Web/API/HTMLCanvasElement/captureStream

The HTMLCanvasElement captureStream() method returns a MediaStream which includes a CanvasCaptureMediaStreamTrack containing a real-time video capture of the canvas's contents.

Syntax

MediaStream = canvas.captureStream(frameRate);

Parameters

frameRate Optional: A double-precision floating-point value that indicates the rate of capture of each frame. If not set, a new frame will be captured each time the canvas changes; if set to 0, frames will not be captured automatically; instead, they will only be captured when the returned track's requestFrame() method is called.

Return value

A reference to a MediaStream object, which has a single CanvasCaptureMediaStreamTrack in it.

Exceptions

NotSupportedError: The value of frameRate is negative.

Example

// Find the canvas element to capture
var canvasElt = document.querySelector('canvas');

// Get the stream
var stream = canvasElt.captureStream(25); // 25 FPS

// Do things to the stream
// E.g. Send it to another computer using an RTCPeerConnection
//      pc is an RTCPeerConnection created elsewhere
pc.addStream(stream);

Specifications

Specification	Status	Comment
Media Capture from DOM ElementsThe definition of 'HTMLCanvasElement.captureStream()' in that specification.	Working Draft	Initial definition

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
`captureStream` Experimental'	Chrome Full support 51	Edge Full support ≤79	Firefox Full support 43	IE No support No	Opera Full support 36	Safari Full support 11	WebView Android Full support 51	Chrome Android Full support 51	Firefox Android Full support 43	Opera Android Full support 36	Safari iOS Full support 11	Samsung Internet Android Full support 5.0

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.