Web/API/MediaStreamAudioDestinationNode/stream
The stream
property of the AudioContext
interface represents a MediaStream
containing a single audio MediaStreamTrack
with the same number of channels as the node itself.
You can use this property to get a stream out of the audio graph and feed it into another construct, such as a Media Recorder.
Syntax
var audioCtx = new AudioContext();
var destination = audioCtx.createMediaStreamDestination();
var myStream = destination.stream;
Value
A MediaStream
containing a single audio track. The audio track is a MediaStreamTrack
whose kind
is audio
.
Example
In the following simple example, we create a MediaStreamAudioDestinationNode
, an OscillatorNode
and a MediaRecorder
(the example will therefore only work in Firefox and Chrome at this time.) The MediaRecorder
is set up to record information from the MediaStreamDestinationNode
.
When the button is clicked, the oscillator starts, and the MediaRecorder
is started. When the button is stopped, the oscillator and MediaRecorder
both stop. Stopping the MediaRecorder
causes the dataavailable
event to fire, and the event data is pushed into the chunks
array. After that, the stop
event fires, a new blob
is made of type opus — which contains the data in the chunks
array, and a new window (tab) is then opened that points to a URL created from the blob.
From here, you can play and save the opus file.
<!DOCTYPE html>
<html>
<head>
<title>createMediaStreamDestination() demo</title>
</head>
<body>
<h1>createMediaStreamDestination() demo</h1>
<p>Encoding a pure sine wave to an Opus file </p>
<button>Make sine wave</button>
<audio controls></audio>
<script>
var b = document.querySelector("button");
var clicked = false;
var chunks = [];
var ac = new AudioContext();
var osc = ac.createOscillator();
var dest = ac.createMediaStreamDestination();
var mediaRecorder = new MediaRecorder(dest.stream);
osc.connect(dest);
b.addEventListener("click", function(e) {
if (!clicked) {
mediaRecorder.start();
osc.start(0);
e.target.innerHTML = "Stop recording";
clicked = true;
} else {
mediaRecorder.stop();
osc.stop(0);
e.target.disabled = true;
}
});
mediaRecorder.ondataavailable = function(evt) {
// push each chunk (blobs) in an array
chunks.push(evt.data);
};
mediaRecorder.onstop = function(evt) {
// Make blob out of our blobs, and open it.
var blob = new Blob(chunks, { 'type' : 'audio/ogg; codecs=opus' });
document.querySelector("audio").src = URL.createObjectURL(blob);
};
</script>
</body>
</html>
Note: You can [[../../../../../../../mdn.github.io/webaudio-examples/create-media-stream-destination/index|view this example live]], or study the source code, on Github.
Specifications
Specification | Status | Comment |
Web Audio APIThe definition of 'stream' in that specification. | Working Draft |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
stream
|
Chrome
Full support 14 |
Edge
Full support ≤18 |
Firefox
Full support 25 |
IE
No support No |
Opera
Full support 15 |
Safari
Full support 6 |
WebView Android
Full support Yes |
Chrome Android
Full support 18 |
Firefox Android
Full support 26 |
Opera Android
Full support 14 |
Safari iOS
Full support Yes |
Samsung Internet Android
Full support 1.0 |
Legend
- Full support
- Full support
- No support
- No support
See also
MediaStreamAudioDestinationNode.stream by Mozilla Contributors is licensed under CC-BY-SA 2.5.