Because I want to control the grid size and number of HEIC images myself, I decided to perform HEVC encoding manually and then generate the HEIC image. Previously, I used VTCompressionSession to accomplish this task, and the results were satisfactory. It worked perfectly on iOS 16 through iOS 18 — in other words, it was able to generate correct HEVC encoding, and its CMFormatDescription should also have been correct, since I relied on it to generate the decoderConfig; otherwise, the final image would have decoding issues.
However, it can no longer generate a valid HEIC image on a physical device running iOS 26. Interestingly, it still works fine on the iOS 26 simulator — it only fails on real hardware. The abnormal result is that the image becomes completely black, although the image dimensions are still correct.
After my troubleshooting, I suspect that the encoding behavior of VTCompressionSession has been modified on iOS 26, which causes the final hvc1 encoding I pass in to be incorrect.
I created a VTCompressionSession using the following configuration.
var newSession: VTCompressionSession!
var status = VTCompressionSessionCreate(
allocator: kCFAllocatorDefault,
width: Int32(frameSize.width),
height: Int32(frameSize.height),
codecType: kCMVideoCodecType_HEVC,
encoderSpecification: nil,
imageBufferAttributes: nil,
compressedDataAllocator: nil,
outputCallback: nil,
refcon: nil,
compressionSessionOut: &newSession
)
try check(status, VideoToolboxErrorDomain)
let properties: [CFString: Any] = [
kVTCompressionPropertyKey_AllowFrameReordering: false,
kVTCompressionPropertyKey_AllowTemporalCompression: false,
kVTCompressionPropertyKey_RealTime: false,
kVTCompressionPropertyKey_MaximizePowerEfficiency: false,
kVTCompressionPropertyKey_ProfileLevel: profileLevel,
kVTCompressionPropertyKey_Quality: quality.rawValue,
]
status = VTSessionSetProperties(newSession, propertyDictionary: properties as CFDictionary)
try check(status, VideoToolboxErrorDomain) {
VTCompressionSessionInvalidate(newSession)
}
Then use the following code to encode each Grid of the image.
let status = VTCompressionSessionEncodeFrame(
session,
imageBuffer: buffer,
presentationTimeStamp: presentationTimeStamp,
duration: frameDuration,
frameProperties: nil,
infoFlagsOut: nil) { [weak self] status, _, sampleBuffer in
try check(status, VideoToolboxErrorDomain)
if let sampleBuffer {
let encodedImage = try self.encodedImage(from: sampleBuffer)
// handle encodedImage
}
}
try check(status, VideoToolboxErrorDomain)
If I try to display this abnormal image in the App, my console outputs the following error, so it can be inferred that the issue probably occurred during decoding.
createImageBlock:3029: *** ERROR: CGImageBlockCreate {0, 0, 2316, 6176} - data is NULL
callDecodeImage:2411: *** ERROR: decodeImageImp failed - NULL _blockArray
createImageBlock:3029: *** ERROR: CGImageBlockCreate {0, 0, 2316, 6176} - data is NULL
callDecodeImage:2411: *** ERROR: decodeImageImp failed - NULL _blockArray
createImageBlock:3029: *** ERROR: CGImageBlockCreate {0, 0, 2316, 6176} - data is NULL
callDecodeImage:2411: *** ERROR: decodeImageImp failed - NULL _blockArray
It needs to be emphasized again that this code used to work fine in the past, and the issue only occurs on an iOS 26 physical device. I noticed that iOS 26 has introduced many new properties, but I’m not sure whether some of these new properties must be set in the new system, and there’s no information about this in the official documentation.
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We build mobile apps for creators to edit their videos. Post editing the video, the creator has to export the video so that it can be uploaded to Youtube. The export is a time consuming and GPU intensive process. The creator can exit the app due to various reasons like receiving the call, putting the app in background etc. This causes the export to fail :(
Keeping this limitation in mind there was an announcement from Apple that with the IOS 26 launch would start to support background GPU access. Here is the official documentation: https://developer.apple.com/documentation/BundleResources/Entitlements/com.apple.developer.background-tasks.continued-processing.gpu
When we tried using this feature, we were not able to get it to work on IOS 26. We stumbled upon this ticket(https://developer.apple.com/forums/thread/797538?answerId=854825022#854825022) in the Apple Developer forum, in which possibly an Apple engineer claims it is supported ONLY for iPadOS 26. This is a very big bummer for us.
96% of the users are on iPhone(compared to iPad), and if we refer to the official documentation above, it claims that this feature should work on IOS 26.
This feature is extremely important for having the best user experience and reducing user frustration and will be useful for other video editing apps.
Looking forward to a resolution.
Topic:
Media Technologies
SubTopic:
Video
Hi everyone,
I am currently on MacOS Tahoe (26.1), and for some weird reason my mac is not connecting via HDMI. To be accurate: it is connecting and the LG TV shows up in the Displays settings, but no image shows up in it, I have no idea why. This used to work as I've tried this cable before with the same exact tv. The cable is a basic Amazon Basics HDMI one.
Allow me just to advanced this question a little: usually terminal commands are more advanced recommendations, whereas basic questions like "have you connected it right" are just a waste of time
Topic:
Media Technologies
SubTopic:
Video
Our iOS/AppleTV video content playback app uses AVPlayer to play HLS video streams and supports both custom and system playback UIs. The Fairplay content key is retrieved using AVContentKeySession. AirPlay is supported too.
When the iPhone is connected to a TV through the lightning Apple Digital AV Adapter (A1438), the app is mirrored as expected.
Problem: when using an iPhone or iPad on iOS 18.1.1, FairPlay-protected HLS streams are not played and a CoreMediaErrorDomain -12035 error is received by the AVPlayerItem. Also, once the issue has occurred, the mirroring freezes (the TV indefinitely displays the app playback screen) although the app works fine on the iOS device.
The content key retrieval works as expected (I can see that 2 content key requests are made by the system by the way, probably one for the local playback and one for the adapter, as when AirPlaying) and the error is thrown after providing the AVContentKeyResponse.
Unfortunately, and as far as I know, there is not documentation on CoreMediaErrorDomain errors so I don't know what -12035 means.
The issue does not occur:
on an iPhone on iOS 17.7 (even with FairPlay-protected HLS streams)
when playing DRM-free video content (whatever the iOS version)
when using the USB-C AV Adapter (whatever the iOS version)
Also worth noting: the issue does not occur with other video playback apps such as Apple TV or Netflix although I don't have any details on the kind of streams these apps play and the way the FairPlay content key is retrieved (if any) so I don't know if it is relevant.
I noticed that AVSampleBufferDisplayLayerContentLayer is not released when the AVSampleBufferDisplayLayer is removed and released.
It is possible to reproduce the issue with the simple code:
import AVFoundation
import UIKit
class ViewController: UIViewController {
var displayBufferLayer: AVSampleBufferDisplayLayer?
override func viewDidLoad() {
super.viewDidLoad()
let displayBufferLayer = AVSampleBufferDisplayLayer()
displayBufferLayer.videoGravity = .resizeAspectFill
displayBufferLayer.frame = view.bounds
view.layer.insertSublayer(displayBufferLayer, at: 0)
self.displayBufferLayer = displayBufferLayer
DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
self.displayBufferLayer?.flush()
self.displayBufferLayer?.removeFromSuperlayer()
self.displayBufferLayer = nil
}
}
}
In my real project I have mutliple AVSampleBufferDisplayLayer created and removed in different view controllers, this is problematic because the amount of leaked AVSampleBufferDisplayLayerContentLayer keeps increasing.
I wonder that maybe I should use a pool of AVSampleBufferDisplayLayer and reuse them, however I'm slightly afraid that this can also lead to strange bugs.
Edit: It doesn't cause leaks on iOS 18 device but leaks on iPad Pro, iOS 17.5.1
Safari is supposed to support animated AVIF images since version 16, but the ones I've tested perform very poorly, even on an M4 Mac Mini running Sequoia 15.1.1.
I believe Safari delegates decoding to the operating system itself, so this issue also happens in Live Preview in the finder, when I try to preview a file.
Sample file here: https://s3.us-west-2.amazonaws.com/cdn.paintera.org/test/sample.avif
322KB file, 5 seconds long, 12fps
This plays perfectly on Chrome on Mac OS, but is slow and laggy on Safari and Live Preview (it takes about 6.5 seconds to finish the 5 second video).
Does anyone know how to fix this or workaround this issue?
Topic:
Media Technologies
SubTopic:
Video
Hello Apple Community,
We are working on a real-time streaming feature where we receive chunks of raw MP4 data through a custom protocol and store them in a buffer (array). Our goal is to use these data chunks to play a continuous video stream in AVPlayer.
What We've Tried:
Custom URL Scheme with AVAssetResourceLoaderDelegate:
We implemented a custom URL scheme (customscheme://) to serve the buffered data using AVAssetResourceLoaderDelegate.
The method shouldWaitForLoadingOfRequestedResource is called only during the initial allocation. It doesn't get triggered when new chunks are appended to the buffer.
Despite appending new data to the buffer, AVPlayer doesn’t request further chunks from the delegate.
What We Need:
We are looking for a solution where:
The player continuously fetches data from the buffer as new chunks are added.
The playback remains smooth and uninterrupted, even with real-time data being appended.
Ideally, this solution works with AVPlayer while adhering to HLS-like behavior without implementing an HLS server.
Questions:
Is AVAssetResourceLoaderDelegate the right approach for this use case?
If so, how can we ensure shouldWaitForLoadingOfRequestedResource is called whenever new data is available in the buffer?
Are there alternative APIs or recommended patterns for playing real-time MP4 data chunks in AVPlayer?
Would implementing a custom FFmpeg-based player be necessary, or can this be achieved using AVPlayer and its APIs?
We appreciate any guidance, suggestions, or examples that can help us achieve this. Thank you!
It's 2025, and I see that trends in video storage and streaming have changed significantly. Nowadays, CDN combined with domain-based video protection is the most popular solution.
Does anyone have more insights into this technology or real-world experience with it?
Topic:
Media Technologies
SubTopic:
Video
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.
Is there any way we can detect the status of the Show When Muted and Show on Skip Back device settings in code ?
When using AVSampleBufferDisplayLayer to play uncompressed H.264 and H.265 video with B-frames more than 7, frame drops occur. The more B-frames there are, the more noticeable the frame drops become, for example 15 bframes.
Use FFmpeg to transcode a video file with visible timestamps and frame numbers (x264 or x265 ):
ffmpeg -i test.mp4 -vf "drawtext=fontsize=45:text=%{pts} %{n}:y=400" -c:v libx264 -x264-params "bframes=15:b-adapt=0" -crf 30 -y x264_bf15.mp4
ffmpeg -i test.mp4 -vf "drawtext=fontsize=45:text=%{pts} %{n}:y=400" -c:v libx265 -x265-params "bframes=15:b-adapt=0" -crf 30 -y x265_bf15.mp4
Use the demo player from this repository to reproduce the issue: https://github.com/msfrms/CustomPlayer
frame drops can be observed. And following log can be found in devices console.
mediaserverd <<<< IQ-CA >>>> piqca_gmstats_dump: FIQCA(0x1266f4000) recent frames: enqueued: 184, displayed: 138, dropped: 42, flushed: 0, evicted: 3, >16ms late: 2
PS. I was using iphone11 iOS14.6, to replay this issue.
May I ask why frame drops occur in this case?
Is there any configuration or API usage change that could help fix the frame drop issue?
Many thanks!
(This only started happening as of Xcode 26.)
I know macOS and watchOS don't support this property, but all other platforms do (did?) up until I upgraded Xcode. Now when I compile I get this:
Value of type 'AVPlayerItem' has no member 'externalMetadata'
Hello everyone,
I'm looking for a definitive clarification on how to completely disable all video stabilization, including the hardware OIS, using AVFoundation. The goal is to achieve a completely raw, unstabilized video feed, which is crucial when using external equipment like gimbals to avoid conflicting stabilization motions.
My research points to using the AVCaptureConnection property preferredVideoStabilizationMode and setting it to AVCaptureVideoStabilizationMode.off.
The documentation for the .off case states:
A mode that doesn’t stabilize video capture.
This description is slightly ambiguous. It's unclear whether this only affects software-level stabilization (EIS, EIS+OIS, etc) or if it guarantees the complete deactivation of the physical OIS module. For professional video applications, this is a critical distinction.
So, I'd like to ask the community:
Has anyone been able to definitively confirm that setting preferredVideoStabilizationMode to .off also disables the hardware OIS? Are there any known tests or documentation that prove this behavior?
Is there an alternative or more direct method to ensure the OIS module is physically inactive during video capture?
What is the community's best practice for ensuring absolutely no stabilization is applied to the video pipeline?
Any insights or shared experiences on this topic would be greatly appreciated.
Thank you!
Hi everyone,
I’m exploring using the iPhone 17 Pro with the Blackmagic ProDock in a custom capture app. The genlock functionality seems accessible via AVExternalSyncDevice and related APIs, which is great.
I’m specifically curious about external timecode coming in from the ProDock:
• Is there a public way to access the timecode feed in a custom app via AVFoundation or another Apple API?
• If so, what is the recommended approach to read or apply that timecode during capture?
• Are there any current limitations or entitlements required to access timecode from ProDock in a third-party app?
I’m excited to start integrating synchronized capture in my app, and any guidance or sample patterns would be greatly appreciated.
Thanks in advance!
— [Artem]
Topic:
Media Technologies
SubTopic:
Video
We're distributing a virtual camera with our app that does not profit in the slightest from automatically applied system video effects both to the video going in (physical camera device) or out (virtual camera device). I'm aware of setting NSCameraReactionEffectGesturesEnabledDefault in Info.plist and determining active video effects via AVCaptureDevice API. Those are obviously crutches, because having to tell users to go look for and click around in menu bar apps is the opposite of a great UX.
To make our product's video output more deterministic, I'm looking for a way to tell the CMIO subsystem that our virtual camera does not support any of the system video effects. I'm seeing properties like
AVCaptureDevice.Format.isPortraitEffectSupported and AVCaptureDevice.Format.isStudioLightSupported whose documentation refers to the format's ability to support these effects. Since we're setting a CMFormatDescription via CMIOExtensionStreamSource.formats I was hoping to find something in the extensions, but wasn't successful so far.
Can this be done?
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.
I believe this should work:
CFMutableDictionaryRef attrs = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
CFDictionaryAddValue(attrs, kCVImageBufferColorPrimariesKey, kCVImageBufferColorPrimaries_ITU_R_709_2);
CFDictionaryAddValue(attrs, kCVImageBufferTransferFunctionKey, kCVImageBufferTransferFunction_ITU_R_709_2);
CFDictionaryAddValue(attrs, kCVImageBufferYCbCrMatrixKey, kCVImageBufferYCbCrMatrix_ITU_R_709_2);
CVPixelBufferRef pixelBuffer = NULL;
CVPixelBufferCreate(kCFAllocatorDefault, width, height, kCVPixelFormatType_32ARGB, attrs, &pixelBuffer);
assert(CFDictionaryGetCount(CVBufferGetAttachments(pixelBuffer, kCVAttachmentMode_ShouldPropagate)) > 0);
But that last assert fails, so it appears the color info does not get attached.
kCVImageBufferColorPrimariesKey and the others are not one of the keys listed under BufferAttributeKeys, but I think they're supposed to be allowed because they're listed by CMVideoFormatDescriptionGetExtensionKeysCommonWithImageBuffers().
I'm hoping that putting the color matrix info in there will control how AVAssetWriter converts the RGB to YCbCr.
Topic:
Media Technologies
SubTopic:
Video
Hello,
As far as I know and in all of my testing there is no way for a user or a developer to change the frame rate of the video output on iPadOS. If you connect an iPad via a USB Hub or a USB to HDMI Adaptor and then connect it to an external monitor it will output at 59.94fps.
I have a video app where a user monitors live video at 25fps and 30fps, they often output to an external display and there are times when the external display will stutter due to the mismatch in frame rate, ie. using 25fps and outputting at 59.94fps.
I thought it was impossible to change the video output frame rate, then in V3.1 of the Blackmagic Camera App I saw an interesting change in their release notes:
‘Support for HDMI Monitoring at Sensor Rate and Resolution’
This means there is some way to modify it, not sure if this is done via a Private API that Apple has allowed Blackmagic to use. If so, how can we access this or is there a way to enable this that is undocumented?
Thanks!
When setting the now playing info for playing media in MPNowPlayingInfoCenter we can set artwork. But it seems the Apple API for creating the artwork is crashing on iOS 18 (FB15145734).
On iOS 17 this gave the warning that the completion handler was not run on the main thread.
I've tried to seek help here: https://stackoverflow.com/questions/78989543/swift-data-race-with-appkit-mpmediaitemartwork-function/78990231?noredirect=1#comment139277425_78990231
but it seems that it's not possible to override the completion handler and therefor it's up to Apple to fix this issue.
.task {
await MainActor.run {
let nowPlayingInfoCenter = MPNowPlayingInfoCenter.default()
var nowPlayingInfo = [String: Any]()
let image = NSImage(named: "image")!
// warning: data race detected: @MainActor function at MPMediaItemArtwork/ContentView.swift:22 was not called on the main thread
nowPlayingInfo[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(boundsSize: image.size, requestHandler: { _ in
// Not on main thread here!
return image
})
nowPlayingInfoCenter.nowPlayingInfo = nowPlayingInfo
}
}
I'm wondering if there is an alternative method to set the now playing artwork?
Hi all,
I'm trying to diagnose and resolve an issue with stuttering video playback using the standard AVPlayer. The video in question is a 4K, 39-second file in *.mov format, being played on an iOS device. It's served via a local HTTP server that proxies requests to a backend to fetch and process the content. The project uses end-to-end encrypted storage, which necessitates the proxy for handling data processing. While playback in offline scenarios is smooth, we are encountering issues with smooth playback during streaming. The same video streams smoothly on other platforms using the same connection, so network limitations are not a factor.
On iOS, playback is consistently choppy, with pauses every 1-3 seconds. The video does not appear to buffer adequately for smooth playback.
One particularly curious aspect is the seemingly random pattern of Content-Range requests made by the AVPlayer when streaming the video. Below is an example of the range requests:
Topic:
Media Technologies
SubTopic:
Video