Web/API/AudioBufferSourceNode/loopEnd

From Get docs

The loopEnd property of the AudioBufferSourceNode interface specifies is a floating point number specifying, in seconds, at what offset into playing the AudioBuffer playback should loop back to the time indicated by the loopStart property. This is only used if the loop property is true.


Syntax

AudioBufferSourceNode.loopEnd = endOffsetInSeconds;

var endOffsetInSeconds = AudioBufferSourceNode.loopEnd;

Value

A floating-point number indicating the offset, in seconds, into the audio buffer at which each loop will loop return to the beginning of the loop (that is, the current play time gets reset to AudioBufferSourceNode.loopStart). This property is only used if the loop property is true.

The default value is 0.

Example

In this example, the AudioContext.decodeAudioData() function is used to decode an audio track and put it into an AudioBufferSourceNode. Buttons are provided to play and stop the audio playback, and slider controls are used to change the playbackRate, loopStart and loopEnd properties on the fly.

When the audio is played to the end, it loops, but you can control how long the loops last by altering loopStart and loopEnd. For example, if you set their values to 20 and 25, respectively, then begin playback, the sound will play normally until it reaches the 25 second mark. Then the current play position will loop back to the 20 second mark and continue playing until the 25 second mark, ad infinitum (or at least until stop() is called).

For a full working example, see [[../../../../../../../mdn.github.io/webaudio-examples/decode-audio-data/index|this code running live]], or view the source.


function getData() {
  source = audioCtx.createBufferSource();
  request = new XMLHttpRequest();

  request.open('GET', 'viper.ogg', true);

  request.responseType = 'arraybuffer';


  request.onload = function() {
    var audioData = request.response;

    audioCtx.decodeAudioData(audioData, function(buffer) {
        myBuffer = buffer;
        songLength = buffer.duration;
        source.buffer = myBuffer;
        source.playbackRate.value = playbackControl.value;
        source.connect(audioCtx.destination);
        source.loop = true;

        loopstartControl.setAttribute('max', Math.floor(songLength));
        loopendControl.setAttribute('max', Math.floor(songLength));
      },

      function(e){"Error with decoding audio data" + e.err});

  }

  request.send();
}

  ...

loopstartControl.oninput = function() {
  source.loopStart = loopstartControl.value;
  loopstartValue.innerHTML = loopstartControl.value;
}

loopendControl.oninput = function() {
  source.loopEnd = loopendControl.value;
  loopendValue.innerHTML = loopendControl.value;
}

Specifications

Specification Status Comment
Web Audio APIThe definition of 'loopEnd' in that specification. Working Draft  

Browser compatibility

Update compatibility data on GitHub

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
loopEnd Chrome

Full support 24

Edge

Full support 12

Firefox

Full support 25

IE

No support No

Opera

Full support 15

Safari

Full support 6

WebView Android

Full support ≤37

Chrome Android

Full support 25

Firefox Android

Full support 26

Opera Android

Full support 14

Safari iOS

Full support 6

Samsung Internet Android

Full support 1.5

Legend

Full support  
Full support
No support  
No support


See also