Short time Fourier transform


A streaming-ish short time Fourier transform.

var shortTimeFT = require("stft")
function onFreq(reim) {
  //Frequency stuff.  Process it here 
  istft(re, im)
function onTime(v) {
  //Got data, emit it here 
  console.log("out frame:", v)
var stft = shortTimeFT(1, 1024, onFreq)
var istft = shortTimeFT(-1, 1024, onTime)
//Feed stuff into signal 
stft(new Float32Array([1, 0, 0, 0, ... ])
npm install stft

Creates a function for processing a signal with a short time Fourier transform.

  • direction is a flag that determines whether the stft is forward or inverse

  • frame_size is the size of a frame for the stft

  • ondata is a callback that gets fired whenever data is ready to be processed

  • options is an optional object that takes the following parameters

    • options.hop_size the amount of samples between stft hops
    • options.window_func a windowing function, which takes a parameter from [0,1] and returns a weight

Returns A function that can be called with a frame (either real or complex) that adds a chunk of data to the stft queue

Short cut for require("stft")(1, frame_size, ondata, options)

Short cut for require("stft")(-1, frame_size, ondata, options)

(c) 2013 Mikola Lysenko. MIT License