SIGABRT, брошенный на CIImage только иногда

Question

У меня проблема в том, что иногда (1 из 250) videoImage выдает ошибку SIGABRT, возникающую из libc++abi.dylib: Pure virtual function called!

Я не совсем уверен, почему любой из них происходит. Я не испытал достаточно SIGABRT (кроме ошибок раскадровки), чтобы точно знать, как отлаживать.

private var videoImage: CIImage?
private var videoPixelBuffer: CVPixelBuffer?

    func dataOutputSynchronizer(_ synchronizer: AVCaptureDataOutputSynchronizer, didOutput synchronizedDataCollection: AVCaptureSynchronizedDataCollection) {

//        print(self.videoDevice.activeVideoMinFrameDuration, self.videoDevice.activeVideoMaxFrameDuration)
        guard let syncedVideoData = synchronizedDataCollection.synchronizedData(for: self.videoDataOutput) as? AVCaptureSynchronizedSampleBufferData else { return }
        guard !syncedVideoData.sampleBufferWasDropped else {
            print(syncedVideoData.droppedReason.rawValue)
            return
        }
        let videoSampleBuffer = syncedVideoData.sampleBuffer

        let syncedDepthData = synchronizedDataCollection.synchronizedData(for: self.depthDataOutput) as? AVCaptureSynchronizedDepthData
        var depthData = syncedDepthData?.depthData
        if let syncedDepthData = syncedDepthData, syncedDepthData.depthDataWasDropped {
            print("dropped depth:\(syncedDepthData)")
            depthData = nil
        }

        let syncedMetaData = synchronizedDataCollection.synchronizedData(for: self.metadataOutput) as? AVCaptureSynchronizedMetadataObjectData
        var face: AVMetadataObject? = nil
        if let firstFace = syncedMetaData?.metadataObjects.first {
            face = self.videoDataOutput.transformedMetadataObject(for: firstFace, connection: self.videoConnection)
        }
        guard let imagePixelBuffer = CMSampleBufferGetImageBuffer(videoSampleBuffer) else { fatalError() }
        guard let depthMap = depthData?.depthDataMap else { return }

        CVPixelBufferLockBaseAddress(imagePixelBuffer,
                                     CVPixelBufferLockFlags.readOnly)

        self.videoPixelBuffer = displayEqualizedPixelBuffer(pixelBuffer: imagePixelBuffer)

        CVPixelBufferUnlockBaseAddress(imagePixelBuffer,
                                       CVPixelBufferLockFlags.readOnly)
    }

    func displayEqualizedPixelBuffer(pixelBuffer: CVPixelBuffer, scaleToBuffer: CVPixelBuffer? = nil) -> CVPixelBuffer? {

        let scaleWidth:Int = scaleToBuffer != nil ? CVPixelBufferGetWidth(scaleToBuffer!) : CVPixelBufferGetWidth(pixelBuffer)
        let scaleHeight:Int = scaleToBuffer != nil ? CVPixelBufferGetHeight(scaleToBuffer!) : CVPixelBufferGetHeight(pixelBuffer)

        let flags = CVPixelBufferLockFlags(rawValue: 0)
        guard kCVReturnSuccess == CVPixelBufferLockBaseAddress(pixelBuffer, flags) else {
            return nil
        }

        defer { CVPixelBufferUnlockBaseAddress(pixelBuffer, flags) }

        guard let srcData = CVPixelBufferGetBaseAddress(pixelBuffer) else {
            print("Error: could not get pixel buffer base address")
            return nil
        }

        let srcBytesPerRow = CVPixelBufferGetBytesPerRow(pixelBuffer)
        var srcBuffer = vImage_Buffer(data: srcData,
                                      height: vImagePixelCount(CVPixelBufferGetHeight(pixelBuffer)),
                                      width: vImagePixelCount(CVPixelBufferGetWidth(pixelBuffer)),
                                      rowBytes: srcBytesPerRow)

        let destBytesPerRow = scaleWidth*4
        guard let destData = malloc(scaleHeight*destBytesPerRow) else {
            print("Error: out of memory")
            return nil
        }

        var destBuffer = vImage_Buffer(data: destData,
                                       height: vImagePixelCount(scaleHeight),
                                       width: vImagePixelCount(scaleWidth),
                                       rowBytes: destBytesPerRow)

        let error = vImageScale_ARGB8888(&srcBuffer, &destBuffer, nil, vImage_Flags(kvImageLeaveAlphaUnchanged))
        if error != kvImageNoError {
            print("Error:", error)
            free(destData)
            return nil
        }

        let releaseCallback: CVPixelBufferReleaseBytesCallback = { _, ptr in
            if let ptr = ptr {
                free(UnsafeMutableRawPointer(mutating: ptr))
            }
        }

        let pixelFormat = CVPixelBufferGetPixelFormatType(pixelBuffer)
        var dstPixelBuffer: CVPixelBuffer?
        let status = CVPixelBufferCreateWithBytes(nil, scaleWidth, scaleHeight,
                                                  pixelFormat, destData,
                                                  destBytesPerRow, releaseCallback,
                                                  nil, nil, &dstPixelBuffer)
        if status != kCVReturnSuccess {
            print("Error: could not create new pixel buffer")
            free(destData)
            return nil
        }
        return dstPixelBuffer
    }

videoImage = CIImage(cvPixelBuffer: videoPixelBuffer)

print(videoImage)

Это обратный след:

 thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
    frame #0: 0x00000001953b6efc libsystem_kernel.dylib`__pthread_kill + 8
    frame #1: 0x00000001952d68b8 libsystem_pthread.dylib`pthread_kill + 228
    frame #2: 0x0000000195266a74 libsystem_c.dylib`abort + 104
    frame #3: 0x000000019537e3c8 libc++abi.dylib`abort_message + 132
    frame #4: 0x000000019538c740 libc++abi.dylib`__cxa_pure_virtual + 24
    frame #5: 0x0000000196e95fe0 CoreImage`-[CIImage extent] + 32
    frame #6: 0x0000000196e961c4 CoreImage`-[CIImage description] + 44
    frame #7: 0x00000001cb06439c libswiftFoundation.dylib`merged protocol witness for Swift.CustomStringConvertible.description.getter : Swift.String in conformance __C.NSObject : Swift.CustomStringConvertible in Foundation + 24
    frame #8: 0x00000001a2eb6ee0 libswiftCore.dylib`function signature specialization <Arg[1] = Exploded, Arg[2] = Exploded> of generic specialization <Swift._Stdout> of Swift._print<A where A: Swift.TextOutputStream>(_: Swift.Array<Any>, separator: Swift.String, terminator: Swift.String, to: inout A) -> () + 1172
    frame #9: 0x00000001a2d81c6c libswiftCore.dylib`Swift.print(_: Any..., separator: Swift.String, terminator: Swift.String) -> () + 32
  * frame #10: 0x00000001037ca360 DepthCamera`specialized RealtimeDepthMaskViewController.draw(self=0x000000011d805c00) at RealTimeDepthViewController.swift:524:13 [opt]
    frame #11: 0x00000001037c5000 DepthCamera`@objc RealtimeDepthMaskViewController.draw(in:) [inlined] DepthCamera.RealtimeDepthMaskViewController.draw(in: __C.MTKView) -> () at <compiler-generated>:0 [opt]
    frame #12: 0x00000001037c4ffc DepthCamera`@objc RealtimeDepthMaskViewController.draw(in:) at <compiler-generated>:499 [opt]