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'srequestFrame()
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 Elements The definition of 'HTMLCanvasElement.captureStream()' in that specification. |
Working Draft | Initial definition |
Browser compatibility
BCD tables only load in the browser
See also
HTMLMediaElement.captureStream()
, which allows capturing a stream from a media element.MediaStream
Media Capture and Streams API