audio-analyser

Audio analyser stream. Provides API of the AnalyserNode for audio-streams. In all respects can be used in the same way.

Usage

var Analyser = require('audio-analyser');
var Generator = require('audio-generator');


var analyser = new Analyser({
	// Magnitude diapasone, in dB
	minDecibels: -100,
	maxDecibels: -30,

	// Number of time samples to transform to frequency
	fftSize: 1024,

	// Number of frequencies, twice less than fftSize
	frequencyBinCount: 1024/2,

	// Smoothing, or the priority of the old data over the new data
	smoothingTimeConstant: 0.2,

	// Number of channel to analyse
	channel: 0,

	// Size of time data to buffer
	bufferSize: 44100,

	// Windowing function for fft, https://github.com/scijs/window-functions
	applyWindow: function (sampleNumber, totalSamples) {
	}

	//...pcm-stream params, if required
});


//AnalyserNode methods

// Copies the current frequency data into a Float32Array array passed into it.
analyser.getFloatFrequencyData(arr);

// Copies the current frequency data into a Uint8Array passed into it.
analyser.getByteFrequencyData(arr);

// Copies the current waveform, or time-domain data into a Float32Array array passed into it.
analyser.getFloatTimeDomainData(arr);

// Copies the current waveform, or time-domain data into a Uint8Array passed into it.
analyser.getByteTimeDomainData(arr);


//Shortcut methods

//return array with frequency data in decibels of size <= fftSize
analyser.getFrequencyData(size);

//return array with time data of size <= self.bufferSize (way more than fftSize)
analyser.getTimeData(size);


//Can be used both as a sink or pass-through
Generator().pipe(analyser);

Related

audio-render — render audio streams.
audio-spectrum — render audio spectrum.
audio-spectrogram — render audio spectrogram.
audio-waveform — render audio waveform.
audio-stat — render any kind of audio info: waveform, spectrogram etc.
pcm-util — utils for work with pcm-streams.
ndarray-fft — implementation of fft for ndarrays.