wav-spectrogram

A Node.js library for loading WAV files and drawing a spectrogram to a canvas.

$3

Load WAV file using a input object, read contents as an array buffer and pass to function with a canvas of the desired dimensions:
``



var wavSpectro = require('wav-spectrogram');



var fileInput = document.getElementById('file-input');

var canvasElem = document.getElementById('spectrogram-canvas');



var reader = new FileReader();



reader.onload = function() {



    var arrayBuffer = reader.result;



    wavSpectro.drawSpectrogram({arrayBuffer: arrayBuffer, canvasElem: canvasElem, cmap: 'jet'}, function () {

    

        console.log("Done.");

    

    });



};



reader.readAsArrayBuffer(fileInput.files[0]);





$3



The draw function must be handed parameters in an object, named as such. Parameters with default values can be left out.



Option         | Default     | Description

---------------|-------------|------------

arrayBuffer

  | -           | Array buffer read from WAV file

canvasElem

   | -           | Canvas element to draw to (spectrogram will fill dimensions)

cmap

         | -           | Colour map to draw using colormap module

nfft

         | 512         | Buffer size of Fast Fourier Transform

frameLengthMs

| 0.1         | Length of frames signal is divided into before FFT is applied (given in milliseconds)

frameStepMs | 0.005 | Size of steps forward each frame takes (if less than frameLengthMs

 then frames overlap)

errorHandler` | - | An error handling function which will be called if loading the wav file fails

As well as the params object, the draw function accepts a callback function.