We are currently working on a CarPlay navigation app and so far everything is working well except for speaking turn notifications.
Our TTS implementation works fine on the phone and works fine on CarPlay if the voice is spoken over the speaker in the car. If users connect a BT headset to the car and listen through that headset, then the voice commands are chopped up / stutter.
Why would users use BT headset? Well, we are working on a motorcycle app, and there are no speakers usually on a motorcycle.
It sounds like the BT channel is opened and closed repeatedly for every character / word spoken. This happens on different CarPlay devices and different Bluetooth headsets, we have reports from multiple users that they find this behavior annoying and that other apps work fine.
Is this a known issue? Are there possible workaround?
Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.
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We are encountering an issue where AVPlayer throws the error:
Error Domain=AVFoundationErrorDomain Code=-11819 "Cannot Complete Action" > Underlying Error Domain[(null)]:Code[0]:Desc[(null)]
This error seems to occur intermittently during video playback, especially after extended usage or when switching between different streams. We observe Error 11819 (AVFoundationErrorDomain) in Conviva platform that some of our users experience it but we couldn't reproduce it so far and we’re need support to determine the root cause and/or best practices to prevent it.
Some questions we have:
What typically triggers this error?
Could it be related to memory/resource constraints, network instability, or backgrounding?
Are there any recommended ways to handle or recover from this error gracefully?
Any insights or guidance would be greatly appreciated. Thanks!
Topic:
Media Technologies
SubTopic:
Streaming
I'm getting this error when I launch my application on the iPhone 14 Pro via Xcode. Everything builds OK. I"m using the audio kit plugin and Sound Pipe Audiokit.
The error starts as soon as I start the app and will carry on repeatedly.
I have background processing turned on as I'd like the sounds to play when the phone is locked via the headphones.
I can't find anything online about this error. None of my catches are printing anything in the logs either. So I don't know if this is just something that pops up repeatedly or whether there is something fundamentally wrong.
private func setupAudioSession() {
do {
let session = AVAudioSession.sharedInstance()
try session.setCategory(.playback, mode: .default, options: [.mixWithOthers])
try session.setActive(true, options: .notifyOthersOnDeactivation)
} catch {
errorMessage = "Failed to set up audio session: (error.localizedDescription)"
print(errorMessage ?? "")
}
}
// MARK: - Background Task Handling
private func setupBackgroundTaskHandling() {
// Handle app entering background
notificationObservers.append(
NotificationCenter.default.addObserver(
forName: UIApplication.didEnterBackgroundNotification,
object: nil,
queue: .main,
using: { [weak self] _ in
// Safely unwrap self
guard let self = self else { return }
self.handleBackgroundTransition()
}
)
)
I'm not sure if this is the code causing the issue. Any help would be gratefully appreciated. This is my first app I'm working on .
Topic:
Media Technologies
SubTopic:
Audio
I need to implement a solution through an API or custom driver to completely block out the built-in speakers and microphone of Mac, because I need other apps to use specified external devices as audio input and output. Is there a way to achieve this requirement? What I mean is that even in system preferences, it should not be possible to choose the built-in microphone and speakers; only my external device can be used.
When I play an m3u8 video using AVPlayer, it can play smoothly at 2x speed. However, when I set it to 3x speed, the playback is not smooth and there is no sound.
Topic:
Media Technologies
SubTopic:
Video
Hey everyone,
I'm encountering an issue with audio sample rate conversion that I'm hoping someone can help with. Here's the breakdown:
Issue Description:
I've installed a tap on an input device to convert audio to an optimal sample rate.
There's a converter node added on top of this setup.
The problem arises when joining Zoom or FaceTime calls—the converter gets deallocated from memory, causing the program to crash.
Symptoms:
The converter node is being deallocated during video calls.
The program crashes entirely when this happens.
Traditional methods of monitoring sample rate changes (tracking nominal or actual sample rates) aren't working as expected.
The Big Challenge:
I can't figure out how to properly monitor sample rate changes.
Listeners set up to track these changes don't trigger when the device joins a Zoom or FaceTime call.
Please, if anyone has experience with this or knows a solution, I'd really appreciate your help. Thanks in advance!
When I use musicKit SDK for Android 1.1.2, I found that MediaContainerType only defines three types:
NONE = 0;
ALBUM = 1;
PLAYLIST = 2;
The RADIO_STATION type is not defined.
However, the documentation of com.apple.android.music.playback.model states that the RADIO_STATION type is supported.
This problem causes an error after I pass in the stations ID:
MediaSessionManager com.apple.android.music.sdk.testapp D onPlaybackError() Quincy java.io.IOException
May I ask how to solve this problem?
我在使用 musicKit SDK for Android 1.1.2 时,发现 MediaContainerType 只定义了三种类型:
无 = 0;
专辑 = 1;
播放列表 = 2;
未定义 RADIO_STATION 类型。
但是,com.apple.android.music.playback.model 的文档指出支持 RADIO_STATION 类型。
此问题在我传入 stations ID 后会导致错误:
MediaSessionManager com.apple.android.music.sdk.testapp D onPlaybackError() Quincy java.io.IOException
请问如何解决这个问题?
Hello Apple Developer Community,
I am trying to play an HLS stream using the React Native Video player (underneath it's using AvPlayer). I am able to play the stream smoothly, but in some cases the player can not play the stream properly.
Behaviour:
react-native-video: I am getting the below error.
Error details from react-native-video player:
Error Code: -12971
Domain: CoreMediaErrorDomain
Localised Description: The operation couldn’t be completed. (CoreMediaErrorDomain error -12971.)
Target: 2457
The error does not provide a specific failure reason or recovery suggestion, which makes troubleshooting challenging.
AvPlayer on native iOS project: Video playback stopped after playing a few seconds.
AVPlayer configuration:
player.currentItem?.preferredForwardBufferDuration = 1
player.automaticallyWaitsToMinimizeStalling = true
N.B.: The same buffer duration is working perfectly for others.
Stream properties:
video resolution: 1280 x 720
I have attached an overview report generated from MediaStreamValidator.
I would appreciate any insights or suggestions on how to address this error. Has anyone in the community experienced a similar issue or have any advice on potential solutions?
Thank you for your help!
Environment→ ・Device: iPad 10th generation ・OS:**iOS18.3.2
I'm using AVAudioSession to record sound in my application. But I recently came to realize that when the app starts a recording session on a tablet, OS automatically sets the tablet volume to 50% and when after recording ends, it doesn't change back to the previous volume level before starting the recording. So I would like to know whether this is an OS default behavior or a bug?
If it's a default behavior, I much appreciate if I can get a link to the documentation.
Hello! I have been following the UsingAVFoundationToPlayAndPersistHTTPLiveStreams sample code in order to test persisting streams to disk. In addition to support for m3u8, I have noticed in testing that this also seems to work for MP3 Audio, simply by changing the plist entries to point to remote URLs with audio/mpeg content. Is this expected, or are there caveats that I should be aware of?
Thanks you!
I'm using an AVCaptureSession to send video and audio samples to an AVAssetWriter. When I play back the resultant video, sometimes there is a significant lag between the audio compared with the video, so they're just not in sync. But sometimes they are, with the same code.
If I look at the very first presentation time stamps of the buffers being sent to the delegate, via
func captureOutput(_: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection)
I see something like this:
Adding audio samples for pts time 227711.0855328798,
Adding video samples for pts time 227710.778785374
That is, the clock for audio vs video is behind: the first audio sample I receive is at 11.08 something, while the video video sample is earlier in time, at 10.778 something. The times are the presentation time stamps of the buffer, and the outputPresentationTimeStamp is the exact same number.
It feels like "video" vs the "audio" clock are just mismatched.
This doesn't always happen: sometimes they're synced. Sometimes they're not.
Any ideas? The device I'm recording is a webcam, on iPadOS, connected via the usb-c port.
I'm developing a tennis ball tracking feature using Vision Framework in Swift, specifically utilizing VNDetectedObjectObservation and VNTrackObjectRequest.
Occasionally (but not always), I receive the following runtime error:
Failed to perform SequenceRequest: Error Domain=com.apple.Vision Code=9 "Internal error: unexpected tracked object bounding box size" UserInfo={NSLocalizedDescription=Internal error: unexpected tracked object bounding box size}
From my investigation, I suspect the issue arises when the bounding box from the initial observation (VNDetectedObjectObservation) is too small. However, Apple's documentation doesn't clearly define the minimum bounding box size that's considered valid by VNTrackObjectRequest.
Could someone clarify:
What is the minimum acceptable bounding box width and height (normalized) that Vision Framework's VNTrackObjectRequest expects?
Is there any recommended practice or official guidance for bounding box size validation before creating a tracking request?
This information would be extremely helpful to reliably avoid this internal error.
Thank you!
Topic:
Media Technologies
SubTopic:
Photos & Camera
Tags:
ML Compute
Machine Learning
Camera
AVFoundation
I've got a problem with my app where I'm testing it on my own phone.
I'm using audio kit to generate tones as part of the app. Everything seems to work fine. Sounds start, Stop, etc. They play when the app is closed and when the phone is locked, so background is working.
However, I'm seeing an issue where, even when STOP is pressed and the application exited, if I get a notification such as a text message, the base tone for the app starts to play.
If I then open the app, check the Start/Stop button - it says start so that. hasnt' been activated. If I click Start, then a 2nd tone starts. This one stops with the Stop button. However the original tone that was set off by an incoming message carries on playing.
Until I go to the Open Apps View on the phone and slide the application upwards.
For the life of me, I can't figure out whats happening here.
I use the Apple Music API to poll my listening history at regular intervals.
Every morning between 5:30AM and 7:30AM, I observe a strange pattern in the API responses. During this window, one or more of the regular polling intervals returns a response that differs significantly from the prior history response, even though I had no listening activity at that time.
I'm using this endpoint: https://api.music.apple.com/v1/me/recent/played/tracks?types=songs,library-songs&include[library-songs]=catalog&include[songs]=albums,artists
Here’s a concrete example from this morning:
Time: 5:45AM
Fetch 1 Tracks (subset):
1799261990, 1739657416, 1786317143, 1784288789, 1743250261, 1738681804, 1789325498, 1743036755, ...
Time: 5:50AM
Fetch 2 Tracks (subset):
1799261990, 1739657416, 1786317143, 1623924746, 1635185172, 1574004238, 1198763630, 1621299055, ...
Time: 5:55AM
Fetch 3 Tracks (subset):
1799261990, 1739657416, 1786317143, 1784288789, 1743250261, 1738681804, 1789325498, 1743036755, ...
At 5:50, a materially different history is returned, then it returns back to the prior history at the next poll. I've listened to all of the tracks in each set, but the 5:50 history drops some tracks and returns some from further back in history.
I've connected other accounts and the behavior is consistent and repeatable every day across them. It appears the API is temporarily returning a different (possibly outdated or cached?) view of the user's history during that early morning window.
Has anyone seen this behavior before?
Is this a known issue with the Apple Music API or MusicKit backend? I'd love any insights into what might cause this, or recommendations on how to work around it.
The app registers a periodic time observer to the AVPlayer when the playback starts and it works fine. When switching to AirPlay during playback, the periodic time observation continues working as expected.
However, when switching back to local playback, the periodic time observer does not fire anymore until a seek is performed. The app removes the periodic time observer only when the playback stops.
I can see that when switching back to local playback, the timeControlStatus successively changes
to .waitingToPlayAtSpecifiedRate (reason: .evaluatingBufferingRate)
then to .waitingToPlayAtSpecifiedRate (reason: .toMinimizeStalls)
and finally to .playing
But the time observation does not work anymore.
Also, the issue is systematic with Live and VOD streams providing a program date (with HLS property #EXT-X-PROGRAM-DATE-TIME), with or without any DRM, and is never reproduced with other VOD streams.
Is it possible to stream video from a UVC (USB Video Class) camera on an iPhone 15? If so, are there any specific hardware or software requirements to enable this functionality?
Short summary
When setting exposureMode to .locked or .custom the brightness of a video stream still changes depending on the composition and contrast of the visible scene. These changes seem to come from contrast enhancements or dynamic range optimizations and totally break any analysis of the image that requires to assess absolute luminance. While exposure lock seems to indeed lock the physical exposure parameters of the camera (shutter speed and ISO), I cannot find any way to control these "soft" modifiers.
Details
Background
I am the developer of the app "phyphox", an educational app that makes the phone's sensors accessible to students as measurement tools in science experiments. Currently I am working on implementing photometric measurements through the camera and one very important aspect of it is luminance measurements.
This is particularly relevant since the light sensor of the phone has no publicly accessible API and the camera could to some extend make experiments available to Apple users that are otherwise only possible on Android devices.
Implementation
The app uses AVFoundation and explicitly picks individual cameras since camera groups do not support custom exposure settings. This means that it handles camera switching during zoom by itself and even implements its own auto exposure routines to optimize for the use in experiments. Therefore it always stays in custom exposure mode. The app uses YUV420 color space and the individual frames are analyzed in Metal using compute shaders.
However, the effects discussed here still occur if I remove all code to control the camera and replace it with a simple sequence of setting the exposure mode to custom, setting custom exposure values, setting a fixed white balance and then setting the exposure mode to locked as suggested on stackoverflow. This neither helps on an iPhone 14 Pro nor on an iPhone 8 despite a report on the developer forums that it would resolve the issue for older devices.
The app is open source, so the code can be seen in our current development branch (without the changes for the tests here, though) on github.
The videos below use the implementation with the suggestion from stackoverflow, but they can be reproduced in the same way with "professional" camera apps that promise manual control over the camera (like the Blackmagic cam to quote a reputable company) as well as the stock camera app after pressing and holding on the preview to enable AE/AF lock.
Demonstration
These examples were captured on an iPhone 14 Pro. The central part of the image (highlighted by the app using metal shaders after capture) should not change with fixed exposure settings, but significant changes are noticable if there are changes at the edge of the frame when I move a black piece of cardboard in from above:
https://share.icloud.com/photos/0b1f_3IB6yAQG-qSH27pm6oDQ
The graph above the camera preview is the average luminance (gamma corrected and weighted based on sRGB) across the highlighted central area and as mentioned before it should not change because of something happening at the side of the frame (worst case it should get a bit darker because of the cardboard's shadow).
In my opinion, the iPhone changes its mind on the ideal contrast as soon as it has a different exposure histogram because of the dark image part from the cardboard, but that's just me guessing.
For completeness here is the same effect in the stock camera app with AE/AF lock enabled:
https://share.icloud.com/photos/0cd7QM8ucBZKwPwE9mybnEowg
Here you can also see that the iPhone "ramps" the changes. The brightness of the gray area does not change immediately but transitions smoothly, so this is clearly deliberate postprocessing.
So...
Any suggestion on how to prevent this behavior would be highly appreciated.
I am developing a video streaming app for iPhone.
Minimum version is IOS 13.
I want to connect an external USB camera to the iPhone app and stream from it.
I have looked through a lot of information and have not found how to do this.
Is it possible to do this? Is there any documentation on this?
I have an AUv3 that passes all validation and can be loaded into Logic Pro without issue. The UI for the plug in can be any aspect ratio but Logic insists on presenting it in a view with a fixed aspect ratio. That is when resizing, both the height and width are resized. I have never managed to work out what it is I need to do specify to Logic to allow the user to resize width or height independently of each other.
Can anyone tell me what I need to specify in the AU code that will inform Logic that the view can be resized from any side of the window/panel?