Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.

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Frame Discontinuity Reasons
I have an app that uses a MultiCamCaptureSession, the devices of which are builtInUltraWideCamera and builtInLiDARDepthCamera cameras. Occasionally when outside I get some frame drops due to discontinuity that end in the media services being reset: [06-24 11:27:13][CameraSession] Capture session runtime error: related decl 'e' for AVError(_nsError: Error Domain=AVFoundationErrorDomain Code=-11819 "Cannot Complete Action" UserInfo={NSLocalizedDescription=Cannot Complete Action, NSLocalizedRecoverySuggestion=Try again later.}) This runtime error notification is always superseded by 4-5 frame drops : [06-24 11:27:10][CaptureSession] Dropped frame because Discontinuity Logging the system temperature shows [06-24 11:27:10][CaptureSession] Temperature is 'Fair' I have some inclination that the frame discontinuity is being caused by the whileBalanceMode of the capture session, perhaps the algorithm requires 5 recent frames to work. I had a similar problem with the lidar depth camera where with filtering enabled exactly 5 frame drops would make the media services reset. When the whiteBalanceMode is locked I do slightly better with 10 frame drops before the mediaServices are reset. Is there any logging utility to determine the actual reason? All of these sampleBuffers come with no info attachment only the not so useful "Dropped frame because Discontinuity." Any ideas for solving this would be helpful as well. Maybe tuning the camera to work better with quickly varying lighting conditions?
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Integrating Apple Music Subscriptions into a React Native App
Hi everyone, I'm currently developing an iOS app using React Native and recently got accepted into the Apple Music Global Affiliate Program. To fully utilize this opportunity, I need to implement the following functionalities: Authorize Apple Music usage Play Apple Music within my app Identify if a user has an Apple Music subscription Initiate and complete Apple Music subscription within my app I've successfully implemented the first three functionalities using the react-native-apple-music module. Now, I need your help to understand how I can directly trigger the Apple Music subscription process from within my app. Thank you for your help!
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HLS Playback Issue with Discontinuity Tag and Low Bitrate Streams and Seek on iOS 17
I am writing to report an issue encountered with the playback of HLS (HTTP Live Streaming) streams that I believe is specific to iOS version 17. The problem manifests when certain conditions are met during the playback of concatenated HLS segments, particularly those with low video bitrate. Below, I will detail the background, symptoms, and steps required to reproduce the issue. Background: Our business scenario requires concatenating two HLS playlists, referred to as 1.m3u8 and 2.m3u8, into a single playlist 12.m3u8. An example of such a playlist is as follows: #EXTM3U #EXT-X-VERSION:3 #EXT-X-ALLOW-CACHE:YES #EXT-X-TARGETDURATION:2 #EXT-X-MEDIA-SEQUENCE:0 #EXTINF:2.0, 1.1.ts #EXTINF:2.0, 1.2.ts #EXTINF:2.0, 1.3.ts #EXT-X-DISCONTINUITY #EXTINF:2.0, 2.1.ts #EXTINF:2.0, 2.2.ts #EXT-X-ENDLIST Problem Symptoms: On PC web browsers, Android devices, and iOS versions 13 and 15, the following is observed: Natural playback completion occurs without any issues. Seeking to different points within the stream (e.g., from 3 seconds to 9 seconds) works as expected. However, on iOS version 17, there is a significant issue: Natural playback completion is unaffected. When seeking to various points within the first playlist (1.m3u8) after playing for 1, 2, or 3 seconds, the audio for the last 3 seconds of 1.m3u8 gets lost. Conditions for Replication: The issue only arises when all the following conditions are satisfied: The video content is generated from a single image and an audio track, ensuring sound presence in the final 3 seconds. The video stream bitrate is below 500 Kbps. (Tested with 1393 Kbps bitrate, which did not trigger the issue.) The HLS streams are concatenated using the #EXT-X-DISCONTINUITY tag to form a virtual 11.m3u8 playlist. (No issues occur when streams are not concatenated.) Seek operations are performed during playback. (No issues occur without seek operations.) The issue is exclusive to iOS version 17. (No issues reported on iOS versions 13 and 15.) Disrupting any one of these conditions results in normal playback behavior. Steps to Reproduce: Using FFmpeg, generate a video from a single image and an audio track, with a suggested duration of 10 to 20 seconds for testing convenience. If the video's bitrate exceeds 1000 Kbps, consider transcoding it to 500 Kbps or lower to avoid potential edge-case issues. Convert the 1.mp4 file into 1.m3u8 using FFmpeg. The segment duration can be set to between 1 and 5 seconds (tested with both 2-second and 5-second durations). Duplicate 1.m3u8 as 2.m3u8, then concatenate 1.m3u8 and 2.m3u8 into 12.m3u8 as shown below: #EXTM3U #EXT-X-VERSION:3 #EXT-X-ALLOW-CACHE:YES #EXT-X-TARGETDURATION:2 #EXT-X-MEDIA-SEQUENCE:0 #EXTINF:2.0, 1.1.ts #EXTINF:2.0, 1.2.ts #EXT-X-DISCONTINUITY #EXTINF:2.0, 1.1.ts #EXTINF:2.0, 1.2.ts #EXT-X-ENDLIST On an iOS 17 device, play 12.m3u8 for 1, 2, or 3 seconds, then seek to any point between 7 and 9 seconds (within the duration of 1.m3u8). This action results in the loss of audio for the last 3 seconds of 1.m3u8.
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Crash with AVMutableComposition insertTimeRange Method
A small number of crashes are being reported on Firebase. When attempting to use the insertTimeRange:ofAsset:atTime:error: method of AVMutableComposition, a crash occurred with the error message -[__NSArrayM insertObject:atIndex:]: object cannot be nil. Most of them appear in versions of ios 17.0 and above. Here's my code: - (AVMutableComposition *)createtrimAsset:(AVAsset *)asset andStartTime:(CGFloat)startTime endTime:(CGFloat)endTime{ NSError *error = nil; CGFloat timescale = 1000000; AVMutableComposition *mutableComposition = [AVMutableComposition composition]; CMTime sStartTime = CMTimeMakeWithSeconds(CMTimeGetSeconds(asset.duration)*startTime, timescale); CMTime eEndTime = CMTimeMakeWithSeconds(CMTimeGetSeconds(asset.duration)*endTime, timescale); [mutableComposition insertTimeRange:CMTimeRangeMake(sStartTime, CMTimeSubtract(eEndTime, sStartTime)) ofAsset:asset atTime:kCMTimeZero error:&error]; return mutableComposition; } I attempted to reproduce this crash by deliberately setting the timeRange or asset to unusual values, such as asset=nil, or asset.duration=0, or asset.duration=NAN, but all attempts failed. What could be causing this exception? Any advice would be of great help to me.
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When adding a VideoPlayerComponent to an Entity placed in ImmersiveSpace and attempting to play an 8K video, the application crashes.
OS:VisionOS 1.0 Xcode:15.2 In the application under development, do the following Open ImmersiveSpace Add VideoPlayerComponent to Entity Play 8K Video the App crash The Apple symbol appears and returned to the Home but, The problem does not occur if the application is created by extracting only the part of the 8K video to be played back. Error Log apply fence tx failed (client=0x6fbf0fcc) [0xfffffecc (ipc/mig) server died] Failed to commit transaction (client=0x58510d43) [0x10000003 (ipc/send) invalid destination port] nw_read_request_report [C1] Receive failed with error "No message available on STREAM" nw_protocol_socket_reset_linger [C1:2] setsockopt SO_LINGER failed [22: Invalid argument] Failed to set override status for bind point component member. Message from debugger: Terminated due to signal 9 I can't share the entire application, but is anyone else experiencing the same problem? Is this a memory issue?
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When VideoTool Box compress JPEG and H264, the output format(YUV420) is different from the input format.
The M series utilizes VideoToolBox GPU compression with a YUV422 format kCVPixelFormatType_422YpCbCr8BiPlanarVideoRange input, and the compressed output JPEG image format remains YUV420. For the Intel series GPU compression, a YUV420 format kCVPixelFormatType_420YpCbCr8Planar input is required, and the compressed output JPEG image format is YUV422. The output format after compression is not consistent with the input format. Does VideoToolBox GPU compression support output YUV422 or YUV444 JPEG images and H.264 streams?
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Focus Peaking/Contrast Detection as seen in Final Cut Camera App
Hello everyone, with the release of Apple's new Final Cut Camera App, we see the possibility to overlay a Focus Peaking indicator over the camera feed, showing focussed areas. We have already had a contrast based autofocus system for some time via the AVCaptureDevice.Format.AutoFocusSystem.contrastDetection, but I haven't found a way to actually present contrast areas to the user. Given that Apple now natively has such an algorithm for the Final Cut Camera App, I wonder if we devs now also get access to this. If not, does anybody know of implementations of focus peaking out there? Thanks and with best regards
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WWDC Lab feedback
I am writing to follow up with my lab in WWDC24. I had 1:1 lab with Mr. Kavin, we had good 30 minutes lab and for follow up questions Kavin asked me to post it using feedback. Following is my questin: We have screenshare in our application and trying to use CFMessagePort for passing CVPixelBufferRef from broadcast extension to Applicaiton. Questions: How to copy planes of IOSurface backed CVPixelBufferRef onto another one without using memcpy, is there a zero-copy method? How to get notified when an IOSurface backed CVPixelBufferRef data get changed by another process. How to send an IOSurface backed CVPixelBufferRef from Broadcast Extension to application. How to pass unowned IOSurfaceRef from the Broadcast Extension to appliction.
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Audio transition using MPMusicPlayerApplicationController
Hi. I saw that in iOS 18 Beta there is a property "transition" on the Music Kit's ApplicationMusicPlayer. However, in my app I am using MPMusicPlayerApplicationController because I want to play Apple Music songs, local songs and podcasts. But I didn't find an analogue property on MPMusicPlayerApplicationController to specify transitions between songs. Am I missing something? Thanks, Dirk
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Add the info of each picture in the photo app, which is derived from the name of the user's self-built album.
Well, I will collect a lot of memes from the Internet and save them on my iPhone. I will name and classify them, but I will click on a photo in "All Photos", and its info does not show which album I added to, which makes me very distressed. If I have this function, I will easily manage the memes that I did not correctly add to the corresponding album.
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ProRes 4444 blocky compression artifacts
I’m creating a objective C command-line utility to encode RAW image sequences to ProRes 4444, but I’m encountering, blocky compression artifacts in the ProRes 4444 video output. To test the integrity of the image data before encoding to ProRes, I added a snippet in my encoding function that saves a 16-bit PNG before encoding to ProRes and the PNG looks perfect, I can see all detail in every part of the image dynamic range. Here’s a comparison between the 16-bit PNG(on the right) and the ProRes 4444 output. (on the left) As a further test, I re-encoded the ‘test PNG’ to ProRes 4444 using DaVinci Resolve, and the ProRes4444 output video from Resolve doesn’t have any blocky compression artifacts. Looks identical. In short, this is what the utility does: Unpacks the 12-bit raw data into 16-bit values. After unpacking, the raw data is debayered to convert it into a standard color image format (BGR) using OpenCV. Scale the debayered pixel values from their original 12-bit depth to fit into a 16-bit range. Up to this point everything is fine and confirmed by saving 16bit PNGs. The images are encoded to ProRes 4444 using the AVFoundation framework. The pixel buffers are created and managed using dictionary method with ‘kCVPixelFormatType_64RGBALE’. I need help figuring this out, I’m a real novice when it comes to AVfoundation/encoding to ProRes. See relevant parts of my 'encodeToProRes' function: void encodeToProRes(const std::string &outputPath, const std::vector<std::string> &rawPaths, const std::string &proResFlavor) { NSError *error = nil; NSURL *url = [NSURL fileURLWithPath:[NSString stringWithUTF8String:outputPath.c_str()]]; AVAssetWriter *assetWriter = [AVAssetWriter assetWriterWithURL:url fileType:AVFileTypeQuickTimeMovie error:&error]; if (error) { std::cerr << "Error creating AVAssetWriter: " << error.localizedDescription.UTF8String << std::endl; return; } // Load the first image to get the dimensions std::cout << "Debayering the first image to get dimensions..." << std::endl; Mat firstImage; int width = 5320; int height = 3900; if (!debayer_image(rawPaths[0], firstImage, width, height)) { std::cerr << "Error debayering the first image" << std::endl; return; } width = firstImage.cols; height = firstImage.rows; // Save the first frame as a PNG 16-bit image for validation std::string pngFilePath = outputPath + "_frame1.png"; if (!imwrite(pngFilePath, firstImage)) { std::cerr << "Error: Failed to save the first frame as a PNG image" << std::endl; } else { std::cout << "First frame saved as PNG: " << pngFilePath << std::endl; } NSString *codecKey = nil; if (proResFlavor == "4444") { codecKey = AVVideoCodecTypeAppleProRes4444; } else if (proResFlavor == "422HQ") { codecKey = AVVideoCodecTypeAppleProRes422HQ; } else if (proResFlavor == "422") { codecKey = AVVideoCodecTypeAppleProRes422; } else if (proResFlavor == "LT") { codecKey = AVVideoCodecTypeAppleProRes422LT; } else { std::cerr << "Error: Invalid ProRes flavor specified: " << proResFlavor << std::endl; return; } NSDictionary *outputSettings = @{ AVVideoCodecKey: codecKey, AVVideoWidthKey: @(width), AVVideoHeightKey: @(height) }; AVAssetWriterInput *videoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:outputSettings]; videoInput.expectsMediaDataInRealTime = YES; NSDictionary *pixelBufferAttributes = @{ (id)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_64RGBALE), (id)kCVPixelBufferWidthKey: @(width), (id)kCVPixelBufferHeightKey: @(height) }; AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:videoInput sourcePixelBufferAttributes:pixelBufferAttributes]; ... [assetWriter startSessionAtSourceTime:kCMTimeZero]; CMTime frameDuration = CMTimeMake(1, 24); // Frame rate of 24 fps int numFrames = static_cast<int>(rawPaths.size()); ... // Encoding thread std::thread encoderThread([&]() { int frameIndex = 0; std::vector<CVPixelBufferRef> pixelBufferBuffer; while (frameIndex < numFrames) { std::unique_lock<std::mutex> lock(queueMutex); queueCondVar.wait(lock, [&]() { return !frameQueue.empty() || debayeringFinished; }); if (!frameQueue.empty()) { auto [index, debayeredImage] = frameQueue.front(); frameQueue.pop(); lock.unlock(); if (index == frameIndex) { cv::Mat rgbaImage; cv::cvtColor(debayeredImage, rgbaImage, cv::COLOR_BGR2RGBA); CVPixelBufferRef pixelBuffer = NULL; CVReturn result = CVPixelBufferPoolCreatePixelBuffer(NULL, adaptor.pixelBufferPool, &pixelBuffer); if (result != kCVReturnSuccess) { std::cerr << "Error: Could not create pixel buffer" << std::endl; dispatch_group_leave(dispatchGroup); return; } CVPixelBufferLockBaseAddress(pixelBuffer, 0); void *pxdata = CVPixelBufferGetBaseAddress(pixelBuffer); for (int row = 0; row < height; ++row) { memcpy(static_cast<uint8_t*>(pxdata) + row * CVPixelBufferGetBytesPerRow(pixelBuffer), rgbaImage.ptr(row), width * 8); } CVPixelBufferUnlockBaseAddress(pixelBuffer, 0); pixelBufferBuffer.push_back(pixelBuffer); ... Thanks very much!
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How to identify audio and video AVCaptureDevices that are from the same hardware?
I'm working on a macOS application that captures audio and video. When the user selects a video capture source (most likely an elgato box), I would like the application to automatically select the audio input from the same device. I was achieving this by pairing video and audio sources that had the same name, but this doesn't work when the user plugs in two capture devices of the same make and model. With the command system_profiler SPUSBDataType I can list all the USB devices, and I can see that the two elgato boxes have different serial numbers. If I could find this serial number, then I could figure out which AVCaptureDevices come from the same hardware. Is there a way to get the manufacturer's serial number from the AVCaptureDevice object? Or a way to identify the USB device for an AVCaptureDevice, and from there I could get the serial or some other unique ID?
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Is it required to update photo metadata to set 1 for Orientation?
I've had an app that edits photos in your library since the PhotoKit API was released in iOS 8. I know it was required if you preserve photo metadata you had to change the value of Orientation to 1 (up), otherwise PhotoKit would fail to perform the asset change request. When I remove this code, I'm seeing Orientation is getting changed to 1 automatically both at root and in the TIFF dictionary (tested with iOS 18). I wanted to confirm this is expected behavior, the system does this for us now? If so, can I remove this code for iOS 15+, or was it a recent iOS version this started happening? Thanks!
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Sort user library assets by date captured instead of recently added
Is it possible to sort the user library assets by date captured? The Photos app in iOS 18 lets you choose between Date Captured and Recently Added and I want to offer that same choice in my app. This seems to always sort them by creation date (which I believe is the same as recently added): let assetCollection = PHAssetCollection.fetchAssetCollections(with: .smartAlbum, subtype: .smartAlbumUserLibrary, options: nil).firstObject! let fetchResult = PHAsset.fetchAssets(in: assetCollection, options: PHFetchOptions.imageMediaType())
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Error 15517 when playing HLS
Playing fMP4 HLS stream on VisionOS beta. This is the stream, HEVC main 10 and EAC3 6 channel: #EXT-X-STREAM-INF:BANDWIDTH=6760793,AVERAGE-BANDWIDTH=6760793,VIDEO-RANGE=PQ,CODECS="hvc1.2.4.L150.B0,mp4a.a6",RESOLUTION=3840x2160,FRAME-RATE=23.976,SUBTITLES="subs" This is what AVPlayer says: Error Domain=AVFoundationErrorDomain Code=-11848 "Cannot Open" UserInfo={NSLocalizedFailureReason=The media cannot be used on this device., NSLocalizedDescription=Cannot Open, NSUnderlyingError=0x3009e37b0 {Error Domain=CoreMediaErrorDomain Code=-15517 "(null)"}} I can't find any documentation for the underlying error 15517. Is it because "mp4a.a6" is declared in the codec list and not "ec-3"? hlsreport has these MUST FIX issues: 1. Measured peak bitrate compared to multivariant playlist declared value exceeds error tolerance Multivariant Playlist Stream Definition for All Variants 2. Stereo audio in AAC-LC, HE-AAC v1, or HE-AAC v2 format MUST be provided Multivariant Playlist 3. If Dolby Digital Plus is provided then Dolby Digital MUST be provided also Multivariant Playlist 4. I-frame playlists ( EXT-X-I-FRAME-STREAM-INF ) MUST be provided to support scrubbing and scanning UI Multivariant Playlist 5. The server MUST deliver playlists using gzip content-encoding All Variants All Renditions Multivariant Playlist 6. You MUST provide multiple bit rates of video Multivariant Playlist 7. Playlist codec type doesn't match content codec type All Variants 8. (Segment) The operation couldn’t be completed. (HTTPPumpErrorDomain error -16845 - HTTP 400: (unhandled)) (list of subtitle renditions) 9. (Segment) HTTP 400 - HTTP/2.0 400 Bad Request (list of subtitle renditions) 10. Multichannel audio MUST be separate audio stream All Variants 11. If EXT-X-INDEPENDENT-SEGMENTS is not in the multivariant playlist, then you MUST use the EXT-X-INDEPENDENT-SEGMENTS tag in all video media playlists All Variants 12. The CODECS attribute MUST include every media format present All Variants, does not declare EC-3
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