decrypted separately. Slice headers are not encrypted when using CBCS. if serverCtx.spcContainer.spcData.versionUsed == base_constants.SPCVersion.v1.rawValue && [createContentKeyPayload.rs] // Fallback to version 1 if content can have encrypted slice headers, which need to be decrypted separately. Slice headers are not encrypted when using CBCS. if (serverCtx.spcContainer.spcData.versionUsed == SPCVersion::v1 as u32) && Thank you.
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104
Feb ’26
The audio of FairPlay protected content can be captured - Safari on iOS
Hi, Has anyone been able to protect the audio part of FairPlay protected content from being captured as part of screen recording on Safari/iOS (PWA and/or online web app)? We have tried many things but could not prevent the audio from being recorded. Same app and content on Safari/Mac does not allow audio to be recorded. Any tips?
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1w
Unity iOS (Metal) → WebRTC (Unity WebRTC) video stream to remote Unity client: PeerConnection connects but receiver renders black frames
Hello! My name is Mason Prather. I'm a graduate student at Kennesaw State University and a Research Engineer working in XR environments through my Graduate Research Assistant role. I’m currently building a research prototype that connects a mobile companion application to a VR headset. The mobile application is built in Unity and deployed on iOS, and it streams video frames to a remote Unity client using WebRTC. Environment Device: iPhone 15 OS: iOS 26.3 (tested on physical device, not Simulator) Engine: Unity 2022.3.57f1 Graphics API: Metal Streaming Technology: WebRTC (Unity WebRTC package) Architecture: Mobile Unity app streaming video frames to a remote Unity client Receiver Device: Meta Quest Pro headset (Unity application) Networking: LAN (UDP discovery + TCP signaling) Video Source: Unity RenderTexture Goal The goal of the system is to allow a VR user to view media stored on their phone inside a VR environment. The iOS app: renders or captures media content converts frames into a WebRTC video track streams the video to the headset Current Status Connection setup works correctly. Observed behavior: Signaling connection successful ICE candidate exchange successful PeerConnection state becomes Connected Video track created successfully However, the receiving application displays black frames. iOS App Details The video source originates from a Unity RenderTexture. Inside the phone application: RenderTexture displays correctly Frames appear correct locally But the receiving peer does not display the frames. Relevant Components Unity WebRTC package iOS Metal rendering pipeline Custom TCP signaling LAN discovery via UDP Expected Behavior Rendered frames should transmit via WebRTC and appear on the remote device. Actual Behavior The remote video track is active, but the rendered frames appear black on the receiving client. Questions Are there known issues involving Unity WebRTC + iOS Metal texture capture? Are there specific pixel format requirements when streaming textures from Unity on iOS? Could the issue relate to texture readback limitations or GPU synchronization? I am more than happy to provide screenshots and console logs upon request. If anyone has experience streaming Unity video frames via WebRTC on iOS, I would greatly appreciate any guidance.
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218
Mar ’26
On iOS 26, HLS alternate audio track selection behaves inconsistently
Summary On iOS 26, HLS alternate audio track selection behaves inconsistently on both VOD and live streams: the French track falls back to the DEFAULT=YES (English) track after manual selection, and in some cases switching to a non-default track appears to work but it is then impossible to switch back to English. Environment iOS version: 26 Players affected: native Safari on iOS 26 and THEOplayer (issue also reproducible on THEOplayer's own demo page) Stream type: HLS/CMAF with demuxed alternate audio renditions (CMFC container) Affected stream types: both VOD and live streaming Issue NOT present on iOS 17/18 Manifest #EXTM3U #EXT-X-VERSION:4 #EXT-X-INDEPENDENT-SEGMENTS #EXT-X-STREAM-INF:BANDWIDTH=8987973,AVERAGE-BANDWIDTH=8987973,VIDEO-RANGE=SDR,CODECS="avc1.640028",RESOLUTION=1920x1080,FRAME-RATE=29.970,AUDIO="program_audio" video_1080p.m3u8 #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="program_audio",LANGUAGE="en",ASSOC-LANGUAGE="en",NAME="English",AUTOSELECT=YES,DEFAULT=YES,CHANNELS="2",URI="audio_ENG.m3u8" #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="program_audio",LANGUAGE="de",ASSOC-LANGUAGE="de",NAME="Deutsch",AUTOSELECT=YES,DEFAULT=NO,CHANNELS="2",URI="audio_DEU.m3u8" #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="program_audio",LANGUAGE="fr",ASSOC-LANGUAGE="fr",NAME="Francais",AUTOSELECT=YES,DEFAULT=NO,CHANNELS="2",URI="audio_FRA.m3u8" Steps to Reproduce Load the HLS manifest (VOD or live) in Safari on iOS 26, or in any AVFoundation-backed player Start playback — English plays correctly as DEFAULT Manually select "Francais" from the audio track selector Observe that English audio continues playing (French does not play) In a separate scenario: manually select "Deutsch" — German plays correctly Attempt to switch back to English — English does not resume; audio remains on the previously selected track Expected behavior Selecting any track should immediately switch to that language Switching back to English (DEFAULT=YES) should work at any time Behavior should be consistent across VOD and live streams Actual behavior Two distinct anomalies observed, reproducible on both VOD and live streams, in both native Safari and THEOplayer: French-specific fallback: selecting the French track causes playback to fall back to English. This does not happen with German. Cannot return to English: in cases where a non-default track plays correctly, attempting to switch back to the DEFAULT=YES track (English) fails — the previous non-default track continues playing. The fact that the issue reproduces in native Safari confirms this is an AVFoundation/WebKit-level regression, not a third-party player bug. What we have already verified and ruled out LANGUAGE codes are BCP-47 compliant (en, fr, de) ✓ EXT-X-VERSION:4 is present ✓ Audio codec removed from STREAM-INF CODECS (video-only) ✓ ASSOC-LANGUAGE attribute added matching LANGUAGE value ✓ Container metadata verified via ffprobe: mdhd box correctly contains language tags (e.g. "fra") ✓ Audio segment content verified via ffplay: correct audio in each language file ✓ French audio source file contains correct French audio content ✓ Issue reproduces in native Safari on iOS 26, confirming it is not a THEOplayer-specific bug Issue does NOT reproduce on iOS 17/18 with the same manifest and segments Additional notes The VOD stream is packaged with AWS MediaConvert, CMAF output group, SEGMENTED_FILES, AAC-LC codec (mp4a.40.2), 128kbps, 48kHz stereo. English uses AudioTrackType ALTERNATE_AUDIO_AUTO_SELECT_DEFAULT; French and German use ALTERNATE_AUDIO_AUTO_SELECT. The live stream uses AWS MediaPackage with a similar CMAF/HLS output configuration. Please advise whether this is a known regression in AVFoundation on iOS 26 and whether a fix is planned.
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Generating a new FPS certificate (SDK 26) alongside an existing SDK 4 certificate
Hi, Our client currently has an FPS deployment certificate generated with SDK version 4 that is still actively used in production. They would like to generate an additional certificate using SDK version 26. Before doing so, they just want to confirm: Will the existing SDK 4 certificate remain unaffected and still visible in the Apple Developer portal? Any considerations they should keep in mind? Thanks! :)
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Generating a new FPS certificate (SDK 26) alongside an existing SDK 4 certificate
Hi, Our client currently has an FPS deployment certificate generated with SDK version 4 that is still actively used in production. They would like to generate an additional certificate using SDK version 26. Before doing so, they just want to confirm: Will the existing SDK 4 certificate remain unaffected and still visible in the Apple Developer portal? Any considerations they should keep in mind? Thanks!
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Technical guidance request: native screen capture protection on macOS with Flutter while allowing AirPlay
Hello Apple Developer Support, I am reaching out for technical guidance regarding screen capture protection behavior on macOS. We are building a desktop application using Flutter running on macOS, and we have implemented native Swift code inside the macOS Runner in order to protect sensitive content from screen recording and screen sharing. Our current implementation relies on native window-level protection and display state handling from Swift, while the main UI remains rendered by Flutter. The main challenge we are facing is the following: we need to keep a strong native anti-recording protection on macOS the application is heavily used with AirPlay and screen mirroring currently, AirPlay / mirroring is often interpreted by the system similarly to screen capture or screen recording this causes our protected content to be replaced by a gray or blank area even during legitimate AirPlay usage In practice, we would like to allow: AirPlay legitimate external display / mirroring usage while still preventing: screen recording screen sharing unauthorized screen capture We would like to know whether Apple recommends an official supported approach for this use case, preferably using public APIs. More specifically: Is there an officially supported way on macOS to distinguish AirPlay mirroring from screen recording / screen sharing? Is "NSWindow.sharingType" the recommended public API for this scenario? Is there a recommended approach when the UI surface is rendered through Flutter / Metal? Are there any best practices with ScreenCaptureKit for protecting content without affecting AirPlay? We understand that some lower-level APIs may not be officially supported, so we would greatly appreciate guidance toward a public and future-proof implementation path. Thank you very much for your time and support. Best regards, Tony
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Playback Issues for DRM content when sending CMCD
Since iOS and tvOS 18, CMCD can now be automatically sent by AVPlayer (https://aninterestingwebsite.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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584
Oct ’25
AVAssetWriterInputTaggedPixelBufferGroupAdaptor Hanging With Tagged Buffers
We've successfully implemented an AVAssetWriter to produce HLS streams (all code is Objective-C++ for interop with existing codebase) but are struggling to extend the operations to use tagged buffers. We're starting to wonder if the tagged buffers required for an MV-HEVC signal are fully supported when producing HLS segments in a live-stream setting. We generate a live stream of data using something like: UTType *t = [UTType typeWithIdentifier:AVFileTypeMPEG4]; m_writter = [[AVAssetWriter alloc] initWithContentType:t]; // - videoHint describes HEVC and width/height // - m_videoConfig includes compression settings and, when using MV-HEVC, // the correct keys are added (i.e. kVTCompressionPropertyKey_MVHEVCVideoLayerIDs) // The app was throwing an exception without these which was // useful to know when we got the configuration right. m_video = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo outputSettings:m_videoConfig sourceFormatHint:videoHint]; For either path we're producing CVPixelBufferRefs that contain the raw pixel information (i.e. 32BGRA) so we use an adapter to make that as simple as possible. If we use a single view and a AVAssetWriterInputPixelBufferAdaptor things work out very well. We produce segments and the delegate is called. However, if we use the AVAssetWriterInputTaggedPixelBufferGroupAdaptor as exampled in the SideBySideToMVHEVC demo project, things go poorly. We create the tagged buffers with something like: CMTagCollectionRef collections[2]; CMTag leftTags[] = { CMTagMakeWithSInt64Value( kCMTagCategory_VideoLayerID, (int64_t)0), CMTagMakeWithSInt64Value( kCMTagCategory_StereoView, kCMStereoView_LeftEye) }; CMTagCollectionCreate( kCFAllocatorDefault, leftTags, 2, &(collections[0]) ); CMTag rightTags[] = { CMTagMakeWithSInt64Value( kCMTagCategory_VideoLayerID, (int64_t)1), CMTagMakeWithSInt64Value( kCMTagCategory_StereoView, kCMStereoView_RightEye) }; CMTagCollectionCreate( kCFAllocatorDefault, rightTags, 2, &(collections[1]) ); CFArrayRef tagCollections = CFArrayCreate( kCFAllocatorDefault, (const void **)collections, 2, &kCFTypeArrayCallBacks ); CVPixelBufferRef buffers[] = {*b, *alt}; CFArrayRef b = CFArrayCreate( kCFAllocatorDefault, (const void **)buffers, 2, &kCFTypeArrayCallBacks ); CMTaggedBufferGroupRef bufferGroup; OSStatus res = CMTaggedBufferGroupCreate( kCFAllocatorDefault, tagCollections, b, &bufferGroup ); Perhaps there's something about this OBJC code that I've buggered up? Hopefully! Anyways, when I submit this tagged bugger group to the adaptor: if (![mvVideoAdapter appendTaggedPixelBufferGroup:bufferGroup withPresentationTime:pts]) { // report error... } Appending does not raise any errors - eventually it just hangs on us and we never return from it... Real Issue: So either: The delegate assigned to the AVAssetWriter doesn't fire its assetWriter callback which should produce the segments The adapter hangs on the appendTaggedPixelBufferGroup before a segment is ready to be completed (but succeeds for a number of buffer groups before this happens). This is the same delegate class that's assigned to the non multi view code path if MV-HEVC is turned off which works perfectly.
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Apr ’25
FPS Certificate Re-issuance and Validity of Existing Certificate
Keywords: FairPlay, FPS Certificate, DRM, FairPlay Streaming, license server Hi all, We are currently using FairPlay Streaming in production and already have an FPS certificate in place. However, the passphrase for the existing FPS certificate has unfortunately been lost. We are now considering reissuing a new FPS certificate, and I would like to confirm a few points before proceeding: 1️⃣ If we reissue a new FPS certificate, will the existing certificate be automatically revoked? Or will it remain valid until its original expiration date? 2️⃣ Is it possible to have both the newly issued and the existing certificates valid at the same time? In other words, can we serve DRM licenses using either certificate depending on the packaging or client? 3️⃣ Are there any caveats or best practices we should be aware of when reissuing an FPS certificate? For example, would existing packaged content become unplayable, or would CDN/packaging server configurations need to be updated carefully? Since this affects our production environment, we would like to minimize any service disruption or compatibility issues. Unfortunately, when we contacted Apple support directly, we were advised to post this question here in the Forums for additional guidance. Any advice or experiences would be greatly appreciated! Thank you in advance.
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204
Jun ’25
Disconnect from AirPlay device programmatically
Hello there, I'm trying to implement feature which uses AirPlay with Apple TV. I want to disconnect from the device programmatically when something happens. Under something I mean a situation when a user wants to stop broadcasting (for example close the PiP window on his phone). I use this snippet: try audioSession.setCategory(.playAndRecord, options: .defaultToSpeaker) try audioSession.setActive(true, options: .notifyOthersOnDeactivation) It works fine sometimes but not always (it works on iOS 18 but it doesn't on iOS 17 or ). So I thought it's a bug and create a ticker to feedback assistant (FB21220013). The support told me write a post on the forum.
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Dec ’25
Cannot generate 2048-bit FairPlay Streaming certificate
Hello, I have a problem generating a 2048-bit FairPlay Streaming certificate. I tried generating SDK v26.x certificate in two ways. (1) Use existing certificate (2) Create new certificate Though, in both ways, Apple gives me a certificate bundle of 1024-bit certificate. (fps_certificate.bin) I've uploaded 2048-bit CSR on creating a certificate. Just to note, I have created a SDK v4.x certificate few years ago. Have anyone bumped into a same issue? Or am I missing something?
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Feb ’26
Crash when trying to get originatingRecipient
According to the documentation (https://aninterestingwebsite.com/documentation/avfoundation/avcontentkeyrequest/originatingrecipient?changes=_3&language=objc), starting with ios 18.4, I can get AVContentKeyRecipient from AVContentKeyRequest. But when I try to get it, I get a crash. What could be the issue? I want to note that I add the asset to the AVContentKeySession using the addContentKeyRecipient method (https://aninterestingwebsite.com/documentation/avfoundation/avcontentkeysession/addcontentkeyrecipient(_:)?changes=_3&language=objc).
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280
Feb ’26
Inquiry regarding CoreMediaErrorDomain Code=-15517 during LL-HLS Live Playback
Hello, I am currently developing a live streaming application using AVPlayer to play LL-HLS (Low-Latency HLS) content. During our testing phase, we consistently encountered the following error in the logs: CoreMediaErrorDomain Code=-15517 The challenge we are facing is that the error description is quite vague. It only provides cryptic messages such as "Key not found" or "No value information," which makes it extremely difficult to identify the root cause or perform a deep-dive analysis. I have searched through the official Apple Developer documentation and technical notes, but I couldn’t find any specific reference to what Code -15517 signifies in the context of LL-HLS or CoreMedia. Regarding this issue, I have the following questions: What is the specific meaning of this error code (-15517)? Does it relate to missing tags in the HLS manifest, or is it an internal state issue within the AVPlayer stack? 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. Is there any additional logging or debugging tool you would recommend to further investigate "Key not found" issues in LL-HLS? Any insights or guidance from the community or Apple engineers would be greatly appreciated. Thank you in advance for your help.
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Feb ’26
Offline Fairplay Error -42650
We have implemented offline Fairplay playback and it works fine.But at times when trying to playback the offline downloaded content, we get the following error"An unknown error occured (-42650)"Tried looking up the error in the documentation but couldnt find anything relevant.What could possibly be creating this error?
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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
Apple Vision Pro streaming spatial video transmission
I want develop an app for real-time streaming spatial video transmission from an Apple Vision Pro to another Apple Vision Pro and play, like MV-HEVC, does it's possible? If it's possible how to make it?
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141
Activity
Jan ’26
FairPlay Client Question
The ASk is used by the KSM to derive the dASk, which is then used to decrypt the SK...R1. If the only thing we give the client is the certificate, how does it encrypt the SK...R1 so the server is able to process it. Would be nice to know it it works generally, because I've been getting questions about it and can't provide a helpful answer. Thanks in advance.
Replies
1
Boosts
0
Views
202
Activity
Jan ’26
Inquiry about Low-Latency Frame Interpolation & Super Resolution using VTFrameProcessor
Hello, I have implemented Low-Latency Frame Interpolation using the VTFrameProcessor framework, based on the sample code from https://aninterestingwebsite.com/kr/videos/play/wwdc2025/300. It is currently working well for both LIVE and VOD streams. However, I have a few questions regarding the lifecycle management and synchronization of this feature: 1. Common Questions (Applicable to both Frame Interpolation & Super Resolution) 1.1 Dynamic Toggling Do you recommend enabling/disabling these features dynamically during playback? Or is it better practice to configure them only during the initial setup/preparation phase? If dynamic toggling is supported, are there any recommended patterns for managing VTFrameProcessor session lifecycle (e.g., startSession / endSession timing)? 1.2 Synchronization Method I am currently using CADisplayLink to fetch frames from AVPlayerItemVideoOutput and perform processing. Is CADisplayLink the recommended approach for real-time frame acquisition with VTFrameProcessor? If the feature needs to be toggled on/off during active playback, are there any concerns or alternative approaches you would recommend? 1.3 Supported Resolution/Quality Range What are the minimum and maximum video resolutions supported for each feature? Are there any aspect ratio restrictions (e.g., does it support 1:1 square videos)? Is there a recommended resolution range for optimal performance and quality? 2. Frame Interpolation Specific Questions 2.1 LIVE Stream Support Is Low-Latency Frame Interpolation suitable for LIVE streaming scenarios where latency is critical? Are there any special considerations for LIVE vs VOD? 3. Super Resolution Specific Questions 3.1 Adaptive Bitrate (ABR) Stream Support In ABR (HLS/DASH) streams, the video resolution can change dynamically during playback. Is VTLowLatencySuperResolutionScaler compatible with ABR streams where resolution changes mid-playback? If resolution changes occur, should I recreate the VTLowLatencySuperResolutionScalerConfiguration and restart the session, or does the API handle this automatically? 3.2 Small/Square Resolution Issue I observed that 144x144 (1:1 square) videos fail with error:   "VTFrameProcessorErrorDomain Code=-19730: processWithSourceFrame within VCPFrameSuperResolutionProcessor failed" However, 480x270 (16:9) videos work correctly. minimumDimensions reports 96x96, but 144x144 still fails. Is there an undocumented restriction on aspect ratio or a practical minimum resolution? 3.3 Scale Factor Selection supportedScaleFactors returns [2.0, 4.0] for most resolutions. Is there a recommended scale factor for balancing quality and performance? Are there scenarios where 4.0x should be avoided? The documentation on this specific topic seems limited, so I would appreciate any insights or advice. Thank you.
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0
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448
Activity
Feb ’26
A mistake in FairPlay Streaming SDK 26 sample code on comparing ProtocolVersionUsed value?
Hello, I am reviewing the sample codes of FairPlay Streaming SDK 26 and there was a place where I think is a mistake. The codes are for the server, for both Swift and Rust codes. There is an if statement which compares "ProtocolVersionUsed"(spcData.versionUsed) and SPCVersion1 constant, though "ProtocolVersionUsed" and SPC Version is a different thing, so shouldn't it be using a different constant value? [createContentKeyPayload.swift] // Fallback to version 1 if content can have encrypted slice headers, which need to be decrypted separately. Slice headers are not encrypted when using CBCS. if serverCtx.spcContainer.spcData.versionUsed == base_constants.SPCVersion.v1.rawValue && [createContentKeyPayload.rs] // Fallback to version 1 if content can have encrypted slice headers, which need to be decrypted separately. Slice headers are not encrypted when using CBCS. if (serverCtx.spcContainer.spcData.versionUsed == SPCVersion::v1 as u32) && Thank you.
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104
Activity
Feb ’26
The audio of FairPlay protected content can be captured - Safari on iOS
Hi, Has anyone been able to protect the audio part of FairPlay protected content from being captured as part of screen recording on Safari/iOS (PWA and/or online web app)? We have tried many things but could not prevent the audio from being recorded. Same app and content on Safari/Mac does not allow audio to be recorded. Any tips?
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1
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0
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193
Activity
1w
Unity iOS (Metal) → WebRTC (Unity WebRTC) video stream to remote Unity client: PeerConnection connects but receiver renders black frames
Hello! My name is Mason Prather. I'm a graduate student at Kennesaw State University and a Research Engineer working in XR environments through my Graduate Research Assistant role. I’m currently building a research prototype that connects a mobile companion application to a VR headset. The mobile application is built in Unity and deployed on iOS, and it streams video frames to a remote Unity client using WebRTC. Environment Device: iPhone 15 OS: iOS 26.3 (tested on physical device, not Simulator) Engine: Unity 2022.3.57f1 Graphics API: Metal Streaming Technology: WebRTC (Unity WebRTC package) Architecture: Mobile Unity app streaming video frames to a remote Unity client Receiver Device: Meta Quest Pro headset (Unity application) Networking: LAN (UDP discovery + TCP signaling) Video Source: Unity RenderTexture Goal The goal of the system is to allow a VR user to view media stored on their phone inside a VR environment. The iOS app: renders or captures media content converts frames into a WebRTC video track streams the video to the headset Current Status Connection setup works correctly. Observed behavior: Signaling connection successful ICE candidate exchange successful PeerConnection state becomes Connected Video track created successfully However, the receiving application displays black frames. iOS App Details The video source originates from a Unity RenderTexture. Inside the phone application: RenderTexture displays correctly Frames appear correct locally But the receiving peer does not display the frames. Relevant Components Unity WebRTC package iOS Metal rendering pipeline Custom TCP signaling LAN discovery via UDP Expected Behavior Rendered frames should transmit via WebRTC and appear on the remote device. Actual Behavior The remote video track is active, but the rendered frames appear black on the receiving client. Questions Are there known issues involving Unity WebRTC + iOS Metal texture capture? Are there specific pixel format requirements when streaming textures from Unity on iOS? Could the issue relate to texture readback limitations or GPU synchronization? I am more than happy to provide screenshots and console logs upon request. If anyone has experience streaming Unity video frames via WebRTC on iOS, I would greatly appreciate any guidance.
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218
Activity
Mar ’26
On iOS 26, HLS alternate audio track selection behaves inconsistently
Summary On iOS 26, HLS alternate audio track selection behaves inconsistently on both VOD and live streams: the French track falls back to the DEFAULT=YES (English) track after manual selection, and in some cases switching to a non-default track appears to work but it is then impossible to switch back to English. Environment iOS version: 26 Players affected: native Safari on iOS 26 and THEOplayer (issue also reproducible on THEOplayer's own demo page) Stream type: HLS/CMAF with demuxed alternate audio renditions (CMFC container) Affected stream types: both VOD and live streaming Issue NOT present on iOS 17/18 Manifest #EXTM3U #EXT-X-VERSION:4 #EXT-X-INDEPENDENT-SEGMENTS #EXT-X-STREAM-INF:BANDWIDTH=8987973,AVERAGE-BANDWIDTH=8987973,VIDEO-RANGE=SDR,CODECS="avc1.640028",RESOLUTION=1920x1080,FRAME-RATE=29.970,AUDIO="program_audio" video_1080p.m3u8 #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="program_audio",LANGUAGE="en",ASSOC-LANGUAGE="en",NAME="English",AUTOSELECT=YES,DEFAULT=YES,CHANNELS="2",URI="audio_ENG.m3u8" #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="program_audio",LANGUAGE="de",ASSOC-LANGUAGE="de",NAME="Deutsch",AUTOSELECT=YES,DEFAULT=NO,CHANNELS="2",URI="audio_DEU.m3u8" #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="program_audio",LANGUAGE="fr",ASSOC-LANGUAGE="fr",NAME="Francais",AUTOSELECT=YES,DEFAULT=NO,CHANNELS="2",URI="audio_FRA.m3u8" Steps to Reproduce Load the HLS manifest (VOD or live) in Safari on iOS 26, or in any AVFoundation-backed player Start playback — English plays correctly as DEFAULT Manually select "Francais" from the audio track selector Observe that English audio continues playing (French does not play) In a separate scenario: manually select "Deutsch" — German plays correctly Attempt to switch back to English — English does not resume; audio remains on the previously selected track Expected behavior Selecting any track should immediately switch to that language Switching back to English (DEFAULT=YES) should work at any time Behavior should be consistent across VOD and live streams Actual behavior Two distinct anomalies observed, reproducible on both VOD and live streams, in both native Safari and THEOplayer: French-specific fallback: selecting the French track causes playback to fall back to English. This does not happen with German. Cannot return to English: in cases where a non-default track plays correctly, attempting to switch back to the DEFAULT=YES track (English) fails — the previous non-default track continues playing. The fact that the issue reproduces in native Safari confirms this is an AVFoundation/WebKit-level regression, not a third-party player bug. What we have already verified and ruled out LANGUAGE codes are BCP-47 compliant (en, fr, de) ✓ EXT-X-VERSION:4 is present ✓ Audio codec removed from STREAM-INF CODECS (video-only) ✓ ASSOC-LANGUAGE attribute added matching LANGUAGE value ✓ Container metadata verified via ffprobe: mdhd box correctly contains language tags (e.g. "fra") ✓ Audio segment content verified via ffplay: correct audio in each language file ✓ French audio source file contains correct French audio content ✓ Issue reproduces in native Safari on iOS 26, confirming it is not a THEOplayer-specific bug Issue does NOT reproduce on iOS 17/18 with the same manifest and segments Additional notes The VOD stream is packaged with AWS MediaConvert, CMAF output group, SEGMENTED_FILES, AAC-LC codec (mp4a.40.2), 128kbps, 48kHz stereo. English uses AudioTrackType ALTERNATE_AUDIO_AUTO_SELECT_DEFAULT; French and German use ALTERNATE_AUDIO_AUTO_SELECT. The live stream uses AWS MediaPackage with a similar CMAF/HLS output configuration. Please advise whether this is a known regression in AVFoundation on iOS 26 and whether a fix is planned.
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3w
Generating a new FPS certificate (SDK 26) alongside an existing SDK 4 certificate
Hi, Our client currently has an FPS deployment certificate generated with SDK version 4 that is still actively used in production. They would like to generate an additional certificate using SDK version 26. Before doing so, they just want to confirm: Will the existing SDK 4 certificate remain unaffected and still visible in the Apple Developer portal? Any considerations they should keep in mind? Thanks! :)
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2w
Generating a new FPS certificate (SDK 26) alongside an existing SDK 4 certificate
Hi, Our client currently has an FPS deployment certificate generated with SDK version 4 that is still actively used in production. They would like to generate an additional certificate using SDK version 26. Before doing so, they just want to confirm: Will the existing SDK 4 certificate remain unaffected and still visible in the Apple Developer portal? Any considerations they should keep in mind? Thanks!
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143
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2w
Technical guidance request: native screen capture protection on macOS with Flutter while allowing AirPlay
Hello Apple Developer Support, I am reaching out for technical guidance regarding screen capture protection behavior on macOS. We are building a desktop application using Flutter running on macOS, and we have implemented native Swift code inside the macOS Runner in order to protect sensitive content from screen recording and screen sharing. Our current implementation relies on native window-level protection and display state handling from Swift, while the main UI remains rendered by Flutter. The main challenge we are facing is the following: we need to keep a strong native anti-recording protection on macOS the application is heavily used with AirPlay and screen mirroring currently, AirPlay / mirroring is often interpreted by the system similarly to screen capture or screen recording this causes our protected content to be replaced by a gray or blank area even during legitimate AirPlay usage In practice, we would like to allow: AirPlay legitimate external display / mirroring usage while still preventing: screen recording screen sharing unauthorized screen capture We would like to know whether Apple recommends an official supported approach for this use case, preferably using public APIs. More specifically: Is there an officially supported way on macOS to distinguish AirPlay mirroring from screen recording / screen sharing? Is "NSWindow.sharingType" the recommended public API for this scenario? Is there a recommended approach when the UI surface is rendered through Flutter / Metal? Are there any best practices with ScreenCaptureKit for protecting content without affecting AirPlay? We understand that some lower-level APIs may not be officially supported, so we would greatly appreciate guidance toward a public and future-proof implementation path. Thank you very much for your time and support. Best regards, Tony
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Activity
4d
Playback Issues for DRM content when sending CMCD
Since iOS and tvOS 18, CMCD can now be automatically sent by AVPlayer (https://aninterestingwebsite.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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584
Activity
Oct ’25
Install HTTP Live Streaming Tools on Linux ARM
Is there a way to install HLS tools on ARM Linux? The only one I can find is for x86 Linux. I'm working on a project on a Raspberry Pi. I'd like to install the tool to generate my hls files, but the alternatives are more complicated to use. Is there a way to run them like Mac OS does with Rosseta?
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164
Activity
Apr ’25
AVAssetWriterInputTaggedPixelBufferGroupAdaptor Hanging With Tagged Buffers
We've successfully implemented an AVAssetWriter to produce HLS streams (all code is Objective-C++ for interop with existing codebase) but are struggling to extend the operations to use tagged buffers. We're starting to wonder if the tagged buffers required for an MV-HEVC signal are fully supported when producing HLS segments in a live-stream setting. We generate a live stream of data using something like: UTType *t = [UTType typeWithIdentifier:AVFileTypeMPEG4]; m_writter = [[AVAssetWriter alloc] initWithContentType:t]; // - videoHint describes HEVC and width/height // - m_videoConfig includes compression settings and, when using MV-HEVC, // the correct keys are added (i.e. kVTCompressionPropertyKey_MVHEVCVideoLayerIDs) // The app was throwing an exception without these which was // useful to know when we got the configuration right. m_video = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo outputSettings:m_videoConfig sourceFormatHint:videoHint]; For either path we're producing CVPixelBufferRefs that contain the raw pixel information (i.e. 32BGRA) so we use an adapter to make that as simple as possible. If we use a single view and a AVAssetWriterInputPixelBufferAdaptor things work out very well. We produce segments and the delegate is called. However, if we use the AVAssetWriterInputTaggedPixelBufferGroupAdaptor as exampled in the SideBySideToMVHEVC demo project, things go poorly. We create the tagged buffers with something like: CMTagCollectionRef collections[2]; CMTag leftTags[] = { CMTagMakeWithSInt64Value( kCMTagCategory_VideoLayerID, (int64_t)0), CMTagMakeWithSInt64Value( kCMTagCategory_StereoView, kCMStereoView_LeftEye) }; CMTagCollectionCreate( kCFAllocatorDefault, leftTags, 2, &(collections[0]) ); CMTag rightTags[] = { CMTagMakeWithSInt64Value( kCMTagCategory_VideoLayerID, (int64_t)1), CMTagMakeWithSInt64Value( kCMTagCategory_StereoView, kCMStereoView_RightEye) }; CMTagCollectionCreate( kCFAllocatorDefault, rightTags, 2, &(collections[1]) ); CFArrayRef tagCollections = CFArrayCreate( kCFAllocatorDefault, (const void **)collections, 2, &kCFTypeArrayCallBacks ); CVPixelBufferRef buffers[] = {*b, *alt}; CFArrayRef b = CFArrayCreate( kCFAllocatorDefault, (const void **)buffers, 2, &kCFTypeArrayCallBacks ); CMTaggedBufferGroupRef bufferGroup; OSStatus res = CMTaggedBufferGroupCreate( kCFAllocatorDefault, tagCollections, b, &bufferGroup ); Perhaps there's something about this OBJC code that I've buggered up? Hopefully! Anyways, when I submit this tagged bugger group to the adaptor: if (![mvVideoAdapter appendTaggedPixelBufferGroup:bufferGroup withPresentationTime:pts]) { // report error... } Appending does not raise any errors - eventually it just hangs on us and we never return from it... Real Issue: So either: The delegate assigned to the AVAssetWriter doesn't fire its assetWriter callback which should produce the segments The adapter hangs on the appendTaggedPixelBufferGroup before a segment is ready to be completed (but succeeds for a number of buffer groups before this happens). This is the same delegate class that's assigned to the non multi view code path if MV-HEVC is turned off which works perfectly.
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124
Activity
Apr ’25
FPS Certificate Re-issuance and Validity of Existing Certificate
Keywords: FairPlay, FPS Certificate, DRM, FairPlay Streaming, license server Hi all, We are currently using FairPlay Streaming in production and already have an FPS certificate in place. However, the passphrase for the existing FPS certificate has unfortunately been lost. We are now considering reissuing a new FPS certificate, and I would like to confirm a few points before proceeding: 1️⃣ If we reissue a new FPS certificate, will the existing certificate be automatically revoked? Or will it remain valid until its original expiration date? 2️⃣ Is it possible to have both the newly issued and the existing certificates valid at the same time? In other words, can we serve DRM licenses using either certificate depending on the packaging or client? 3️⃣ Are there any caveats or best practices we should be aware of when reissuing an FPS certificate? For example, would existing packaged content become unplayable, or would CDN/packaging server configurations need to be updated carefully? Since this affects our production environment, we would like to minimize any service disruption or compatibility issues. Unfortunately, when we contacted Apple support directly, we were advised to post this question here in the Forums for additional guidance. Any advice or experiences would be greatly appreciated! Thank you in advance.
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204
Activity
Jun ’25
Disconnect from AirPlay device programmatically
Hello there, I'm trying to implement feature which uses AirPlay with Apple TV. I want to disconnect from the device programmatically when something happens. Under something I mean a situation when a user wants to stop broadcasting (for example close the PiP window on his phone). I use this snippet: try audioSession.setCategory(.playAndRecord, options: .defaultToSpeaker) try audioSession.setActive(true, options: .notifyOthersOnDeactivation) It works fine sometimes but not always (it works on iOS 18 but it doesn't on iOS 17 or ). So I thought it's a bug and create a ticker to feedback assistant (FB21220013). The support told me write a post on the forum.
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479
Activity
Dec ’25
Cannot generate 2048-bit FairPlay Streaming certificate
Hello, I have a problem generating a 2048-bit FairPlay Streaming certificate. I tried generating SDK v26.x certificate in two ways. (1) Use existing certificate (2) Create new certificate Though, in both ways, Apple gives me a certificate bundle of 1024-bit certificate. (fps_certificate.bin) I've uploaded 2048-bit CSR on creating a certificate. Just to note, I have created a SDK v4.x certificate few years ago. Have anyone bumped into a same issue? Or am I missing something?
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1k
Activity
Feb ’26
Crash when trying to get originatingRecipient
According to the documentation (https://aninterestingwebsite.com/documentation/avfoundation/avcontentkeyrequest/originatingrecipient?changes=_3&language=objc), starting with ios 18.4, I can get AVContentKeyRecipient from AVContentKeyRequest. But when I try to get it, I get a crash. What could be the issue? I want to note that I add the asset to the AVContentKeySession using the addContentKeyRecipient method (https://aninterestingwebsite.com/documentation/avfoundation/avcontentkeysession/addcontentkeyrecipient(_:)?changes=_3&language=objc).
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Activity
Feb ’26
Inquiry regarding CoreMediaErrorDomain Code=-15517 during LL-HLS Live Playback
Hello, I am currently developing a live streaming application using AVPlayer to play LL-HLS (Low-Latency HLS) content. During our testing phase, we consistently encountered the following error in the logs: CoreMediaErrorDomain Code=-15517 The challenge we are facing is that the error description is quite vague. It only provides cryptic messages such as "Key not found" or "No value information," which makes it extremely difficult to identify the root cause or perform a deep-dive analysis. I have searched through the official Apple Developer documentation and technical notes, but I couldn’t find any specific reference to what Code -15517 signifies in the context of LL-HLS or CoreMedia. Regarding this issue, I have the following questions: What is the specific meaning of this error code (-15517)? Does it relate to missing tags in the HLS manifest, or is it an internal state issue within the AVPlayer stack? 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. Is there any additional logging or debugging tool you would recommend to further investigate "Key not found" issues in LL-HLS? Any insights or guidance from the community or Apple engineers would be greatly appreciated. Thank you in advance for your help.
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196
Activity
Feb ’26
Offline Fairplay Error -42650
We have implemented offline Fairplay playback and it works fine.But at times when trying to playback the offline downloaded content, we get the following error"An unknown error occured (-42650)"Tried looking up the error in the documentation but couldnt find anything relevant.What could possibly be creating this error?
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Activity
3w
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