Hello everyone,
I’m looking for more detailed information regarding UVC (USB Video Class) over MFi within the Apple ecosystem and would appreciate some clarification.
I’m interested in developing (or interfacing with) an accessory that transmits video over USB using the UVC standard, and I’d like to better understand how this works within the MFi (Made for iPhone) program.
Here are my main questions:
1. Do iOS devices provide native support for UVC over USB-C or Lightning within the MFi framework?
2. Are there any specific firmware or authentication requirements when the accessory is MFi-certified?
3. Does UVC support depend solely on the hardware interface (USB-C vs Lightning), or are there additional software-level requirements?
4. Is there any official documentation outlining the recommended flow for implementing UVC-based video capture accessories on iOS?
From what I understand, USB-C iPads appear to offer more direct support for standard UVC devices, but it’s not entirely clear how this integrates with the MFi ecosystem with iOS, especially for commercial product development.
If anyone has gone through this process or can point me to relevant technical documentation, I would greatly appreciate the guidance.
Thank you!
Video
RSS for tagDive into the world of video on Apple platforms, exploring ways to integrate video functionalities within your iOS,iPadOS, macOS, tvOS, visionOS or watchOS app.
Selecting any option will automatically load the page
Post
Replies
Boosts
Views
Activity
I read somewhere that the frames are returned in decode order instead of presentation order when using AVAssetReader. The documentation seems sparse on the subject. I have so far failed to find a video file where the frames are not returned in presentation order.
Can anyone confirm the frames are actually returned in decode order?
Hello,
Is there a way to handle 403 error returned by the server, eg token expired ?
Cannot find any information about this and everything that I tried wasn't working (addObserver, NotificationCenter with .AVPlayerItemNewErrorLogEntry, AVPlayerItemPlaybackStalled, ...)
Thank you very much.
Topic:
Media Technologies
SubTopic:
Video
Are serialized parameters already available inside -pluginInstanceAddedToDocument via FxParameterRetrievalAPI or are they being read later?
I have an app that has a WKWebView for watching YouTube videos. When the videos are windowed the audio seems fine, positionally as well. All perfectly.
When I fullscreen the video and it goes into the native visionOS video player the audio messes up.
It will suddenly sound like it is in your ears, or maybe even just one ear channel, or the position will be wrong. It might be fine for a moment but the second I touch the controls or move the window the sound jumps across the room, away from the window, or switches to stereo.
Sometimes exiting windows entirely you will still hear the videos playing. Even if you open the window back up and go to another screen and open another video, now you hear 2 videos playing at the same time with no way to stop the first one in the background, requiring to force restart the app.
It is all sorts of glitchy. I haven't the slightest clue what is happening here. I am strongly feeling this is a visionOS bug.
I tried using AVAudioSession to change some of the sound settings, and that makes zero difference in behavior.
Multiple testers have also reported this behavior and it has been seen on both visionOS 2.3 and 2.4 betas.
Thanks for the help! This is driving me mad! It is extremely consistent behavior!
I am working on a project for macOS where I am taking an AVCaptureSession's CVPixelBuffer and I need to convert it into a MTLTexture for rendering. On macOS the pixel format is 2vuy, there does not seem to be a clear format conversion while converting to a metal texture. I have been able to convert it to a texture but the color space seems to be off as it is rendering distorted colors with a double image.
I believe 2vuy is a single pane color space and I have tried to account for that, but I am unaware of what is off.
I have attached The CVPixelBuffer and The distorted MTLTexture along with a laundry list of errors.
On iOS my conversions are fine, it is only the macOS 2vuy pixel format that seems to have issues.
My code for the conversion is also attached.
If there are any suggestions or guidance on how to properly convert a 2vuy CVPixelBuffer to a MTLTexture I would greatly appreciate it.
Many Thanks
Conversion_Logs.txt
ConversionCode.swift
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
As of iOS 18, as far as I can tell, it appears there's still no AVPlayer options that allow users to toggle the caption / subtitle track on and off. Does anyone know of a way to do this with AVPlayer or with SwiftUI's VideoPlayer?
The following code reproduces this issue. It can be pasted into an app playground. This is a random video and a random vtt file I found on the internet.
import SwiftUI
import AVKit
import UIKit
struct ContentView: View {
private let video = URL(string: "https://server15700.contentdm.oclc.org/dmwebservices/index.php?q=dmGetStreamingFile/p15700coll2/15.mp4/byte/json")!
private let captions = URL(string: "https://gist.githubusercontent.com/samdutton/ca37f3adaf4e23679957b8083e061177/raw/e19399fbccbc069a2af4266e5120ae6bad62699a/sample.vtt")!
@State private var player: AVPlayer?
var body: some View {
VStack {
VideoPlayerView(player: player)
.frame(maxWidth: .infinity, maxHeight: 200)
}
.task {
// Captions won't work for some reason
player = try? await loadPlayer(video: video, captions: captions)
}
}
}
private struct VideoPlayerView: UIViewControllerRepresentable {
let player: AVPlayer?
func makeUIViewController(context: Context) -> AVPlayerViewController {
let controller = AVPlayerViewController()
controller.player = player
controller.modalPresentationStyle = .overFullScreen
return controller
}
func updateUIViewController(_ uiViewController: AVPlayerViewController, context: Context) {
uiViewController.player = player
}
}
private func loadPlayer(video: URL, captions: URL?) async throws -> AVPlayer {
let videoAsset = AVURLAsset(url: video)
let videoPlusSubtitles = AVMutableComposition()
try await videoPlusSubtitles.add(videoAsset, withMediaType: .video)
try await videoPlusSubtitles.add(videoAsset, withMediaType: .audio)
if let captions {
let captionAsset = AVURLAsset(url: captions)
// Must add as .text. .closedCaption and .subtitle don't work?
try await videoPlusSubtitles.add(captionAsset, withMediaType: .text)
}
return await AVPlayer(playerItem: AVPlayerItem(asset: videoPlusSubtitles))
}
private extension AVMutableComposition {
func add(_ asset: AVAsset, withMediaType mediaType: AVMediaType) async throws {
let duration = try await asset.load(.duration)
try await asset.loadTracks(withMediaType: mediaType).first.map { track in
let newTrack = self.addMutableTrack(withMediaType: mediaType, preferredTrackID: kCMPersistentTrackID_Invalid)
let range = CMTimeRangeMake(start: .zero, duration: duration)
try newTrack?.insertTimeRange(range, of: track, at: .zero)
}
}
}
How can I setup correctly AVSampleBufferDisplayLayer for video display when I have input picture format kCVPixelFormatType_32BGRA?
Currently video i visible in simulator, but not iPhone, miss I something?
Render code:
var pixelBuffer: CVPixelBuffer?
let attrs: [String: Any] = [
kCVPixelBufferPixelFormatTypeKey as String: kCVPixelFormatType_32BGRA,
kCVPixelBufferWidthKey as String: width,
kCVPixelBufferHeightKey as String: height,
kCVPixelBufferBytesPerRowAlignmentKey as String: width * 4,
kCVPixelBufferIOSurfacePropertiesKey as String: [:]
]
let status = CVPixelBufferCreateWithBytes(
nil,
width,
height,
kCVPixelFormatType_32BGRA,
img,
width * 4,
nil,
nil,
attrs as CFDictionary,
&pixelBuffer
)
guard status == kCVReturnSuccess, let pb = pixelBuffer else { return }
var formatDesc: CMVideoFormatDescription?
CMVideoFormatDescriptionCreateForImageBuffer(
allocator: nil,
imageBuffer: pb,
formatDescriptionOut: &formatDesc
)
guard let format = formatDesc else { return }
var timingInfo = CMSampleTimingInfo(
duration: .invalid,
presentationTimeStamp: currentTime,
decodeTimeStamp: .invalid
)
var sampleBuffer: CMSampleBuffer?
CMSampleBufferCreateForImageBuffer(
allocator: kCFAllocatorDefault,
imageBuffer: pb,
dataReady: true,
makeDataReadyCallback: nil,
refcon: nil,
formatDescription: format,
sampleTiming: &timingInfo,
sampleBufferOut: &sampleBuffer
)
if let sb = sampleBuffer {
if CMSampleBufferGetPresentationTimeStamp(sb) == .invalid {
print("Invalid video timestamp")
}
if (displayLayer.status == .failed) {
displayLayer.flush()
}
DispatchQueue.main.async { [weak self] in
guard let self = self else {
print("Lost reference to self drawing")
return
}
displayLayer.enqueue(sb)
}
frameIndex += 1
}
I have added some custom views on my pip. These controls disappeared after opening the camera in the Xcode16 environment and iOS 18 system, and it was found that these custom views were not removed and seemed to be obscured. They were displayed normally in the Xcode15.4 environment. I would like to ask how to make my custom views display normally
Topic:
Media Technologies
SubTopic:
Video
My app allows users to capture and save videos to the Photos app using the following Swift code:
PHPhotoLibrary.shared().performChanges {
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: fileURL)
} completionHandler: { success, error in
Videos are successfully saved to Photos and play correctly. However, users report that when they AirDrop these videos from the Photos app to another device (e.g., iPad to iPhone), the videos are saved in the Files app on the receiving device instead of the Photos app. This issue is more common with higher-resolution videos, such as 2K, recorded in HEVC format at 30 fps.
I wasn't able to reproduce the issue locally.
I've found a thread in public apple forum: https://discussions.apple.com/thread/255276865?sortBy=rank but I wonder maybe there are some special flags that I should clear or add to my videos (e.g. PHAssetChangeRequest)?
Thank you!
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).
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
Is there any way we can detect the status of the Show When Muted and Show on Skip Back device settings in code ?
In Final Cut Pro, keyframes for transform parameters (such as Position, Scale, and Rotation) are automatically set to “Smooth” interpolation. This often results in undesired easing between keyframes, especially when linear motion is required.
Currently, we have to manually adjust each keyframe to "Linear" using the Video Animation Editor, which can be time-consuming when working with many keyframes.
Would it be possible to add an option to set the default keyframe interpolation to "Linear"—either globally in Preferences or per parameter in the Inspector?
This would greatly streamline the animation workflow for many editors.
Thank you for considering this request!
I'm currently using ReplayKit for background screen recording, but I can't determine whether the screen is in landscape mode from the CMSampleBuffer. All other APIs for detecting screen orientation are foreground-based. What should I do?
I'm seeking to a specific sync frame in a video file (HEVC, recorded on iPad). When I feed the buffers from that sync frame on to VTDecompressionSession it consistently drops the 2.,3.,4. buffer with a kVTVideoDecoderReferenceMissingErr (or no error but no buffer on the simulator). If I feed all the buffers from the penultimate sync frame prior to the desired frame the buffers come out fine but that would just create a massive overhead to always do it. Tried multiple OS versions, devices etc. Seems a consistent problem.
Here's a sample project with the offending video (disregard memory handling etc):
https://github.com/marcuseckert/vtSample
I've filed a radar FB18228296 but would appreciate any feedback on circumventing or at least detecting this behavior prior to decoding.
Hello, I'm trying to subscribe to AVPlayerItem status updates using Combine and it's bridge to Swift Concurrency – .values.
This is my sample code.
struct ContentView: View {
@State var player: AVPlayer?
@State var loaded = false
var body: some View {
VStack {
if let player {
Text("loading status: \(loaded)")
Spacer()
VideoPlayer(player: player)
Button("Load") {
Task {
let item = AVPlayerItem(
url: URL(string: "https://sample-videos.com/video321/mp4/360/big_buck_bunny_360p_5mb.mp4")!
)
player.replaceCurrentItem(with: item)
let publisher = player.publisher(for: \.status)
for await status in publisher.values {
print(status.rawValue)
if status == .readyToPlay {
loaded = true
break
}
}
print("we are out")
}
}
}
else {
Text("No video selected")
}
}
.task {
player = AVPlayer()
}
}
}
After I click on the "load" button it prints out 0 (as the initial status of .unknown) and nothing after – even when the video is fully loaded.
At the same time this works as expected (loading status is set to true):
struct ContentView: View {
@State var player: AVPlayer?
@State var loaded = false
@State var cancellable: AnyCancellable?
var body: some View {
VStack {
if let player {
Text("loading status: \(loaded)")
Spacer()
VideoPlayer(player: player)
Button("Load") {
Task {
let item = AVPlayerItem(
url: URL(string: "https://sample-videos.com/video321/mp4/360/big_buck_bunny_360p_5mb.mp4")!
)
player.replaceCurrentItem(with: item)
let stream = AsyncStream { continuation in
cancellable = item.publisher(for: \.status)
.sink {
if $0 == .readyToPlay {
continuation.yield($0)
continuation.finish()
}
}
}
for await _ in stream {
loaded = true
cancellable?.cancel()
cancellable = nil
break
}
}
}
}
else {
Text("No video selected")
}
}
.task {
player = AVPlayer()
}
}
}
Is this a bug or something?
I'm working on a media app that would like to be able to tell if the TV connected to tvOS is running at 59.94hz or 60.00hz, so it can optimize a video stream. It looks like the best I can currently do is to check if the user has Match Content Rate enabled, and based on that, when calling displayManager.preferredDisplayCriteria to change video modes, I could guess which rate their TV might be in. It's not very ideal, because not all TVs support both of these rates, and my request for 59.94 might end up as 60 and vice versa.
I dug around and can't find any available method in UIScreen to get this info. The odd thing is, the data is right there in currentMode when I look in the debugger, but it seems to be in a private or undocumented class. Is there any way to get at it?
I'm developing a Final Cut Pro X workflow extension that transcribes audio and creates a text output. I need to allow users to drag this text directly from my extension into FCPX's timeline as titles.
Current Implementation:
Using NSFilePromiseProvider as per Apple's guidelines for drag and drop
Generating valid FCPXML (v1.10) with proper structure:
Complete resources section with format and asset references
Event and project hierarchy
Asset clip with connected title elements
Proper timing and duration calculations
Supporting multiple pasteboard types:
com.apple.finalcutpro.xml.v1-10
com.apple.finalcutpro.xml.v1-9
com.apple.finalcutpro.xml
What's Working:
Drag operation initiates correctly
File promise provider is set up properly
FCPXML generation is successful (verified content)
All required pasteboard types are registered
Proper logging confirms data is being requested and provided
Current Pasteboard Types Offered:
com.apple.NSFilePromiseItemMetaData
com.apple.pasteboard.promised-file-name
com.apple.pasteboard.promised-suggested-file-name
com.apple.pasteboard.promised-file-content-type
Apple files promise pasteboard type
com.apple.pasteboard.NSFilePromiseID
com.apple.pasteboard.promised-file-url
com.apple.finalcutpro.xml.v1-10
com.apple.finalcutpro.xml.v1-9
com.apple.finalcutpro.xml
What additional requirements or considerations are needed to make FCPX accept the dragged FCPXML content? Are there specific requirements for workflow extensions regarding drag and drop operations with titles that aren't documented?
Any insights, especially from those who have implemented similar functionality in FCPX workflow extensions, would be greatly appreciated.
Technical Details:
macOS Version: 15.5 (24F74)
FCPX Version: 11.1.1
Extension built with SwiftUI and AppKit integration
Using NSFilePromiseProvider and NSPasteboardItemDataProvider
Full pasteboard type support for FCPXML versions