The createMediaElementSource()
method of the AudioContext
Interface is used to create a new MediaElementAudioSourceNode
object, given an existing HTML <audio>
or <video>
element, the audio from which can then be played and manipulated.
For more details about media element audio source nodes, check out the MediaElementAudioSourceNode
reference page.
Syntax
var audioCtx = new AudioContext(); var source = audioCtx.createMediaElementSource(myMediaElement);
Parameters
myMediaElement
- An
HTMLMediaElement
object that you want to feed into an audio processing graph to manipulate.
Returns
A MediaElementAudioSourceNode
.
Example
This simple example creates a source from an <audio>
element using createMediaElementSource()
, then passes the audio through a GainNode
before feeding it into the AudioDestinationNode
for playback. When the mouse pointer is moved, the updatePage()
function is invoked, which calculates the current gain as a ratio of mouse Y position divided by overall window height. You can therefore increase and decrease the volume of the playing music by moving the mouse pointer up and down.
Note: You can also view this example running live, or view the source.
var audioCtx = new (window.AudioContext || window.webkitAudioContext)(); var myAudio = document.querySelector('audio'); var pre = document.querySelector('pre'); var myScript = document.querySelector('script'); pre.innerHTML = myScript.innerHTML; // Create a MediaElementAudioSourceNode // Feed the HTMLMediaElement into it var source = audioCtx.createMediaElementSource(myAudio); // Create a gain node var gainNode = audioCtx.createGain(); // Create variables to store mouse pointer Y coordinate // and HEIGHT of screen var CurY; var HEIGHT = window.innerHeight; // Get new mouse pointer coordinates when mouse is moved // then set new gain value document.onmousemove = updatePage; function updatePage(e) { CurY = (window.Event) ? e.pageY : event.clientY + (document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop); gainNode.gain.value = CurY/HEIGHT; } // connect the AudioBufferSourceNode to the gainNode // and the gainNode to the destination, so we can play the // music and adjust the volume using the mouse cursor source.connect(gainNode); gainNode.connect(audioCtx.destination);
Note: As a consequence of calling createMediaElementSource()
, audio playback from the HTMLMediaElement
will be re-routed into the processing graph of the AudioContext. So playing/pausing the media can still be done through the media element API and the player controls.
Specifications
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'createMediaElementSource()' in that specification. |
Working Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 10.0webkit | 25.0 (25.0) | Not supported | 15.0webkit 22 |
6.0webkit |
Feature | Android | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | ? | 26.0 | 1.2 | ? | ? | ? | 33.0 |