AudioContext.createChannelSplitter

Syntax

var audioCtx = new AudioContext();
var splitter = audioCtx.createChannelSplitter(2);

Parameters

numberOfOutputs

The number of channels in the input audio stream that you want to output separately; the default is 6 if this parameter is not specified.

Returns

A ChannelSplitterNode.

Example

The following simple example shows how you could separate a stereo track (say, a piece of music), and process the left and right channel differently. To use them, you need to use the second and third parameters of the AudioNode.connect(AudioNode) method, which allow you to specify the index of the channel to connect from and the index of the channel to connect to.

var ac = new AudioContext();
ac.decodeAudioData(someStereoBuffer, function(data) {
 var source = ac.createBufferSource();
 source.buffer = data;
 var splitter = ac.createChannelSplitter(2);
 source.connect(splitter);
 var merger = ac.createChannelMerger(2);

 // Reduce the volume of the left channel only
 var gainNode = ac.createGain();
 gainNode.gain.value = 0.5;
 splitter.connect(gainNode, 0);

 // Connect the splitter back to the second input of the merger: we
 // effectively swap the channels, here, reversing the stereo image.
 gainNode.connect(merger, 0, 1);
 splitter.connect(merger, 1, 0);

 var dest = ac.createMediaStreamDestination();

 // Because we have used a ChannelMergerNode, we now have a stereo
 // MediaStream we can use to pipe the Web Audio graph to WebRTC,
 // MediaRecorder, etc.
 merger.connect(dest);
});

Specifications

Specification	Status	Comment
Web Audio API The definition of 'createChannelSplitter()' in that specification.	Working Draft

Browser compatibility

See also

• Using the Web Audio API