# 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: [Main](../glossary.md#main-process) The following example shows how to capture video from a desktop window whose title is `Electron`: ```js // main.js const { app, BrowserWindow, desktopCapturer, session } = require('electron') app.whenReady().then(() => { const mainWindow = new BrowserWindow() session.defaultSession.setDisplayMediaRequestHandler((request, callback) => { desktopCapturer.getSources({ types: ['screen'] }).then((sources) => { // Grant access to the first screen found. callback({ video: sources[0], audio: 'loopback' }) }) // If true, use the system picker if available. // Note: this is currently experimental. If the system picker // is available, it will be used and the media request handler // will not be invoked. }, { useSystemPicker: true }) mainWindow.loadFile('index.html') }) ``` ```js // renderer.js const startButton = document.getElementById('startButton') const stopButton = document.getElementById('stopButton') const video = document.querySelector('video') startButton.addEventListener('click', () => { navigator.mediaDevices.getDisplayMedia({ audio: true, video: { width: 320, height: 240, frameRate: 30 } }).then(stream => { video.srcObject = stream video.onloadedmetadata = (e) => video.play() }).catch(e => console.log(e)) }) stopButton.addEventListener('click', () => { video.pause() }) ``` ```html

``` See [`navigator.mediaDevices.getDisplayMedia`](https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/getDisplayMedia) for more information. > [!NOTE] > `navigator.mediaDevices.getDisplayMedia` does not permit the use of `deviceId` for > selection of a source - see [specification](https://w3c.github.io/mediacapture-screen-share/#constraints). ## Methods The `desktopCapturer` module has the following methods: ### `desktopCapturer.getSources(options)` * `options` Object * `types` string[] - An array of strings that lists the types of desktop sources to be captured, available types can be `screen` and `window`. * `thumbnailSize` [Size](structures/size.md) (optional) - The size that the media source thumbnail should be scaled to. Default is `150` x `150`. Set width or height to 0 when you do not need the thumbnails. This will save the processing time required for capturing the content of each window and screen. * `fetchWindowIcons` boolean (optional) - Set to true to enable fetching window icons. The default value is false. When false the appIcon property of the sources return null. Same if a source has the type screen. Returns `Promise` - Resolves with an array of [`DesktopCapturerSource`](structures/desktop-capturer-source.md) objects, each `DesktopCapturerSource` represents a screen or an individual window that can be captured. > [!NOTE] > * Capturing audio requires `NSAudioCaptureUsageDescription` Info.plist key on macOS 14.2 Sonoma and higher - [read more](#macos-versions-142-or-higher). > * Capturing the screen contents requires user consent on macOS 10.15 Catalina or higher, which can detected by [`systemPreferences.getMediaAccessStatus`][]. [`navigator.mediaDevices.getUserMedia`]: https://developer.mozilla.org/en/docs/Web/API/MediaDevices/getUserMedia [`systemPreferences.getMediaAccessStatus`]: system-preferences.md#systempreferencesgetmediaaccessstatusmediatype-windows-macos ## Caveats ### Linux `desktopCapturer.getSources(options)` only returns a single source on Linux when using Pipewire. PipeWire supports a single capture for both screens and windows. If you request the window and screen type, the selected source will be returned as a window capture. --- ### MacOS versions 14.2 or higher `NSAudioCaptureUsageDescription` Info.plist key must be added in-order for audio to be captured by `desktopCapturer`. If instead you are running electron from another program like a terminal or IDE then that parent program must contain the Info.plist key. This is in order to facillitate use of Apple's new [CoreAudio Tap API](https://developer.apple.com/documentation/CoreAudio/capturing-system-audio-with-core-audio-taps#Configure-the-sample-code-project) by Chromium. > [!WARNING] > Failure of `desktopCapturer` to start an audio stream due to `NSAudioCaptureUsageDescription` permission not present will still create a dead audio stream however no warnings or errors are displayed. As of electron `v39.0.0-beta.4` Chromium [made Apple's new `CoreAudio Tap API` the default](https://source.chromium.org/chromium/chromium/src/+/ad17e8f8b93d5f34891b06085d373a668918255e) for desktop audio capture. There is no fallback to the older `Screen & System Audio Recording` permissions system even if [CoreAudio Tap API](https://developer.apple.com/documentation/CoreAudio/capturing-system-audio-with-core-audio-taps) stream creation fails. If you need to continue using `Screen & System Audio Recording` permissions for `desktopCapturer` on macOS versions 14.2 and later, you can apply a chromium feature flag to force use of that older permissions system: ```js // main.js (right beneath your require/import statments) app.commandLine.appendSwitch('disable-features', 'MacCatapLoopbackAudioForScreenShare') ``` --- ### MacOS versions 12.7.6 or lower `navigator.mediaDevices.getUserMedia` does not work on macOS versions 12.7.6 and prior for audio capture due to a fundamental limitation whereby apps that want to access the system's audio require a [signed kernel extension](https://developer.apple.com/library/archive/documentation/Security/Conceptual/System_Integrity_Protection_Guide/KernelExtensions/KernelExtensions.html). Chromium, and by extension Electron, does not provide this. Only in macOS 13 and onwards does Apple provide APIs to capture desktop audio without the need for a signed kernel extension. It is possible to circumvent this limitation by capturing system audio with another macOS app like [BlackHole](https://existential.audio/blackhole/) or [Soundflower](https://rogueamoeba.com/freebies/soundflower/) and passing it through a virtual audio input device. This virtual device can then be queried with `navigator.mediaDevices.getUserMedia`.