Screen Capture and Media
Explore how to access screen capture capabilities, media devices, and integrate them into your Electron desktop applications.
Screen Capture and Media is a free Electron Desktop App Development lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Electron Desktop App Development learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Accessing Camera & Screen
Electron lets your desktop app use native features like cameras, microphones, and even capture the screen. This opens up possibilities for video calls, screen recording, and more!
We'll explore how to list available devices, display live camera feeds, and capture your desktop or specific windows.
Discovering Your Devices
Before using a camera or microphone, you can discover what's available on the user's system. The navigator.mediaDevices.enumerateDevices() method provides a list of all connected media input and output devices.
Run this code to see your devices. You might need to grant permission to access devices.
const { app, BrowserWindow } = require('electron');
function createWindow() {
const win = new BrowserWindow({
width: 600,
height: 450,
webPreferences: {
nodeIntegration: true,
contextIsolation: false // Simplifies example for A1. Use preload scripts for security in real apps.
}
});
const htmlContent = `
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Media Devices</title>
</head>
<body>
<h1>Available Media Devices</h1>
<ul id="device-list"></ul>
<script>
async function getMediaDevices() {
try {
const devices = await navigator.mediaDevices.enumerateDevices();
const list = document.getElementById('device-list');
if (devices.length === 0) {
list.innerHTML = '<li>No media devices found or permission denied.</li>';
return;
}
devices.forEach(device => {
const li = document.createElement('li');
li.textContent = `Kind: ${device.kind}, Label: ${device.label || 'Unknown'}`;
list.appendChild(li);
});
} catch (err) {
console.error('Error listing devices:', err);
document.getElementById('device-list').innerHTML = `<li>Error: ${err.message}</li>`;
}
}
getMediaDevices();
</script>
</body>
</html>
`;
win.loadURL(`data:text/html;charset=utf-8,${encodeURIComponent(htmlContent)}`);
}
app.whenReady().then(createWindow);
app.on('window-all-closed', () => app.quit());
app.on('activate', () => {
if (BrowserWindow.getAllWindows().length === 0) createWindow();
});Displaying Camera Stream
To display a live camera feed, we use navigator.mediaDevices.getUserMedia(). This method requests access to a media input device (like a camera) and, if granted, provides a MediaStream.
This stream can then be displayed in a <video> element. Try running this example:
const { app, BrowserWindow } = require('electron');
function createWindow() {
const win = new BrowserWindow({
width: 600,
height: 450,
webPreferences: {
nodeIntegration: true,
contextIsolation: false // Simplifies example for A1. Use preload scripts for security in real apps.
}
});
const htmlContent = `
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Camera Stream</title>
</head>
<body>
<h1>My Camera Feed</h1>
<video id="camera-feed" autoplay style="width:100%; height:auto;"></video>
<p id="status"></p>
<script>
async function startCamera() {
const video = document.getElementById('camera-feed');
const status = document.getElementById('status');
try {
const stream = await navigator.mediaDevices.getUserMedia({
video: true // Request video access
});
video.srcObject = stream;
status.textContent = 'Camera feed active.';
} catch (err) {
console.error('Error accessing camera:', err);
status.textContent = `Error: ${err.message}. Please grant camera permission.`;
}
}
startCamera();
</script>
</body>
</html>
`;
win.loadURL(`data:text/html;charset=utf-8,${encodeURIComponent(htmlContent)}`);
}
app.whenReady().then(createWindow);
app.on('window-all-closed', () => app.quit());
app.on('activate', () => {
if (BrowserWindow.getAllWindows().length === 0) createWindow();
});User Permissions & Errors
Accessing media devices like cameras and microphones requires explicit user permission. When getUserMedia() is called, the operating system will typically prompt the user for consent.
- Your application should always be ready to handle cases where the user grants or denies permission.
- Catching errors from
getUserMedia()(e.g.,NotAllowedError) helps you inform the user about permission issues.
Understanding DesktopCapturer
Electron provides the desktopCapturer module, a powerful tool that allows your app to capture video and audio from the entire screen, specific windows, or individual displays.
This is essential for building features like screen sharing, screen recording, or even taking screenshots of other applications running on the user's desktop.
Getting Screen Sources
To capture a screen or window, you first need to get a list of available sources. desktopCapturer.getSources() provides these, including their IDs, names, and even thumbnails.
This method is available in the renderer process (but usually exposed via a preload script for security). For simplicity in this lesson, we'll access it directly.
const { app, BrowserWindow } = require('electron');
function createWindow() {
const win = new BrowserWindow({
width: 600,
height: 450,
webPreferences: {
nodeIntegration: true, // Required for desktopCapturer
contextIsolation: false // Simplifies example for A1. Use preload scripts for security in real apps.
}
});
const htmlContent = `
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Screen Sources</title>
</head>
<body>
<h1>Available Screen Sources</h1>
<ul id="source-list"></ul>
<script>
const { desktopCapturer } = require('electron'); // Access desktopCapturer
async function getScreenSources() {
const list = document.getElementById('source-list');
try {
const sources = await desktopCapturer.getSources({
types: ['window', 'screen']
});
if (sources.length === 0) {
list.innerHTML = '<li>No screen or window sources found.</li>';
return;
}
sources.forEach(source => {
const li = document.createElement('li');
li.textContent = `ID: ${source.id}, Name: ${source.name}`;
if (source.thumbnail) {
const img = document.createElement('img');
img.src = source.thumbnail.toDataURL();
img.style.maxWidth = '100px';
img.style.marginLeft = '10px';
li.appendChild(img);
}
list.appendChild(li);
});
} catch (err) {
console.error('Error getting sources:', err);
list.innerHTML = `<li>Error: ${err.message}</li>`;
}
}
getScreenSources();
</script>
</body>
</html>
`;
win.loadURL(`data:text/html;charset=utf-8,${encodeURIComponent(htmlContent)}`);
}
app.whenReady().then(createWindow);
app.on('window-all-closed', () => app.quit());
app.on('activate', () => {
if (BrowserWindow.getAllWindows().length === 0) createWindow();
});Displaying a Screen Stream
Once you have a source ID (e.g., from a specific display or window), you can use navigator.mediaDevices.getUserMedia() again. This time, you pass a chromeMediaSource constraint with the desktopCapturer source ID.
This will capture the chosen screen/window and display it in a <video> element, similar to a camera feed.
const { app, BrowserWindow } = require('electron');
function createWindow() {
const win = new BrowserWindow({
width: 600,
height: 450,
webPreferences: {
nodeIntegration: true, // Required for desktopCapturer
contextIsolation: false // Simplifies example for A1. Use preload scripts for security in real apps.
}
});
const htmlContent = `
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Screen Capture</title>
</head>
<body>
<h1>Screen Capture Demo</h1>
<button id="start-capture">Start Screen Capture</button>
<video id="screen-feed" autoplay style="width:100%; height:auto;"></video>
<p id="status"></p>
<script>
const { desktopCapturer } = require('electron');
document.getElementById('start-capture').addEventListener('click', async () => {
const video = document.getElementById('screen-feed');
const status = document.getElementById('status');
status.textContent = 'Searching for sources...';
try {
const sources = await desktopCapturer.getSources({
types: ['screen'], // Only screens for simplicity
thumbnailSize: { width: 1, height: 1 } // No large thumbnails needed
});
if (sources.length === 0) {
status.textContent = 'No screen sources found.';
return;
}
// Take the first screen found
const screenSource = sources[0];
status.textContent = `Capturing: ${screenSource.name}`;
const stream = await navigator.mediaDevices.getUserMedia({
audio: false, // Can be true for audio
video: {
mandatory: {
chromeMediaSource: 'desktop',
chromeMediaSourceId: screenSource.id,
minWidth: 1280, minHeight: 720,
maxWidth: 1920, maxHeight: 1080
}
}
});
video.srcObject = stream;
status.textContent = 'Screen capture active.';
} catch (err) {
console.error('Error capturing screen:', err);
status.textContent = `Error: ${err.message}.`;
}
});
</script>
</body>
</html>
`;
win.loadURL(`data:text/html;charset=utf-8,${encodeURIComponent(htmlContent)}`);
}
app.whenReady().then(createWindow);
app.on('window-all-closed', () => app.quit());
app.on('activate', () => {
if (BrowserWindow.getAllWindows().length === 0) createWindow();
});Basic Media Recording
After getting a MediaStream (from a camera or screen), you can record it using the browser's MediaRecorder API. This lets you save the stream as a video or audio file.
The MediaRecorder takes the stream and collects data chunks, which can then be combined into a Blob (e.g., a video file).
const { app, BrowserWindow } = require('electron');
function createWindow() {
const win = new BrowserWindow({
width: 600,
height: 450,
webPreferences: {
nodeIntegration: true,
contextIsolation: false // Simplifies example for A1. Use preload scripts for security in real apps.
}
});
const htmlContent = `
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Media Recorder</title>
</head>
<body>
<h1>Simple Recorder</h1>
<button id="start-cam">Start Camera</button>
<button id="start-rec" disabled>Record</button>
<button id="stop-rec" disabled>Stop</button>
<video id="live-feed" autoplay muted style="width:100%; height:auto;"></video>
<a id="download-link" style="display:none;">Download Recording</a>
<p id="status"></p>
<script>
const startCamBtn = document.getElementById('start-cam');
const startRecBtn = document.getElementById('start-rec');
const stopRecBtn = document.getElementById('stop-rec');
const downloadLink = document.getElementById('download-link');
const liveFeed = document.getElementById('live-feed');
const status = document.getElementById('status');
let mediaRecorder;
let recordedChunks = [];
let currentStream;
startCamBtn.addEventListener('click', async () => {
try {
currentStream = await navigator.mediaDevices.getUserMedia({ video: true, audio: true });
liveFeed.srcObject = currentStream;
startRecBtn.disabled = false;
startCamBtn.disabled = true;
status.textContent = 'Camera ready. Click Record.';
} catch (err) {
status.textContent = `Error: ${err.message}`;
console.error('Error starting camera:', err);
}
});
startRecBtn.addEventListener('click', () => {
recordedChunks = [];
mediaRecorder = new MediaRecorder(currentStream);
mediaRecorder.ondataavailable = event => {
if (event.data.size > 0) {
recordedChunks.push(event.data);
}
};
mediaRecorder.onstop = () => {
const blob = new Blob(recordedChunks, { type: 'video/webm' });
const url = URL.createObjectURL(blob);
downloadLink.href = url;
downloadLink.download = 'electron-recording.webm';
downloadLink.style.display = 'block';
status.textContent = 'Recording stopped. Download available.';
};
mediaRecorder.start();
startRecBtn.disabled = true;
stopRecBtn.disabled = false;
status.textContent = 'Recording...';
});
stopRecBtn.addEventListener('click', () => {
mediaRecorder.stop();
startRecBtn.disabled = false;
stopRecBtn.disabled = true;
});
</script>
</body>
</html>
`;
win.loadURL(`data:text/html;charset=utf-8,${encodeURIComponent(htmlContent)}`);
}
app.whenReady().then(createWindow);
app.on('window-all-closed', () => app.quit());
app.on('activate', () => {
if (BrowserWindow.getAllWindows().length === 0) createWindow();
});Security Best Practices
When working with native media, always prioritize security. Granting access to cameras, microphones, or screen capture can be sensitive.
- Request Permissions Wisely: Only ask for permissions when absolutely necessary for your app's functionality.
- Inform Users: Clearly explain why your app needs access to these native features.
- Context Isolation & Preload Scripts: For real-world applications, use
contextIsolation: trueand exposedesktopCapturersecurely via a preload script. This prevents malicious scripts in the renderer from accessing Node.js APIs directly.
Quick Check: Native Media
Which of the following statements are true regarding accessing native media and screen capture in Electron?
Recap: Native Media
Great job! In this lesson, we explored how Electron applications can interact with native media features:
- We learned to use
navigator.mediaDevices.enumerateDevices()to list available cameras and microphones. - We accessed live camera feeds with
navigator.mediaDevices.getUserMedia(). - We discovered the
desktopCapturermodule for listing and capturing screen or window content. - We briefly touched upon using
MediaRecorderto save captured media streams. - Finally, we highlighted the importance of user permissions and security best practices when handling sensitive native features.
These tools empower you to build rich, interactive desktop applications with powerful media capabilities!
Frequently asked questions
Is the “Screen Capture and Media” lesson free?
Yes — the full text of “Screen Capture and Media” is free to read here on the web, and the Electron Desktop App Development course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Electron Desktop App Development course, upgrade to CoddyKit PRO.
What will I learn in “Screen Capture and Media”?
Explore how to access screen capture capabilities, media devices, and integrate them into your Electron desktop applications. You practise Electron Desktop App Development with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Electron Desktop App Development?
No prior experience is required. Electron Desktop App Development on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Screen Capture and Media” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Electron Desktop App Development lesson?
Yes. Every Electron Desktop App Development lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Working with Native Modules
- Tray Applications & Badges
- Screen Capture and Media
- Power and Hardware Monitoring