electron/docs/api/desktop-capturer.md

desktopCapturer

Access information about media sources that can be used to capture audio and video from the desktop using the navigator.mediaDevices.getUserMedia API.

Process: Renderer

The following example shows how to capture video from a desktop window whose title is Electron:

// In the renderer process.
const {desktopCapturer} = require('electron')

desktopCapturer.getSources({types: ['window', 'screen']}, (error, sources) => {
  if (error) throw error
  for (let i = 0; i < sources.length; ++i) {
    if (sources[i].name === 'Electron') {
      navigator.mediaDevices.getUserMedia({
        audio: false,
        video: {
          mandatory: {
            chromeMediaSource: 'desktop',
            chromeMediaSourceId: sources[i].id,
            minWidth: 1280,
            maxWidth: 1280,
            minHeight: 720,
            maxHeight: 720
          }
        }
      })
      .then((stream) => handleStream(stream))
      .catch((e) => handleError(e))
      return
    }
  }
})

function handleStream (stream) {
  const video = document.querySelector('video')
  video.srcObject = stream
  video.onloadedmetadata = (e) => video.play()
}

function handleError (e) {
  console.log(e)
}

To capture video from a source provided by desktopCapturer the constraints passed to navigator.mediaDevices.getUserMedia must include chromeMediaSource: 'desktop', and audio: false.

To capture both audio and video from the entire desktop the constraints passed to navigator.mediaDevices.getUserMedia must include chromeMediaSource: 'desktop', for both audio and video, but should not include a chromeMediaSourceId constraint.

const constraints = {
  audio: {
    mandatory: {
      chromeMediaSource: 'desktop'
    }
  },
  video: {
    mandatory: {
      chromeMediaSource: 'desktop'
    }
  }
}

Methods

The desktopCapturer module has the following methods:

desktopCapturer.getSources(options, callback)

• options Object
  • types String[] - An array of Strings that lists the types of desktop sources to be captured, available types are screen and window.
  • thumbnailSize Size (optional) - The size that the media source thumbnail should be scaled to. Default is 150 x 150.
• callback Function
  • error Error
  • sources DesktopCapturerSource[]

Starts gathering information about all available desktop media sources, and calls callback(error, sources) when finished.

sources is an array of DesktopCapturerSource objects, each DesktopCapturerSource represents a screen or an individual window that can be captured.