The MediaStreamTrackAudioSourceNode
interface is a type of AudioNode
which represents a source of audio data taken from a specific MediaStreamTrack
obtained through the WebRTC or Media Capture and Streams APIs. The audio itself might be input from a microphone or other audio sampling device, or might be received through a RTCPeerConnection
, among other posible options.
A MediaStreamTrackAudioSourceNode
has no inputs and exactly one output, and is created using the AudioContext.createMediaStreamTrackSource()
method. This interface is similar to MediaStreamAudioSourceNode
, except it lets you specifically state the track to use, rather than assuming the first audio track on a stream.
Number of inputs | 0 |
---|---|
Number of outputs | 1 |
Channel count | defined by the first audio MediaStreamTrack passed to the AudioContext.createMediaStreamTrackSource() method that created it. |
Constructor
new MediaStreamTrackAudioSourceNode()
- Creates a new
MediaStreamTrackAudioSourceNode
object instance with the specified options.
Properties
The MediaStreamTrackAudioSourceNode
interface has no properties of its own; however, it inherits the properties of its parent, AudioNode
.
Methods
Inherits methods from its parent, AudioNode
.
Example
In this example, we grab a media (audio + video) stream from navigator.getUserMedia
, feed the media into a <video>
element to play then mute the audio, but then also feed the audio into a MediaStreamAudioSourceNode
. Next, we feed this source audio into a low pass BiquadFilterNode
(which effectively serves as a bass booster), then a AudioDestinationNode
.
The range slider below the <video>
element controls the amount of gain given to the lowpass filter — increase the value of the slider to make the audio sound more bass heavy!
Note: You can see this example running live, or view the source.
var pre = document.querySelector('pre'); var video = document.querySelector('video'); var myScript = document.querySelector('script'); var range = document.querySelector('input'); // getUserMedia block - grab stream // put it into a MediaStreamAudioSourceNode // also output the visuals into a video element if (navigator.mediaDevices) { console.log('getUserMedia supported.'); navigator.mediaDevices.getUserMedia ({audio: true, video: true}) .then(function(stream) { video.srcObject = stream; video.onloadedmetadata = function(e) { video.play(); video.muted = true; }; // Create a MediaStreamAudioSourceNode // Feed the HTMLMediaElement into it var audioCtx = new AudioContext(); var source = audioCtx.createMediaStreamSource(stream); // Create a biquadfilter var biquadFilter = audioCtx.createBiquadFilter(); biquadFilter.type = "lowshelf"; biquadFilter.frequency.value = 1000; biquadFilter.gain.value = range.value; // 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(biquadFilter); biquadFilter.connect(audioCtx.destination); // Get new mouse pointer coordinates when mouse is moved // then set new gain value range.oninput = function() { biquadFilter.gain.value = range.value; } }) .catch(function(err) { console.log('The following gUM error occured: ' + err); }); } else { console.log('getUserMedia not supported on your browser!'); } // dump script to pre element pre.innerHTML = myScript.innerHTML;
Note: As a consequence of calling createMediaStreamSource()
, audio playback from the media stream will be re-routed into the processing graph of the AudioContext
. So playing/pausing the stream can still be done through the media element API and the player controls.
Specification
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'MediaStreamTrackAudioSourceNode' in that specification. |
Working Draft |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
MediaStreamTrackAudioSourceNode | Chrome No support No | Edge No support No | Firefox Full support 68 | IE No support No | Opera No support No | Safari No support No | WebView Android No support No | Chrome Android No support No | Firefox Android Full support 68 | Opera Android No support No | Safari iOS No support No | Samsung Internet Android No support No |
MediaStreamTrackAudioSourceNode() constructor | Chrome No support No | Edge No support No | Firefox
Full support
68
| IE No support No | Opera No support No | Safari No support No | WebView Android No support No | Chrome Android No support No | Firefox Android
Full support
68
| Opera Android No support No | Safari iOS No support No | Samsung Internet Android No support No |
mediaStreamTrack | Chrome No support No | Edge No support No | Firefox Full support 68 | IE No support No | Opera No support No | Safari No support No | WebView Android No support No | Chrome Android No support No | Firefox Android Full support 68 | Opera Android No support No | Safari iOS No support No | Samsung Internet Android No support No |
Legend
- Full support
- Full support
- No support
- No support
- See implementation notes.
- See implementation notes.