ImageCapture.grabFrame()

The grabFrame() method of the ImageCapture interface takes a snapshot of the live video in a MediaStreamTrack and returns a Promise that resolves with a ImageBitmap containing the snapshot.

Syntax

const bitmapPromise = imageCapture.grabFrame()

Return value

A Promise that resolves to an ImageBitmap object.

Example

This example is extracted from this Simple Image Capture demo. It shows how to use the Promise returned by grabFrame() to copy the returned frame to a <canvas> element. For simplicy it does not show how to instantiate the ImageCapture object.

var grabFrameButton = document.querySelector('button#grabFrame');
var canvas = document.querySelector('canvas');

grabFrameButton.onclick = grabFrame;

function grabFrame() {
  imageCapture.grabFrame()
  .then(function(imageBitmap) {
    console.log('Grabbed frame:', imageBitmap);
    canvas.width = imageBitmap.width;
    canvas.height = imageBitmap.height;
    canvas.getContext('2d').drawImage(imageBitmap, 0, 0);
    canvas.classList.remove('hidden');
  })
  .catch(function(error) {
    console.log('grabFrame() error: ', error);
  });
}

Specifications

Specification Status Comment
MediaStream Image Capture
The definition of 'grabFrame()' in that specification.
Working Draft Initial definition.

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
grabFrame
Experimental
Chrome Full support 59Edge Full support ≤79Firefox ? IE ? Opera Full support 46Safari ? WebView Android Full support 59Chrome Android Full support 59Firefox Android ? Opera Android Full support 43Safari iOS ? Samsung Internet Android Full support 7.0

Legend

Full support
Full support
Compatibility unknown
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.