The getFloatTimeDomainData()
method of the AnalyserNode
Interface copies the current waveform, or time-domain, data into a Float32Array
array passed into it.
AnalyserNode.getFloatTimeDomainData()
Syntax
getFloatTimeDomainData(array)
Parameters
-
array
-
The
Float32Array
that the time domain data will be copied to. If the array has fewer elements than theAnalyserNode.fftSize
, excess elements are dropped. If it has more elements than needed, excess elements are ignored.
Return value
None.
Examples
The following example shows basic usage of an AudioContext
to create an AnalyserNode
, then requestAnimationFrame
and <canvas>
to collect time domain data repeatedly and draw an "oscilloscope style" output of the current audio input. For more complete applied examples/information, check out our Voice-change-O-matic-float-data demo (see the source code too).
var audioCtx = new (window.AudioContext || window.webkitAudioContext)(); var analyser = audioCtx.createAnalyser(); ... analyser.fftSize = 1024; var bufferLength = analyser.fftSize; console.log(bufferLength); var dataArray = new Float32Array(bufferLength); canvasCtx.clearRect(0, 0, WIDTH, HEIGHT); function draw() { drawVisual = requestAnimationFrame(draw); analyser.getFloatTimeDomainData(dataArray); canvasCtx.fillStyle = 'rgb(200, 200, 200)'; canvasCtx.fillRect(0, 0, WIDTH, HEIGHT); canvasCtx.lineWidth = 2; canvasCtx.strokeStyle = 'rgb(0, 0, 0)'; canvasCtx.beginPath(); var sliceWidth = WIDTH * 1.0 / bufferLength; var x = 0; for(var i = 0; i < bufferLength; i++) { var v = dataArray[i] * 200.0; var y = HEIGHT/2 + v; if(i === 0) { canvasCtx.moveTo(x, y); } else { canvasCtx.lineTo(x, y); } x += sliceWidth; } canvasCtx.lineTo(canvas.width, canvas.height/2); canvasCtx.stroke(); }; draw();
Specifications
Specification |
---|
Web Audio API # dom-analysernode-getfloattimedomaindata |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
getFloatTimeDomainData |
35
|
12
|
30
|
No
|
22
|
14.1
|
37
|
35
|
30
|
22
|
14.5
|
3.0
|
See also
© 2005–2021 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode/getFloatTimeDomainData