1. Create client:     client = ZoomVideo.createClient()
2. Initialize:        await client.init('en-US', 'Global', options)
3. Join session:      await client.join(topic, signature, userName, password)
4. Get stream:        stream = client.getMediaStream()  ← ONLY AFTER JOIN
5. Start media:       await stream.startVideo() / await stream.startAudio()

// WRONG: Getting stream before joining
const stream = client.getMediaStream();  // Returns undefined!
await client.join(...);

// CORRECT: Get stream after joining
await client.join(...);
const stream = client.getMediaStream();  // Works!

// WRONG
const stream = client.getMediaStream();  // undefined!
await client.join(...);

// CORRECT
await client.join(...);
const stream = client.getMediaStream();  // Works

import { VideoQuality } from '@zoom/videosdk';

// CORRECT: attachVideo returns element to append
const videoElement = await stream.attachVideo(userId, VideoQuality.Video_360P);
document.getElementById('video-container').appendChild(videoElement);

// WRONG: renderVideo is deprecated
await stream.renderVideo(canvas, userId, ...);  // Don't use!

// When another participant's video state changes
client.on('peer-video-state-change', async (payload) => {
  const { action, userId } = payload;
  
  if (action === 'Start') {
    // Participant turned on video - attach it
    const element = await stream.attachVideo(userId, VideoQuality.Video_360P);
    container.appendChild(element);
  } else if (action === 'Stop') {
    // Participant turned off video - detach it
    await stream.detachVideo(userId);
  }
});

// When participants join/leave
client.on('user-added', (payload) => {
  // New participant joined - check if their video is on
  const users = client.getAllUser();
  // Render videos for users with bVideoOn === true
});

client.on('user-removed', (payload) => {
  // Participant left - clean up their video element
  stream.detachVideo(payload[0].userId);
});

// After joining, render existing participants' videos
const renderExistingVideos = async () => {
  await new Promise(resolve => setTimeout(resolve, 500));
  
  const users = client.getAllUser();
  const currentUserId = client.getCurrentUserInfo().userId;
  
  for (const user of users) {
    if (user.bVideoOn && user.userId !== currentUserId) {
      const element = await stream.attachVideo(user.userId, VideoQuality.Video_360P);
      document.getElementById(`video-${user.userId}`).appendChild(element);
    }
  }
};

function waitForSDK(timeout = 10000) {
  return new Promise((resolve, reject) => {
    if (typeof WebVideoSDK !== 'undefined') {
      resolve();
      return;
    }
    const start = Date.now();
    const check = setInterval(() => {
      if (typeof WebVideoSDK !== 'undefined') {
        clearInterval(check);
        resolve();
      } else if (Date.now() - start > timeout) {
        clearInterval(check);
        reject(new Error('SDK failed to load'));
      }
    }, 100);
  });
}

await waitForSDK();
const ZoomVideo = WebVideoSDK.default;

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp

const stream = client.getMediaStream();

// Check if 720p is supported
const hdSupported = stream.isSupportHDVideo();

// Get maximum video quality
const maxQuality = stream.getVideoMaxQuality();
// 0=90P, 1=180P, 2=360P, 3=720P, 4=1080P

// Start video with HD
if (hdSupported) {
  await stream.startVideo({ hd: true });
}

const stream = client.getMediaStream();

// Check which element type to use
if (stream.isStartShareScreenWithVideoElement()) {
  // Use video element
  const video = document.getElementById('share-video');
  await stream.startShareScreen(video as unknown as HTMLCanvasElement);
} else {
  // Use canvas element
  const canvas = document.getElementById('share-canvas');
  await stream.startShareScreen(canvas);
}

import { VideoQuality } from '@zoom/videosdk';

VideoQuality.Video_90P   // 0
VideoQuality.Video_180P  // 1
VideoQuality.Video_360P  // 2 (recommended for most cases)
VideoQuality.Video_720P  // 3
VideoQuality.Video_1080P // 4

const stream = client.getMediaStream();

// Always check support first
if (stream.isSupportVirtualBackground()) {
  // Blur background
  await stream.updateVirtualBackgroundImage('blur');
  
  // Custom image background
  await stream.updateVirtualBackgroundImage('https://example.com/bg.jpg');
  
  // Remove virtual background
  await stream.updateVirtualBackgroundImage(undefined);
}

// video-processor-worker.js
class MyVideoProcessor extends VideoProcessor {
  processFrame(input, output) {
    const ctx = output.getContext('2d');
    ctx.drawImage(input, 0, 0);
    
    // Add overlay
    ctx.fillStyle = 'white';
    ctx.font = '24px Arial';
    ctx.fillText('Live', 20, 40);
    
    return true;
  }
}

await client.init('en-US', 'Global', {
  patchJsMedia: true,
  webrtc: true  // Enable WebRTC mode
});

await stream.startVideo();
await stream.stopVideo();

await stream.startAudio();
await stream.muteAudio();
await stream.unmuteAudio();
await stream.stopAudio();

// Get available devices
const cameras = stream.getCameraList();
const mics = stream.getMicList();
const speakers = stream.getSpeakerList();

// Switch devices
await stream.switchCamera(cameraId);
await stream.switchMicrophone(micId);
await stream.switchSpeaker(speakerId);

// Start sharing
await stream.startShareScreen(canvas);

// Stop sharing
await stream.stopShareScreen();

// Receive share
client.on('active-share-change', async (payload) => {
  if (payload.state === 'Active') {
    await stream.startShareView(canvas, payload.userId);
  } else {
    await stream.stopShareView();
  }
});

const chatClient = client.getChatClient();

// Send to everyone
await chatClient.send('Hello, everyone!');

// Send to specific user
await chatClient.sendToUser(userId, 'Private message');

// Receive messages
client.on('chat-on-message', (payload) => {
  console.log(`${payload.sender.name}: ${payload.message}`);
});

const recordingClient = client.getRecordingClient();

await recordingClient.startCloudRecording();
await recordingClient.stopCloudRecording();

client.on('recording-change', (payload) => {
  console.log('Recording status:', payload.state);
});

// Leave session (others stay)
await client.leave();

// End session for ALL participants (host only)
await client.leave(true);

try {
  await client.join(topic, signature, userName, password);
} catch (error) {
  if (error.reason?.includes('signature')) {
    // Regenerate signature and retry
  } else if (error.reason?.includes('Session')) {
    // Show "Waiting for host..." and poll
  } else if (error.reason?.includes('Permission')) {
    // Guide user to enable permissions
  }
  console.error('Join failed:', error);
}

video-sdk/web/
├── SKILL.md                           # Main skill overview
├── SKILL.md                           # This file - navigation guide
│
├── concepts/                          # Core architectural patterns
│   ├── sdk-architecture-pattern.md   # Universal formula for ANY feature
│   └── singleton-hierarchy.md        # 4-level navigation guide
│
├── examples/                          # Complete working code
│   ├── session-join-pattern.md       # JWT auth + session join
│   ├── video-rendering.md            # attachVideo() patterns
│   ├── screen-share.md               # Send and receive screen shares
│   ├── event-handling.md             # Required events
│   ├── chat.md                       # Chat implementation
│   ├── command-channel.md            # Command channel messaging
│   ├── recording.md                  # Cloud recording control
│   ├── transcription.md              # Live transcription/captions
│   ├── react-hooks.md                # Official @zoom/videosdk-react library
│   └── framework-integrations.md     # Next.js, Vue/Nuxt, ZFG patterns
│
├── troubleshooting/                   # Problem solving guides
│   └── common-issues.md              # Quick diagnostic workflow
│
└── references/                        # Reference documentation
    ├── web-reference.md              # API hierarchy, methods, error codes
    └── events-reference.md           # All event types