xiangyu-sun / xsmetronome

Rewrite of Apple's Hello Metronome

XSMetronome

Simple demonstration of a metronome using AVAudioEngine and AVAudioPlayerNode to schedule buffers for timing accurate playback using scheduleBuffer:atTime:options:completionHandler:. The implementation also provides for a delegate object to call with the method (metronomeTicking:bar:beat:) which can be used for timing or to provide UI.

Main Files

Metronome.swift

• Source file for metronome implementation in all the targets.

TWGenerator.swift

• Generic TriangleWaveGenerator swift class used by all targets.

Version History

1.0 Initial release.

Requirements

Build

Xcode 8.2.1 or later, macOS 10.12, iOS 10.2, watchOS 3.1 SDKs

Runtime

macOS 10.9 or greater iOS 11.0 or greater watchOS 4 or greater

xsmetronome's Issues

Using an audio file for the sound

Thanks for making this! I'm interested in using an audio file for the click sound rather than a generated triangle wave, but it doesn't seem to work.

The change (also using only one sound rather than 2):

    let clickURL = Bundle.main.url(forResource: "metronome.click", withExtension: "wav")!
    let audioFile = try! AVAudioFile(forReading: clickURL)
    let audioFormat = audioFile.processingFormat
    let audioFrameCount = UInt32(audioFile.length)

    audioBuffer = AVAudioPCMBuffer(pcmFormat: audioFormat, frameCapacity: audioFrameCount)
    audioBuffer.frameLength = audioFrameCount
    try! audioFile.read(into: audioBuffer!)
    
    self.audioFormat = buffers[0]!.format
    self.bufferSampleRate = audioFormat.sampleRate
    
    initiazeDefaults()

    engine.attach(player)
    engine.connect(player, to:  engine.outputNode, fromBus: 0, toBus: 0, format: audioFormat)

This works perfectly at BPMs below 90 or so, but as the BPM increases the clicks get quieter and quieter until they disappear. Any thoughts on how to support audio files?

EDIT: Sound file works if it's 0.02 seconds in duration or less it seems.