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How to insert multiple AVAssets into AVMutableCompositionTrack with silence in between?
Hi, I'm recording videos frame by frame and occasionally a sound plays (from an MP3 asset). I want to composite these sounds into the video at the correct timings. But this doesn't work. Really pulling my hair out here. I've tried everything, including adding one after another and then inserting silence in between (allegedly this pushes subsequent clips back) but nothing works. Here, _currentTime is the current time according to the video frames added, which are added at 20Hz. You can see I am adding silence long enough to cover the time from the end of the last audio clip to now, plus extra padding to contain the audio we are about to add. Doesn't matter if I remove this, it just doesn't work. Sometimes I can get two pieces of audio to play but never a third and usually, only the first audio plays, and then nothing after. I'm completely stumped. func addFrame(_ pixelBuffer: CVPixelBuffer) { guard CGSize(width: pixelBuffer.width, height: pixelBuffer.height) == _outputSize else { return } let frameTime = CMTimeMake(value: Int64(_frameCount), timescale: _frameRate) if _videoInput?.isReadyForMoreMediaData == true { _pixelBufferAdaptor?.append(pixelBuffer, withPresentationTime: frameTime) _frameCount += 1 _currentTime = frameTime } } func addMP3AudioClip(_ audioData: Data) async throws { let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString + ".mp3") try audioData.write(to: tempURL) let asset = AVAsset(url: tempURL) let duration = try await asset.load(.duration) let audioTrack = try await asset.loadTracks(withMediaType: .audio).first! let currentAudioTime = _currentTime.convertScale(duration.timescale, method: .default) _audioTrack?.insertEmptyTimeRange(CMTimeRangeFromTimeToTime(start: _lastAudioClipEndTime, end: currentAudioTime)) _audioTrack?.insertEmptyTimeRange(CMTimeRangeFromTimeToTime(start: currentAudioTime, end: CMTimeAdd(currentAudioTime, duration))) let timeRange = CMTimeRangeMake(start: .zero, duration: duration) try _audioTrack?.insertTimeRange(timeRange, of: audioTrack, at: currentAudioTime) _lastAudioClipEndTime = CMTimeAdd(currentAudioTime, duration) try FileManager.default.removeItem(at: tempURL) _audioClipTimeRanges.append(CMTimeRangeMake(start: _currentTime, duration: duration)) } Thank you, -- B.
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361
Oct ’24
Cancel or quit from loadValuesAsynchronouslyForKeys?
The app needs to play remote videos. Sometimes it takes very long time (~10 seconds) to load the media and play with AVPlayer. So I use a timer to check and try to play next video if it is over 5 seconds: AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:videoUrl options:nil];// line 1 NSArray *keys = @[@"playable"]; mediaLoaded = NO; [asset loadValuesAsynchronouslyForKeys:keys completionHandler:^() { // line 2 mediaLoaded = YES; // line 4 dispatch_async(dispatch_get_main_queue(), ^{ [self.player replaceCurrentItemWithPlayerItem:[AVPlayerItem playerItemWithAsset:asset]]; [self.player playImmediatelyAtRate:playSpeed]; }); }]; dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ if (!mediaLoaded) { [self playNextVideo]; // line 3 } }); So the flow is: line 1 (of video 1)- line 2 (of video 1)- line 3 (if over 5 seconds and video 1 is not playing)- line 1 (of video 2)-... Now the problem is that seems line 2 is blocking line 1: only line 4 (for video 1 after ~10 seconds) or the completionHandler is executed will line 2 (for video 2) will be executed. Anybody can give any insight? Thx!
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381
Oct ’24
Now Playing info error with CarPlay on iOS 18
Our app, Universalis (Apple ID 284942719) plays audio successfully on all versions of iOS up to and including iOS 17. It uses the old MediaPlayer interface because it is targeted at versions all the way down to iOS 12. On iOS 18, it plays audio but CarPlay fails to show the Now Playing screen. Instead, a message box pops up in CarPlay saying "There was a problem loading this content", with an OK button. Nevertheless the audio plays correctly. This has been reported in the wild by a user of iOS 18 with CarPlay. I am also able to reproduce it locally, running the app in Xcode with the CarPlay Simulator, with an iPhone using iOS 18.0 or iOS 18.1. Earlier versions work correctly. Looking at the console log in CarPlay, the following error message appears about 10 seconds before the error message pops up: MSVEntitlementUtilities - Process Universalis PID[1173] - Group: (null) - Entitlement: com.apple.mediaremote.external-artwork-validation - Entitled: NO - Error: (null) The message has an orange background which appears to mean that it does not come directly from NSLog in the app. The message appears immediately after the request handler of MPMediaItemArtwork has been called requesting a 128 x 128 image and has successfully returned a 128x128 UIImage object. This has been reported through Feedback Assistant: Bug report ID is FB15343941 How can we work round this error?
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1.2k
Oct ’24
AVAssetWriterInput -- inserting sample buffers with pauses in between not working
Hi, I'm trying to insert CMSampleBuffers into an AVAssetWriterInput that has been configured with expectsMediaDataInRealTime = false with pauses. That is, I insert fixed-length audio at specific (increasing and non-overlapping) time points with large gaps in between. E.g., 5 seconds of audio at t=3.0, 5 seconds of audio at t=12.0, etc. The first audio sample plays at t=3 in the final output video as expected. But then all the other samples are bunched up immediately after it instead of being scheduled at the correct time. Below is my code. I'm just loading the asset and then readjusting its timestamps to be correct in the absolute timeline. Why do they not get scheduled correctly when the timestamps and durations are definitely correct and non-overlapping? func addFrame(_ pixelBuffer: CVPixelBuffer) { guard CGSize(width: pixelBuffer.width, height: pixelBuffer.height) == outputSize else { return } let frameTime = CMTimeMake(value: frameCount, timescale: frameRate) if videoInput?.isReadyForMoreMediaData == true { pixelBufferAdaptor?.append(pixelBuffer, withPresentationTime: frameTime) frameCount += 1 currentTime = frameTime } } func addMP3AudioClip(_ audioData: Data) async throws { let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString + ".mp3") defer { try? FileManager.default.removeItem(at: tempURL) } try audioData.write(to: tempURL) let asset = AVAsset(url: tempURL) let duration = try await asset.load(.duration) let audioTrack = try await asset.loadTracks(withMediaType: .audio).first! let audioReader = try AVAssetReader(asset: asset) let outputSettings: [String: Any] = [ AVFormatIDKey: kAudioFormatLinearPCM, AVSampleRateKey: 44100, AVNumberOfChannelsKey: 2, AVLinearPCMBitDepthKey: 16, AVLinearPCMIsFloatKey: false, AVLinearPCMIsBigEndianKey: false, AVLinearPCMIsNonInterleaved: false ] let audioReaderOutput = AVAssetReaderTrackOutput(track: audioTrack, outputSettings: outputSettings) audioReader.add(audioReaderOutput) guard audioReader.startReading() else { throw NSError(domain: "AudioReaderError", code: 0, userInfo: [NSLocalizedDescriptionKey: "Failed to start reading audio"]) } let baseInsertionTime = currentTime.convertScale(duration.timescale, method: .default) // Capture the current video time when the method is called print("Adding audio clip at \(baseInsertionTime.seconds) seconds, duration: \(duration.seconds) seconds") var audioTime = CMTime.zero var totalDuration: Double = 0 while let sampleBuffer = audioReaderOutput.copyNextSampleBuffer() { let bufferDuration = CMSampleBufferGetDuration(sampleBuffer) let adjustedBuffer = adjustTimeStamp(of: sampleBuffer, by: baseInsertionTime) while !audioInput!.isReadyForMoreMediaData { try await Task.sleep(nanoseconds: 100_000_000) // 0.1 second } audioInput!.append(adjustedBuffer) print(" Adjusted time: \(adjustedBuffer.presentationTimeStamp.seconds)") audioTime = CMTimeAdd(audioTime, bufferDuration) totalDuration += bufferDuration.seconds } print("Finished adding audio clip. Last sample at: \(CMTimeAdd(baseInsertionTime, audioTime).seconds) seconds") print(" totalDuration=\(totalDuration)") } private func adjustTimeStamp(of sampleBuffer: CMSampleBuffer, by timeOffset: CMTime) -> CMSampleBuffer { var count: CMItemCount = 0 CMSampleBufferGetSampleTimingInfoArray(sampleBuffer, entryCount: 0, arrayToFill: nil, entriesNeededOut: &count) var timingInfo = [CMSampleTimingInfo](repeating: CMSampleTimingInfo(), count: count) CMSampleBufferGetSampleTimingInfoArray(sampleBuffer, entryCount: count, arrayToFill: &timingInfo, entriesNeededOut: nil) for i in 0..<count { timingInfo[i].presentationTimeStamp = CMTimeAdd(timingInfo[i].presentationTimeStamp, timeOffset) if timingInfo[i].decodeTimeStamp != .invalid { timingInfo[i].decodeTimeStamp = CMTimeAdd(timingInfo[i].decodeTimeStamp, timeOffset) } else { timingInfo[i].decodeTimeStamp = timingInfo[i].presentationTimeStamp } } var adjustedBuffer: CMSampleBuffer? CMSampleBufferCreateCopyWithNewTiming(allocator: nil, sampleBuffer: sampleBuffer, sampleTimingEntryCount: count, sampleTimingArray: &timingInfo, sampleBufferOut: &adjustedBuffer) return adjustedBuffer! }
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537
Oct ’24
CMSAMPLEBuffer: audio PCM to MP4 AAC
Hello, As explained in this link, the AVAssetReaderTrackOutput.copyNextSampleBuffer() returns a CMSampleBuffer in linear PCM audio format. I want to place this audio buffer into an AVAssetWriterInput of type kAudioFormatMPEG4AAC, but I can't manage the conversion. Could you help me by providing an extension that returns a CMSampleBuffer converted from linear PCM audio format to kAudioFormatMPEG4AAC? Example: extension CMSampleBuffer { func fromPCMToAAC() -> CMSampleBuffer? { // Here, get a new AudioStreamBasicDescription, create a CMSampleBuffer and a CMBlockBuffer } } I've tried multiple times but without success. Software: iOS 18.1 XCode: 16.0 Thank you!
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775
Oct ’24
Glitch in AVPlayer while playing HLS videos
We have observed consistent glitches in video playback when using AVPlayer to stream HLS (HTTP Live Streaming) videos on iOS. The issue manifests as intermittent frame drops, stuttering, and playback instability during HLS streams. However, the same behavior is not present when playing MP4 videos using the same AVPlayer instance. The HLS streams being used follow standard encoding practices, and network conditions have been ruled out as a cause for this problem. https://drive.google.com/file/d/1lhdpHTyjPYCYLHjzvb6ZF6P6jehIuwY0/view?usp=sharing Steps to Reproduce: 1. Load an HLS video into AVPlayer and initiate playback. 2. Observe intermittent glitches and stuttering during video playback. 3. Load and play an MP4 video in the same AVPlayer instance. 4. Notice that MP4 playback is smooth without any glitches.
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636
Oct ’24
Destination Video Sample
I have using the Destination Video sample project as a template to recreate a similar project. I have been able to update all text and images but when I go to change out the videos, it still plays the old videos. If I rename the new video to the old video name, the new video appears. Problem is, there are only two videos that repeat on different links. But changing the URLs in SampleData.swift to the new file path does not work. Any suggestions on how to replace a video with a newly imported asset? Here is an example of the code. Video( id: 1, name: "Landing", synopsis: """ After a long journey through the stars, the robot botanist and its trusty spaceship finally arrive at Wolf 1069 B, ready to explore the mysteries that lie on the planet’s surface. New plants to catalog, new animals to discover, and cool rocks to unearth. Follow along as the botanist’s mission begins! """, categoryIDs: [ 1004, 1005 ], url: URL(string: "file://BOT-anist_video.mov")!, imageName: "landing", yearOfRelease: 2024, duration: 66, contentRating: "NR", isFeatured: true ),
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446
Oct ’24
PHPickerViewControllerDelegate didCancel
Hello. In my app I have selection of photos and videos and also selection of PDF So I use PHPickerViewController for picking photos and videos and UIDocumentPickerViewController for picking documents. I found out that there's not documentPickerWasCancelled in PHPickerViewController delegate. So when a user presses Cancel, delegate's picker function fires the dialog is dismissed and system return a selected value of nil. But when I swipe the dialog down no event is generated so in my app I can't understand whether a user selected a photo or cancelled the dialog. In UIDocumentPickerViewController there's no such problems as it have didCancel as a separate funciton Is there any way to bypass this this?
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378
Oct ’24
'You don’t have permission. - The AVPlayerItem instance has failed with the error code 257 and domain "NSCocoaErrorDomain".'
[[PHImageManager defaultManager] requestAVAssetForVideo:asset options:videoOptions resultHandler:^(AVAsset *_Nullable avAsset, AVAudioMix *_Nullable audioMix, NSDictionary *_Nullable info) { if ([avAsset isKindOfClass:[AVURLAsset class]]) { AVURLAsset *urlAsset = (AVURLAsset *)avAsset; NSURL *videoURL = urlAsset.URL; mediaInfo[@"path"] = videoURL.absoluteString; } else { // Failed to get video asset completion(nil); } }];``` Before iOS 18, i could able access AVAsset video using the method mentioned above with the url, but starting from the iOS 18 version, the following error appears 'You don’t have permission. - The AVPlayerItem instance has failed with the error code 257 and domain "NSCocoaErrorDomain".'
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705
Oct ’24
Sound quality
Am a musician/DJ. Jumped from 14 Pro Max iOS 17 to 16 Pro Max iOS 18.1 b4. For each audio source(music app/yt music etc.) same track/eq/volume compared side by side. With the new device, overall it's a bit muffled and damping music when highs and lows are mixed. Most noticeable when listening to high vocals and acoustic instruments. Drum and bass sound much like on an old Nokia. On 14 Pro it's nothing like that. Thank you
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477
Oct ’24
While AirPlaying, MPVolumeView snaps to different volume when I play my app media
I have an app that plays sound files stored locally. I'm using a single SwiftUI view with a MPVolumeView so the user can control system volume from the player in my app. When I'm playing the sound file on the iPhone, my volume slider operates as expected. When I AirPlay to my AppleTV, the volume slider still works to control the volume, but when I hit play in my app, the volume snaps to a different value, but actual sound volume doesn't change. Control still works. Flipping to control center, I see a volume mismatch between system volume and the MPVolumeView. Here's the code that I use to put the slider in my app. struct VolumeSlider: UIViewRepresentable { func makeUIView(context: Context) -> MPVolumeView { let vv = MPVolumeView(frame: .zero) vv.showsVolumeSlider = true vv.setVolumeThumbImage(UIImage() ,for: UIControl.State.normal) return vv } func updateUIView(_ uiView: MPVolumeView, context: Context) { // No need to update the view in this case } } I'm using AVFoundation and AVAudioPlayer to playback the sound file. I'm using MediaPlayer to tell MPNowPlayingInfoCenter the track info and AlbumArt. Audio control via control center works perfectly. Does the same if I target iOS 16 or 17. Is this a bug with the MPVolumeView or the way I added it to the app?
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738
Oct ’24
Issue with Low-Latency HLS Playback Using AVAssetResourceLoaderDelegate
Hi, I am writing to seek any help or workaround regarding an issue I have encountered while implementing Low-Latency HLS playback using the AVAssetResourceLoaderDelegate. I have been successfully loading playlists during HLS live playback using the AVAssetResourceLoaderDelegate. However, after introducing Low-Latency HLS, I have run into a problem. When the AVPlayer loads low-latency content playback natively, everything works fine. But when I use the delegate for loading, I encounter the following error from AVPlayer's status observer: CoreMediaErrorDomain -15410 Low Latency: Server must support http2 ECN and SACK It seems there is no problem since playback does not stop, but there is a very critical part missing. The playback does not achieve the expected low latency and behaves similarly to standard HLS. Additionally, this behavior only occurs on iOS 16 devices and simulators. On iOS 17 simulators and devices, the error message does not appear, and the latency remains low as expected. Therefore, I suspect that there might be some misjudgment in the verification process within the internal implementation of AVPlayer. Since our app needs to support iOS 16, I would appreciate any solutions, methods to try, or workarounds that you could share regarding this issue. Thank you.
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808
Oct ’24
SoundRecognition causes Input/Output callbacks to have varying Buffer sizes and introduces Glitching
Hello, We have noticed an issue with SoundRecognition that causes glitching with our AudioUnit setup in Smule. Input and output frame sizes are inconsistent. Input frame size does not match [AVAudioSession sharedInstance].IOBufferDuration My best guess is that SoundRecognition influences the input frame size and not the output frame size. To reproduce use the example app here: https://github.com/MarkoGill/SoundRecognitionBug Hardware/OS iPhone 14 Pro on iOS 18 -> Experiences the problem iPhone 11 on iOS 18 -> Experiences the problem iPhone 15 on iOS 18 -> Not experiencing the problem Reproduction Steps Enable Sound Recognition (Settings > Accessibility > Sound Recognition > On) Enable a Sound for detection (Sounds > Dog > On) Open the example app with headset (it routes input to output) Notice glitching occurs Check the logs. Record and Playback buffer sizes vary Example Log: AU input sample rate: 48000.000000 AU output sample rate: 48000.000000 hardware sample rate: 48000.000000 hardware buffer size: 1104.000000 updated record frame counts: 1024 updated playback frame counts: 1104 Notes: You can disable Sound Recognition, restart the app, and playback behaves correctly.
4
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992
Oct ’24
iOS18 Apple Car Play Audio Error
After updating iOS18.1 Beta Version, I have a lot of issues with my Apple Car Play as per following. Audio Quality Really Bad (it’s not playing with media instead voice channel. Sometime, it’s playing with the phone speakers even though I have connected the car play via cable. Its not operating well with car steering control such as Volume up & down, skip button. After receiving the phone call, it’s go back to the original audio quality but when my phone screen locked, its go bad again. I expect to fix these problems asap as I love to play music when I drive around.
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441
Oct ’24
Toggling AVMusicTrack isMuted
Hi! I have an AVAudioSequencer with some AVMusicTracks that are filled with AVParameterEvents. If I toggle the isMuted property of a track, it will instantly mute when changed to true. However, after turning the muting to false, the events will only triggers on the next round of a loop and not instantly. Is this intended behaviour, and is there some way to get the events to trigger immediately after toggling the isMuted to be false?
2
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631
Oct ’24
What causes "issue_type = overload" in coreaudiod with USB audio interface?
I have a USB audio interface that is causing kernel traps and the audio output to "skip" or dropout every few seconds. This behavior occurs with a completely fresh install of Catalina as well as Big Sur with the stock Music app on a 2019 MacBook Pro 16 (full specs below). The Console logs show coreaudiod got an error from a kernel trap, a "USB Sound assertion" in AppleUSBAudio/AppleUSBAudio-401.4/KEXT/AppleUSBAudioDevice.cpp at line 6644, and the Music app "skipping cycle due to overload." I've added a short snippet from Console logs around the time of the audio skip/drop out. The more complete logs are at this gist: https://gist.github.com/djflux/08d9007e2146884e6df1741770de5105 I've also opened a Feedback Assistant ticket (FB9037528): https://feedbackassistant.apple.com/feedback/9037528 Does anyone know what could be causing this issue? Thanks for any help. Cheers, Flux aka Andy. Hardware Overview:  Model Name: MacBook Pro  Model Identifier: MacBookPro16,1  Processor Name: 8-Core Intel Core i9  Processor Speed: 2.4 GHz  Number of Processors: 1  Total Number of Cores: 8  L2 Cache (per Core): 256 KB  L3 Cache: 16 MB  Hyper-Threading Technology: Enabled  Memory: 64 GB  System Firmware Version: 1554.80.3.0.0 (iBridge: 18.16.14347.0.0,0) System Software Overview: System Version: macOS 11.2.3 (20D91)  Kernel Version: Darwin 20.3.0  Boot Volume: Macintosh HD  Boot Mode: Normal  Computer Name: mycomputername  User Name: myusername  Secure Virtual Memory: Enabled  System Integrity Protection: Enabled USB interface: Denon DJ DS1 Snippet of Console logs error 21:07:04.848721-0500 coreaudiod HALS_IOA1Engine::EndWriting: got an error from the kernel trap, Error: 0xE00002D7 default 21:07:04.848855-0500 Music HALC_ProxyIOContext::IOWorkLoop: skipping cycle due to overload default 21:07:04.857903-0500 kernel USB Sound assertion (Resetting engine due to error returned in Read Handler) in /AppleInternal/BuildRoot/Library/Caches/com.apple.xbs/Sources/AppleUSBAudio/AppleUSBAudio-401.4/KEXT/AppleUSBAudioDevice.cpp at line 6644 ... default 21:07:05.102746-0500 coreaudiod Audio IO Overload inputs: 'private' outputs: 'private' cause: 'Unknown' prewarming: no recovering: no default 21:07:05.102926-0500 coreaudiod   CAReportingClient.mm:508  message {   HostApplicationDisplayID = "com.apple.Music";   cause = Unknown;   deadline = 2615019;   "input_device_source_list" = Unknown;   "input_device_transport_list" = USB;   "input_device_uid_list" = "AppleUSBAudioEngine:Denon DJ:DS1:000:1,2";   "io_buffer_size" = 512;   "io_cycle" = 1;   "is_prewarming" = 0;   "is_recovering" = 0;   "issue_type" = overload;   lateness = "-535";   "output_device_source_list" = Unknown;   "output_device_transport_list" = USB;   "output_device_uid_list" = "AppleUSBAudioEngine:Denon DJ:DS1:000:1,2"; }: (null)
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21k
Oct ’24
Accessing Events from Video Device
I have an intra-**** video device that's supported by Apple's AVCaptureDevice. I can use the AV classes to connect to the device and get video. However, this device has a button that's used to acquire still images from the video stream. I can't use the IOUSBDeviceInterface to do an asynchronous read, because the Apple driver has the device opened exclusively. How do I go about receiving the button event in this scenario? I know which pipe to read, based on a bus analyzer when I run this on Windows, I just need to know how to access that pipe when the device is opened by another process.
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625
Oct ’24