Appending to AVAssetWriterInputPixelBufferAdaptor fails - swift

Question

I want to output a video file from the depth camera. Displaying the data works, but cannot append the pixelBuffer to the AVAssetWriterInputPixelBufferAdaptor. Unfortunately, there is no more info then a negative boolean.
In this function we setup the writer
func createWriter() {
do {
assetWriter = try AVAssetWriter(outputURL: movieURL() as URL, fileType: AVFileType.mov)
} catch let error as NSError {
print(error.localizedDescription)
return
}
let outputSettings = [
AVVideoCodecKey : AVVideoCodecType.h264,
AVVideoWidthKey : Int(currentVideoDimensions!.width),
AVVideoHeightKey : Int(currentVideoDimensions!.height)
] as [String : Any]
let assetWriterVideoInput = AVAssetWriterInput(mediaType: AVMediaType.video, outputSettings: outputSettings)
assetWriterVideoInput.transform = CGAffineTransform(rotationAngle: CGFloat(.pi / 2.0))
assetWriterVideoInput.expectsMediaDataInRealTime = true
let sourcePixelBufferAttributesDictionary = [
String(kCVPixelBufferPixelFormatTypeKey) : Int(kCVPixelFormatType_32BGRA),
String(kCVPixelBufferWidthKey) : Int(currentVideoDimensions!.width),
String(kCVPixelBufferHeightKey) : Int(currentVideoDimensions!.height),
String(kCVPixelFormatOpenGLESCompatibility) : kCFBooleanTrue!
] as [String : Any]
assetWriterPixelBufferInput = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: assetWriterVideoInput, sourcePixelBufferAttributes: sourcePixelBufferAttributesDictionary)
if assetWriter!.canAdd(assetWriterVideoInput) {
assetWriter!.add(assetWriterVideoInput)
} else {
print("no way\(assetWriterVideoInput)")
}
}
which is used later to append the pixelbuffers after a frame is recorded
public func captureOutput(_ captureOutput: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection) {
autoreleasepool {
connection.videoOrientation = AVCaptureVideoOrientation.landscapeLeft;
let pixelBuffer : CVPixelBuffer? = CMSampleBufferGetImageBuffer(sampleBuffer)
let cameraImage = CIImage(cvPixelBuffer: pixelBuffer!)
let previewImage: CIImage
previewImage = depthMap ?? cameraImage
let displayImage = UIImage(ciImage: previewImage)
let formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer)!
self.currentVideoDimensions = CMVideoFormatDescriptionGetDimensions(formatDescription)
self.currentSampleTime = CMSampleBufferGetOutputPresentationTimeStamp(sampleBuffer)
if self.isWriting {
if self.assetWriterPixelBufferInput?.assetWriterInput.isReadyForMoreMediaData == true {let success = self.assetWriterPixelBufferInput?.append(pixelBuffer!, withPresentationTime: self.currentSampleTime!)
if success == false {
print("Pixel Buffer failed")
}
}
}
DispatchQueue.main.async { [weak self] in
self?.imageView.image = displayImage
}
}
}
We checked Image and Buffer sizes and they were the same, appending still doesn't work and there is no proper error message.