I recently installed a rear-view camera in my car, and ever since, I've been experiencing a frustrating issue with my CarPlay. After about 15 seconds of playing audio via Bluetooth, the sound stops coming out of the speakers, even though the song continues to run in the background.
For context, my stereo system is an aftermarket unit that I installed to enable CarPlay functionality. Everything worked perfectly before adding the rear-view camera. Unfortunately, my unit does not have a port for a wired connection, so I can't test the audio using a cable.
Has anyone experienced a similar issue? Could the camera installation be interfering with the Bluetooth or audio system somehow? Any advice or troubleshooting tips would be greatly appreciated!
Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.
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Hi,
On macOS Sonoma and earlier versions, I used my script along with a LaunchDaemon to continuously record my screen.
However, after upgrading to macOS Sequoia, the LaunchDaemon no longer works for screen recording. It only works when I use a LaunchAgent.
For my workflow, using a LaunchDaemon and running the ffmpeg process as root is much more efficient than running it as a regular user. Does anyone know how to run a script in the background using a LaunchDaemon on macOS Sequoia?
Here are my LaunchDaemon plist and script:
LaunchDaemon plist:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key> <string>local.ScreenRecord</string>
<key>Disabled</key> <false/>
<key>RunAtLoad</key> <true/>
<key>KeepAlive</key> <true/>
<key>Nice</key>
<integer>-20</integer>
<key>ProgramArguments</key>
<array>
<string>/bin/bash</string>
<string>/usr/local/distrib/record.bash</string>
</array>
</dict>
</plist>
Script
## !!! START CONFIGURATION !!!
#
FFMPEG_LOC="/usr/local/distrib/ffmpeg"
FFMPEG_INPUT="-hide_banner -f avfoundation -capture_cursor 1 -pixel_format uyvy422"
FFMPEG_VSET="-codec libx264 -r 22 -crf 26 -preset veryfast -b:v 5M -maxrate 7M -bufsize 14M"
TIME_REC="-t 600"
FOLDER_REC="/usr/local/distrib/REC/"
#
## !!! END CONFIGURATION !!!
#
# Find number id monitor
MON_ID=$($FFMPEG_LOC -hide_banner -f avfoundation -list_devices true -i "" 2>&1 | awk -F'[]|[]' '/Capture\ screen/ {print $4}')
#
if [ -n "$MON_ID" ]
then
# Time for name
DATE_REC=$(date +"%m-%d-%Y_%H-%M-%S")
# Number of output video file
OUTPUT_NUM=0
# Full command to record
FFMPEG_FULL_COMMAND=""
for MON_NUM in $MON_ID
do
FFMPEG_FULL_COMMAND=""$FFMPEG_FULL_COMMAND" "$FFMPEG_INPUT" -i "$MON_NUM" "$FFMPEG_VSET" "$TIME_REC" -map "$OUTPUT_NUM" "$FOLDER_REC""$DATE_REC"_Mon"$MON_NUM".mkv"
let OUTPUT_NUM=$OUTPUT_NUM+1
done
$FFMPEG_LOC $FFMPEG_FULL_COMMAND
else
echo "No monitors"
sleep 5
fi
Overlay changes color in HDR video When I’m using trying to add an overlay to an image with AVMutableVideoComposition, When the video is in HDR the overlay colors are changing and white becomes grey screen shot from original HDR video result from the code with the wrong overlay colorthe result when reducing to SDR (the right overlay color)
the distorted colorsthe way it should look(sdr)
Im creating the overlay with a CGContext
class CustomHdrCompositor: NSObject, AVVideoCompositing {
private let coreImageContext = CIContext(options: [CIContextOption.cacheIntermediates: false])
let combinedFilter = CIFilter(name: "CISourceOverCompositing")!
var sourcePixelBufferAttributes: [String: Any]? = [String(kCVPixelBufferPixelFormatTypeKey): [kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange]]
var requiredPixelBufferAttributesForRenderContext: [String: Any] =
[String(kCVPixelBufferPixelFormatTypeKey): [kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange]]
var supportsWideColorSourceFrames = true
var supportsHDRSourceFrames = true
func renderContextChanged(_ newRenderContext: AVVideoCompositionRenderContext) {
return
}
func startRequest(_ request: AVAsynchronousVideoCompositionRequest) {
guard let outputPixelBuffer = request.renderContext.newPixelBuffer() else {
print("No valid pixel buffer found. Returning.")
request.finish(with: CustomCompositorError.ciFilterFailedToProduceOutputImage)
return
}
guard let requiredTrackIDs = request.videoCompositionInstruction.requiredSourceTrackIDs, !requiredTrackIDs.isEmpty else {
print("No valid track IDs found in composition instruction.")
return
}
let sourceCount = requiredTrackIDs.count
if sourceCount > 1 {
request.finish(with: CustomCompositorError.notSupportingMoreThanOneSources)
return
}
if sourceCount == 1 {
let sourceID = requiredTrackIDs[0]
let sourceBuffer = request.sourceFrame(byTrackID: sourceID.value(of: Int32.self)!)!
let sourceCIImage = CIImage(cvPixelBuffer: sourceBuffer)
var textImage = TextLayerPlayer.instance.getTextLayerAtTimesStamp(ts:request.compositionTime.seconds)
combinedFilter.setValue(textImage, forKey: "inputImage")
if let outputImage = combinedFilter.outputImage {
let renderDestination = CIRenderDestination(pixelBuffer: outputPixelBuffer)
do {
try coreImageContext.startTask(toRender: outputImage, to: renderDestination)
} catch {
}
}
}
request.finish(withComposedVideoFrame: outputPixelBuffer)
}
}
func regularCompositionHdr(asset: AVAsset) -> AVVideoComposition
{
self.isHdr = checkHdr(asset: asset)
let avComposition = AVMutableComposition()
let composition = AVMutableVideoComposition()
composition.colorPrimaries = AVVideoColorPrimaries_ITU_R_2020
composition.colorTransferFunction = AVVideoTransferFunction_ITU_R_2100_HLG
composition.colorYCbCrMatrix = AVVideoYCbCrMatrix_ITU_R_2020
composition.renderSize = assetSize
composition.frameDuration = CMTime(value: 1, timescale: 30)
composition.customVideoCompositorClass = CustomHdrCompositor.self
composition.perFrameHDRDisplayMetadataPolicy = .propagate
return composition
}
I’m using this function to transfer the transparent CGImage to CIImage that supports HDR
func convertToHDRCIImage(from cgImage: CGImage,
maxBrightness: CGFloat = 3.0) -> CIImage? {
// Create a CIImage from the input CGImage
let baseImage = CIImage(cgImage: cgImage)
// Create HDR color adjustment filter
let colorAdjust = CIFilter(name: "CIColorMatrix")!
colorAdjust.setValue(baseImage, forKey: kCIInputImageKey)
// Calculate HDR multipliers based on maxBrightness
// This will maintain color ratios while increasing brightness
colorAdjust.setValue(CIVector(x: maxBrightness, y: 0, z: 0, w: 0), forKey: "inputRVector")
colorAdjust.setValue(CIVector(x: 0, y: maxBrightness, z: 0, w: 0), forKey: "inputGVector")
colorAdjust.setValue(CIVector(x: 0, y: 0, z: maxBrightness, w: 0), forKey: "inputBVector")
// Maintain alpha channel
colorAdjust.setValue(CIVector(x: 0, y: 0, z: 0, w: 1), forKey: "inputAVector")
guard let adjustedImage = colorAdjust.outputImage else {
return nil
}
// Apply color space transformation using CIImage's colorSpace property
let transformedImage = adjustedImage.matchedFromWorkingSpace(to: hdrWorkingSpace)!
// Create context with HDR color space
let context = CIContext(options: [
.workingColorSpace: hdrColorSpace,
.outputColorSpace: hdrColorSpace
])
// Get the image bounds
let bounds = transformedImage.extent
// Create a new pixel buffer with HDR format
var pixelBuffer: CVPixelBuffer?
let pixelBufferAttributes = [
kCVPixelBufferPixelFormatTypeKey: kCVPixelFormatType_64RGBAHalf,
kCVPixelBufferMetalCompatibilityKey: true
] as CFDictionary
CVPixelBufferCreate(kCFAllocatorDefault,
Int(bounds.width),
Int(bounds.height),
kCVPixelFormatType_64RGBAHalf,
pixelBufferAttributes,
&pixelBuffer)
guard let destinationBuffer = pixelBuffer else {
return nil
}
context.render(transformedImage,
to: destinationBuffer,
bounds: bounds,
colorSpace: hdrColorSpace)
// Create final CIImage from the HDR pixel buffer
let finalImage = CIImage(cvPixelBuffer: destinationBuffer,
options: [.colorSpace: hdrColorSpace])
return finalImage
}
When reducing the HDR to SDR it keeps the right color of the overlay with, but than it reduces the HDR effect which I want to keep
Topic:
Media Technologies
SubTopic:
Video
Hi all,
with my app ScreenFloat, you can record your screen, along with system- and microphone audio.
Those two audio feeds are recorded into separate audio tracks in order to individually remove or edit them later on.
Now, these recordings you create with ScreenFloat can be drag-and-dropped to other apps instantly. So far, so good, but some apps, like Slack, or VLC, or even websites like YouTube, do not play back multiple audio tracks, just one.
So what I'm trying to do is, on dragging the video recording file out of ScreenFloat, instantly baking together the two individual audio tracks into one, and offering that new file as the drag and drop file, so that all audio is played in the target app.
But it's slow. I mean, it's actually quite fast, but for drag and drop, it's slow.
My approach is this:
"Bake together" the two audio tracks into a one-track m4a audio file using AVMutableAudioMix and AVAssetExportSession
Take the video track, add the new audio file as an audio track to it, and render that out using AVAssetExportSession
For a quick benchmark, a 3'40'' movie, step 1 takes ~1.7 seconds, and step two adds another ~1.5 seconds, so we're at ~3.2 seconds. That's an eternity for a drag and drop, where the user might cancel if there's no immediate feedback.
I could also do it in one step, but then I couldn't use the AV*Passthrough preset, and that makes it take around 32 seconds then, because I assume it touches the video data (which is unnecessary in this case, so I think the two-step approach here is the fastest).
So, my question is, is there a faster way?
The best idea I can come up with right now is, when initially recording the screen with system- and microphone audio as separate tracks, to also record both of them into a third, muted, "hidden" track I could use later on, basically eliminating the need for step one and just ripping the two single audio tracks out of the movie and only have the video and the "hidden" track (then unmuted), but I'd still have a ~1.5 second delay there. Also, there's the processing and data overhead (basically doubling the movie's audio data).
All this would be great for an export operation (where one expects it to take a little time), but for a drag-and-drop operation, it's not ideal.
I've discarded the idea of doing a promise file drag, because many apps do not accept those, and I want to keep wide compatibility with all sorts of apps.
I'd appreciate any ideas or pointers.
Thank you kindly,
Matthias
Hello, Apple video engineers.
According to the official documentation, HLS is built on HTTP and traditionally ran on top of TCP. However, with the introduction of HTTP/3, which uses QUIC (runs on top of UDP), I would like to clarify the following:
Has the official HLS specification changed in a way that allows it to be considered UDP-based when using HTTP/3? And is it fair to say that HLS supports UDP since the transport can go over HTTP/3 and QUIC?
Would it be more accurate to say that HLS remains HTTP-dependent, and the transport protocol (TCP or QUIC) only determines how HTTP requests are delivered?
My thoughts: Since HTTP/3 uses QUIC running over UDP, we still can't say that HLS supports UDP in a classical way, as it is introduced in RTP, RTSP, SRT.
I have an app that records a health provider’s conversation with a patient. I am using Audio Queue Services for this. If a phone call comes in while recording, the doctor wants to be able to ignore the call and continue the conversation without touching the phone. If the doctor answers the call, that’s fine – I will stop the recording. I can detect when the call comes in and ends using CXCallObserver and AVAudioSession.interruptionNotification. Unfortunately, when a call comes in and before it is answered or dismissed, the audio is suppressed. After the call is dismissed, the audio continues to be suppressed. How can I continue to get audio from the mic as long as the user does not answer the phone call?
Topic:
Media Technologies
SubTopic:
Audio
Hi,
I'm working on an audio mixing app, that comes with bundled audio units that provide some of the app's core functionality.
For the next release of that app, we are planning to make two changes:
make the app sandboxed
package the bundled audio units as .appex bundles instead as .component bundles, so we don't need to take care of the installation at the correct spot in the file system
When trying this new approach, we run into problems where [[AVAudioUnitEffect alloc] initWithAudioComponentDescription:] crashes when trying to load our audio unit with the exception:
AVAEInternal.h:109 [AUInterface.mm:468:AUInterfaceBaseV3: (AudioComponentInstanceNew(comp, &_auv2)): error -10863
Our audio unit has the `sandboxSafe flag enabled, and loads fine when the host app is not sandboxed, so I'm guessing I got the bundle id/code signing requirements for the .appex correct.
It seems, that my .appex isn't even loaded, and the system rejects it because of its metadata. Maybe there something wrong the Info.plist generated by Juice?
"BuildMachineOSBuild" => "23H222"
"CFBundleDisplayName" => "elgato_sample_recorder"
"CFBundleExecutable" => "ElgatoSampleRecorder"
"CFBundleIdentifier" => "com.iwascoding.EffectLoader.samplerecorderAUv3"
"CFBundleName" => "elgato_sample_recorder"
"CFBundlePackageType" => "XPC!"
"CFBundleShortVersionString" => "1.0.0.0"
"CFBundleSignature" => "????"
"CFBundleSupportedPlatforms" => [
0 => "MacOSX"
]
"CFBundleVersion" => "1.0.0.0"
"DTCompiler" => "com.apple.compilers.llvm.clang.1_0"
"DTPlatformBuild" => "24C94"
"DTPlatformName" => "macosx"
"DTPlatformVersion" => "15.2"
"DTSDKBuild" => "24C94"
"DTSDKName" => "macosx15.2"
"DTXcode" => "1620"
"DTXcodeBuild" => "16C5032a"
"LSMinimumSystemVersion" => "10.13"
"NSExtension" => {
"NSExtensionAttributes" => {
"AudioComponents" => [
0 => {
"description" => "Elgato Sample Recorder"
"factoryFunction" => "elgato_sample_recorderAUFactoryAUv3"
"manufacturer" => "Manu"
"name" => "Elgato: Elgato Sample Recorder"
"sandboxSafe" => 1
"subtype" => "Znyk"
"tags" => [
0 => "Effects"
]
"type" => "aufx"
"version" => 65536
}
]
}
"NSExtensionPointIdentifier" => "com.apple.AudioUnit-UI"
"NSExtensionPrincipalClass" => "elgato_sample_recorderAUFactoryAUv3"
}
"NSHighResolutionCapable" => 1
}
Any ideas what I am missing?
I am work an app development on an app which request an audio function in background as an alert sound.
during debug testing , the function work fine,
but once I testing standalone without debugging , The function not work , it will play out the sound when I back to app.
does any way to trace the issues ?
I am creating an app that decodes H.265 elementary streams on iOS.
I use VideoToolBox to decode from H.265 to NV12.
The decoded data is enqueued in the CMSampleBufferDisplayLayer as a CMSampleBuffer.
However, nothing is displayed in the VideoPlayerView. It remains black.
The decoding in VideoToolBox is successful. I confirmed this by saving the NV12 data in the CMSampleBuffer to a file and displaying it using a tool.
Why is nothing displayed in the VideoPlayerView?
I can provide other source code as well.
//
// VideoPlayerView.swift
// H265Decoder
//
// Created by Kohshin Tokunaga on 2025/02/15.
//
import SwiftUI
import AVFoundation
struct VideoPlayerView: UIViewRepresentable {
// Return an H265Player as the coordinator, and start playback there.
func makeCoordinator() -> H265Player {
H265Player()
}
func makeUIView(context: Context) -> UIView {
let uiView = UIView(frame: .zero)
// Base layer for attaching sublayers
uiView.backgroundColor = .black // Screen background color (for iOS)
// Create the display layer and add it to uiView.layer
let displayLayer = context.coordinator.displayLayer
displayLayer.frame = uiView.bounds
displayLayer.backgroundColor = UIColor.clear.cgColor
uiView.layer.addSublayer(displayLayer)
// Start playback
context.coordinator.startPlayback()
return uiView
}
func updateUIView(_ uiView: UIView, context: Context) {
// Reset the frame of the AVSampleBufferDisplayLayer when the view's size changes.
let displayLayer = context.coordinator.displayLayer
displayLayer.frame = uiView.layer.bounds
// Optionally update the layer's background color, etc.
uiView.backgroundColor = .black
displayLayer.backgroundColor = UIColor.clear.cgColor
// Flush transactions if necessary
CATransaction.flush()
}
}
//
// H265Player.swift
// H265Decoder
//
// Created by Kohshin Tokunaga on 2025/02/15.
//
import Foundation
import AVFoundation
import CoreMedia
class H265Player: NSObject, VideoDecoderDelegate {
let displayLayer = AVSampleBufferDisplayLayer()
private var decoder: H265Decoder?
override init() {
super.init()
// Initial configuration for the display layer
displayLayer.videoGravity = .resizeAspect
// Initialize the decoder (delegate = self)
decoder = H265Decoder(delegate: self)
// For simple playback, set isBaseline to true
decoder?.isBaseline = true
}
func startPlayback() {
// Load the file "cars_320x240.h265"
guard let url = Bundle.main.url(forResource: "temp2", withExtension: "h265") else {
print("File not found")
return
}
do {
let data = try Data(contentsOf: url)
// Set FPS and video size as needed
let packet = VideoPacket(data: data,
type: .h265,
fps: 30,
videoSize: CGSize(width: 1080, height: 1920))
// Decode as a single packet
decoder?.decodeOnePacket(packet)
} catch {
print("Failed to load file: \(error)")
}
}
// MARK: - VideoDecoderDelegate
func decodeOutput(video: CMSampleBuffer) {
// When decoding is complete, send the output to AVSampleBufferDisplayLayer
displayLayer.enqueue(video)
}
func decodeOutput(error: DecodeError) {
print("Decoding error: \(error)")
}
}
Topic:
Media Technologies
SubTopic:
Video
The documentation of the Apple Music Feed API states that the Album object would include songs — a list of songs in the album. As per the doc, this would be an array of object Album.RelatedSong, which would include both an id and nameDefault.
Unfortunately, the album parquet files only include the song id and not the name of the song itself.
Please advise - is the documentation incorrect or are the recently posted parquet files in error?
Topic:
Media Technologies
SubTopic:
General
I have an iPad app that I want to run on Apple Silicon macs.
Everything works fine except for VNDocumentCameraViewController. According to the docs this class is available on:
iOS 13.0+ iPadOS 13.0+ Mac Catalyst 13.1+ visionOS 1.0+
yet when I try using it I get Document camera is not available on my Mac Studio running macOS 15.2
Is this expected behaviour?
Thanks
I’m spot-checking some of the data I’m extracting from the Apple Music Feed parquet files and finding numerous issues of invalid album IDs.
For example, just looking at any album with a primary artist id of 163043, I see a few albums that are not available at music.apple.com/us/album/NNN. These include:
981094158 - Time and the River
1803443737 - Celebration (Live New York ’80)
1525426873 - Anything You Want: The Warner-Reprise-Elektra Years
I notice that neither of these album ids are returned using the general Music API, so I’m a bit confused why they would exist in the parquet files at all.
Thanks.
Topic:
Media Technologies
SubTopic:
General
It's only occurs on iOS 18+. Backtrace attached below.
Exception Codes: 0x0000000000000000, 0x0000000000000000
Termination Reason: SIGNAL 6 Abort trap: 6
Terminating Process: NoteKeys [24384]
Triggered by Thread: 0
Last Exception Backtrace:
0 CoreFoundation 0x1a2d4c7cc __exceptionPreprocess + 164 (NSException.m:249)
1 libobjc.A.dylib 0x1a001f2e4 objc_exception_throw + 88 (objc-exception.mm:356)
2 CoreFoundation 0x1a2e47748 +[NSException raise:format:] + 128 (NSException.m:0)
3 AVFAudio 0x1bd41f4c8 -[AVMIDIPlayer play:] + 300 (AVMIDIPlayer.mm:145)
4 NoteKeys 0x1023c0670 SoundGenerator.playData() + 20 (SoundGenerator.swift:170)
5 NoteKeys 0x1023c0670 EditViewController.playBtnTapped(startIndex:) + 940 (EditViewController.swift:2034)
6 NoteKeys 0x1024497fc specialized Keyboard.playBtnTapped(sender:) + 1904 (Keyboard.swift:1249)
7 NoteKeys 0x10244631c Keyboard.playBtnTapped(sender:) + 4 (<compiler-generated>:0)
8 NoteKeys 0x10244631c @objc Keyboard.playBtnTapped(sender:) + 48
9 UIKitCore 0x1a58739cc -[UIApplication sendAction:to:from:forEvent:] + 100 (UIApplication.m:5816)
10 UIKitCore 0x1a58738a4 -[UIControl sendAction:to:forEvent:] + 112 (UIControl.m:942)
11 UIKitCore 0x1a58736f4 -[UIControl _sendActionsForEvents:withEvent:] + 324 (UIControl.m:1013)
12 UIKitCore 0x1a5fe8d8c -[UIButton _sendActionsForEvents:withEvent:] + 124 (UIButton.m:4198)
13 UIKitCore 0x1a5fea5a0 -[UIControl touchesEnded:withEvent:] + 400 (UIControl.m:692)
14 UIKitCore 0x1a57bb9ac -[UIWindow _sendTouchesForEvent:] + 852 (UIWindow.m:3318)
15 UIKitCore 0x1a57bb3d8 -[UIWindow sendEvent:] + 2964 (UIWindow.m:3641)
16 UIKitCore 0x1a564fb70 -[UIApplication sendEvent:] + 376 (UIApplication.m:12972)
17 UIKitCore 0x1a565009c __dispatchPreprocessedEventFromEventQueue + 1048 (UIEventDispatcher.m:2686)
18 UIKitCore 0x1a5659f3c __processEventQueue + 5696 (UIEventDispatcher.m:3044)
19 UIKitCore 0x1a5552c60 updateCycleEntry + 160 (UIEventDispatcher.m:133)
20 UIKitCore 0x1a55509d8 _UIUpdateSequenceRun + 84 (_UIUpdateSequence.mm:136)
21 UIKitCore 0x1a5550628 schedulerStepScheduledMainSection + 172 (_UIUpdateScheduler.m:1171)
22 UIKitCore 0x1a555159c runloopSourceCallback + 92 (_UIUpdateScheduler.m:1334)
23 CoreFoundation 0x1a2d20328 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 (CFRunLoop.c:1970)
24 CoreFoundation 0x1a2d202bc __CFRunLoopDoSource0 + 176 (CFRunLoop.c:2014)
25 CoreFoundation 0x1a2d1ddc0 __CFRunLoopDoSources0 + 244 (CFRunLoop.c:2051)
26 CoreFoundation 0x1a2d1cfbc __CFRunLoopRun + 840 (CFRunLoop.c:2969)
27 CoreFoundation 0x1a2d1c830 CFRunLoopRunSpecific + 588 (CFRunLoop.c:3434)
28 GraphicsServices 0x1eecfc1c4 GSEventRunModal + 164 (GSEvent.c:2196)
29 UIKitCore 0x1a5882eb0 -[UIApplication _run] + 816 (UIApplication.m:3844)
30 UIKitCore 0x1a59315b4 UIApplicationMain + 340 (UIApplication.m:5496)
31 NoteKeys 0x10254bc10 main + 68 (AppDelegate.swift:15)
32 dyld 0x1c870aec8 start + 2724 (dyldMain.cpp:1334)
Thanks very much for any help: )
Topic:
Media Technologies
SubTopic:
Audio
Hello,
I need to enumerate built-in media devices (cameras, microphones, etc.). For this purpose, I am using the CoreAudio and CoreMediaIO frameworks.
According to the table 'Daemon-Safe Frameworks' in Apple’s TN2083, CoreAudio is daemon-safe. However, the documentation does not mention CoreMediaIO.
Can CoreMediaIO be used in a daemon?
If not, are there any documented alternatives to detect built-in cameras in a daemon (e.g., via device classes in IOKit)?
Thank you in advance,
Pavel
Hi. I work on an audio app for iOS which is successfully using the MPRemoteCommandCenter for commands like next, back, skip forward, skip backward etc.
I am trying to implement playback rate controls in my app (so that users can change the playback speed of audio to 0.5x or 2x for example).
While the above commands work, the changePlaybackRateCommand does not seem to. I have enabled the command, given it a target/handler and set supported rates. With the other commands, this caused the UI to change on lock screen, in command center etc, by adding the control for the command (a next button for the next command for example). However, it does not seem to do anything for the playback rate command.
I can implement my own "rate button" UI and rate change handling, but I'm wondering if this is a known bug within Apple? Looking online, it seems other people face the same issue and haven't been able to get this command to work. Why is this API provided if it doesn't seem to do anything? Is there something I'm missing?
Kind regards.
Topic:
Media Technologies
SubTopic:
Audio
ApplicationMusicPlayer is not available on watchOS but all other platforms. Is there a technical reason for that like battery life? Same goes for SystemMusicPlayer and MPMusicPlayerController. I already filed feedbacks for that.
Hello!
I'm experiencing an issue with iOS's audio routing system when trying to use Bluetooth headphones for audio output while also recording environmental audio from the built-in microphone.
Desired behavior:
Play audio through Bluetooth headset (AirPods)
Record unprocessed environmental audio from the iPhone's built-in microphone
Actual behavior:
When explicitly selecting the built-in microphone, iOS reports it's using it (in currentRoute.inputs)
However, the actual audio data received is clearly still coming from the AirPods microphone
The audio is heavily processed with voice isolation/noise cancellation, removing environmental sounds
Environment Details
Device: iPhone 12 Pro Max
iOS Version: 18.4.1
Hardware: AirPods
Audio Framework: AVAudioEngine (also tried AudioQueue)
Code Attempted
I've tried multiple approaches to force the correct routing:
func configureAudioSession() {
let session = AVAudioSession.sharedInstance()
// Configure to allow Bluetooth output but use built-in mic
try? session.setCategory(.playAndRecord,
options: [.allowBluetoothA2DP, .defaultToSpeaker])
try? session.setActive(true)
// Explicitly select built-in microphone
if let inputs = session.availableInputs,
let builtInMic = inputs.first(where: { $0.portType == .builtInMic }) {
try? session.setPreferredInput(builtInMic)
print("Selected input: \(builtInMic.portName)")
}
// Log the current route
let route = session.currentRoute
print("Current input: \(route.inputs.first?.portName ?? "None")")
// Configure audio engine with native format
let inputNode = audioEngine.inputNode
let nativeFormat = inputNode.inputFormat(forBus: 0)
inputNode.installTap(onBus: 0, bufferSize: 1024, format: nativeFormat) { buffer, time in
// Process audio buffer
// Despite showing "Built-in Microphone" in route, audio appears to be
// coming from AirPods with voice isolation applied - welp!
}
try? audioEngine.start()
}
I've also tried various combinations of:
Different audio session modes (.default, .measurement, .voiceChat)
Different option combinations (with/without .allowBluetooth, .allowBluetoothA2DP)
Setting session.setPreferredInput() both before and after activation
Diagnostic Observations
When AirPods are connected:
AVAudioSession.currentRoute.inputs correctly shows "Built-in Microphone" after setPreferredInput()
The actual audio data received shows clear signs of AirPods' voice isolation processing
Background/environmental sounds are actively filtered out...
When recording a test audio played near the phone (not through the app), the recording is nearly silent. Only headset voice goes through.
Questions
Is there a workaround to force iOS to actually use the built-in microphone while maintaining Bluetooth output?
Are there any lower-level configurations that might resolve this issue?
Any insights, workarounds, or suggestions would be greatly appreciated. This is blocking a critical feature in my application that requires environmental audio recording while providing audio feedback through headphones 😅
Hello,
I'm trying to receive parquet files using the example that provided in documentation. I've done all required steps but receive constantly error 500 with "Upstream Service Error". By looking into the issues list, seems this error exists for months. Is it possible to get it working?
Hi. I am working on an audio app for iOS. I have implemented UI and handling which allows the user to change playback rate of audio. When the user selects a different rate, I update the rate property on my AVQueuePlayer. This is working well on device.
When I use Airplay, it works for some devices and not for others. Some devices won't change playback rate and will always play at 1x speed.
Is this possibly a limitation of those 3rd-party devices? Or is there something I'm missing/should check? Would love to get playback rate changes working across all Airplay devices with our app.
Kind regards.
I am currently developing an HEVC player using VideoToolbox on an iOS device.
I have successfully created an HEVC decoder that receives HEVC streams from our custom image capture and encoding device, and it can decode and display images properly.
However, when my image capture and encoding device configures the encoder to output HEVC streams with fragmented NALUs (i.e., an I-frame or P-frame is split and stored across multiple slice NALUs), the iOS decoder can be initialized successfully but fails to decode and output images.
Can VideoToolbox properly decode HEVC bitstreams when a single frame is split into multiple slice NALUs?
Key Observations:
1. Single-NALU frames work fine.
2. Multi-NALU frames (sliced I/P-frames) cause decoding failure.
3. The decoder session is created successfully (VTDecompressionSessionCreate returns no error).