Can not read audio from file.

[ailias]

When I specify the url variable to Config object, it will call OutputSignalTracker.start（）function, but it can not enter this function and exit the program: audioEngine.outputNode.installTap(onBus: bus, bufferSize: bufferSize, format: nil) { (buffer: AVAudioPCMBuffer!, time: AVAudioTime!) in DispatchQueue.main.async { self.delegate?.signalTracker(self, didReceiveBuffer: buffer, atTime: time) }}

[kocharyanvahe]

Also, I have the same problem.

[hepiyellow]

Yeah, Can you give an example of how to analyze an audio file and get the Pitch array or something? And, how would I know the timing info (offset in milliseconds) of each Pitch sample?

[jhristov]

What I found is a couple of issues in OutputSignalTracker which prevent the pitch output. First, installTap() has no effect on audioEngine - one has to substitute with audioPlayer. Second, the delegate in the closure was always nil so self.delegate?.signalTracker() was never called. Here is my replacement code which should give you an idea how to get some readings. It goes in the start() method of OutputSignalTracker. One must import Pitchy too.

      let factory = EstimationFactory()
      let estimator = factory.create(.yin) // Choose pitch method here!
      let queue = DispatchQueue(label: "BeethovenQueue", attributes: [])

      self.audioPlayer.installTap(onBus: 0, bufferSize: self.bufferSize, format: nil) { (buffer, time) in

          queue.async { [weak self] in
            guard let `self` = self else { return }

            do {
              let transformedBuffer = try estimator.transformer.transform(buffer: buffer)
              let frequency = try estimator.estimateFrequency(
                sampleRate: Float(time.sampleRate),
                buffer: transformedBuffer)
              let pitch = try Pitch(frequency: Double(frequency))
            print(time,pitch)

              DispatchQueue.main.async { [weak self] in
                guard let `self` = self else { return }
                //self.delegate?.pitchEngine(self, didReceivePitch: pitch)
              }
            } catch {
              DispatchQueue.main.async { [weak self] in
                guard let `self` = self else { return }
                //self.delegate?.pitchEngine(self, didReceiveError: error)
              }
            }
        }

    }

One would then start the tracking with:

        let config = Config(
          bufferSize: 4096,
          estimationStrategy: .yin, // has no effect, has to be set in the estimator, see above
          audioUrl: Bundle.main.url(forResource: "sound_file", withExtension: "wav")!
        )

        let pitchEngine = PitchEngine(config: config)
        pitchEngine.start()

[mannyvw]

@jhristov perfect. Yep i replaced the following line in OutputSignalTracker::start

audioEngine.outputNode.installTap(onBus: bus, bufferSize: bufferSize, format: nil)

With

audioPlayer.installTap(onBus: bus, bufferSize: bufferSize, format: nil)

and everything else works. Good work