Stereophonic

audio sample player library (written in go)

What it does

It plays audio samples and let's you tweak them in realtime (reverse, loop, filter, adsr envelopes, etc).

Prerequisites

installation of portaudio & libsndfile is required prior to usage of this library

Usage

Check out _examples/ but the gist is:

Create an engine (then tweak/start it)

	engine, err := stereophonic.New()
	if err != nil {
		log.Fatal(err)
	}
	defer engine.Close()
	
	// engine configuration goes here (before start)
	// one may want to change the output device, sample rate, etc
	
	// start engine
	if err := engine.Start(); err != nil {
		log.Fatal(err)
	}

Load some audio samples (into engine slot indices)

	// the slot where the sample is loaded into the engine
	slot := 1
	if err := engine.Load(slot, sampleDirectory+"808kick.wav"); err != nil {
		log.Fatal(err)
	}

Prepare events (of either limited or unlimited duration)

	// this specifies how long to wait before playback starts
	// once the event is actually passed to Play()
	delayInSeconds := 0.0
	// duration is always specified in seconds
	// duration <= 0 will incite an unlimited duration event which must be released
	unlimitedDuration := 0.0
	event, err := engine.Prepare(slot, delayInSeconds, unlimitedDuration)
	if err != nil {
		log.Fatal(err)
	}
	// reverse playback
	event.SetReverse(true)
	// trigger (to update current playback position relative to direction)
	event.Trigger()
	// low pass filter is default
	// cutoff ranges from 0 to 1 * the nyquist frequency (dependent on sample rate)
	event.SetFilterCutoff(0.1)
	// set a note / pitch value (an octave up)
	event.SetNote(12)

Play events (releasing the unlimited duration events as necessary)

	engine.Play(event)
	time.Sleep(3 * time.Second)
	event.Release()