avfoundation

I'm trying to capture frames from camera and associated motion data. For synchronization I'm using timestamps. Video and motion is written to a file and then processed. In that process I can calculate motion-frames offset for every video. Turns out motion data and video data for same timestamp is offset from each other by different time from 0.2 sec up to 0.3 sec. This offset is constant for one video but varies from video to video. If it was same offset every time I would be able to subtract some calibrated value but it's not. Is there a good way to synchronize timestamps? Maybe I'm not

I am using UIViewControllerTransitioningDelegate to build custom transitions between two view controllers (from a MKMapView ) to a custom Camera built on ( AVFoundation ). Everything goes well until I call the presentViewController and the phone seems to hang for about 1 second (when I log everything out). This even seems to happen when I am transitioning to a much simpler view (I have a view controller that only displays a UITextview and even with that there appears to be about a .4 - .5 second delay before the transition is actually called). This is currently how I am calling the transition

AVAudioConverter seems broken in iOS 10. The code was working in iOS 9 and now Error Domain=NSOSStatusErrorDomain Code=-50 "(null)" is returned no matter what audio format is used. It suprises me every year, that basic library functionality stops working. func audioConverterFailureIOS10() { // Describe the audio format let inFormat = AVAudioFormat(standardFormatWithSampleRate: 44100, channels: 2) let outFormat = AVAudioFormat(standardFormatWithSampleRate: 22050, channels: 2) // Allocate buffers let outBuffer = AVAudioPCMBuffer(pcmFormat: outFormat, frameCapacity: 1024) // Create an input block

This has been asked before, but something must have changed in Swift since it was asked. I am trying to store CMSampleBuffer objects returned from an AVCaptureSession to be processed later. After some experimentation I discovered that AVCaptureSession must be reusing its CMSampleBuffer references. When I try to keep more than 15 the session hangs. So I thought I would make copies of the sample buffers. But I can't seem to get it to work. Here is what I have written: var allocator: Unmanaged<CFAllocator>! = CFAllocatorGetDefault() var bufferCopy: UnsafeMutablePointer<CMSampleBuffer?> let err =

I have an issue with the delegate method didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection of AVCaptureOutput . It stops getting called within a second or two when I'm adding the sampleBuffer to a CFArray . If I remove the CFArray code, the delegate method continues to get called so I have no idea why the CFArray code is causing it to stop. I'd appreciate any help. @property CFMutableArrayRef sampleBufferArray; - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:

I'm converting an mp3 to m4a in Swift with code based on this . It works when I generate a PCM file. When I change the export format to m4a it generates a file but it won't play. Why is it corrupt? Here is the code so far: import AVFoundation import UIKit class ViewController: UIViewController { var rwAudioSerializationQueue:dispatch_queue_t! var asset:AVAsset! var assetReader:AVAssetReader! var assetReaderAudioOutput:AVAssetReaderTrackOutput! var assetWriter:AVAssetWriter! var assetWriterAudioInput:AVAssetWriterInput! var outputURL:NSURL! override func viewDidLoad() { super.viewDidLoad() let