Problem Statement

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Video Conferencing System - Problem Statement

Overview

Design a video conferencing platform like Zoom that supports high-quality audio/video calls, screen sharing, recording, and can scale to support millions of concurrent meetings with participants distributed globally.

Functional Requirements

Core Video Conferencing

  • Audio/Video Calls: Support 1-on-1 and group video calls with HD quality
  • Screen Sharing: Share entire screen, specific windows, or applications
  • Chat Integration: Text messaging during video calls
  • Recording: Record meetings with audio, video, and screen sharing
  • Meeting Controls: Mute/unmute, camera on/off, participant management

Meeting Management

  • Scheduled Meetings: Create meetings with calendar integration
  • Instant Meetings: Start impromptu meetings immediately
  • Meeting Rooms: Persistent virtual rooms with custom URLs
  • Waiting Rooms: Control participant entry with host approval
  • Breakout Rooms: Split large meetings into smaller groups

Advanced Features

  • Virtual Backgrounds: AI-powered background replacement
  • Noise Cancellation: Real-time audio enhancement
  • Live Transcription: Real-time speech-to-text conversion
  • Polls and Q&A: Interactive meeting features
  • Whiteboard: Collaborative drawing and annotation tools

Platform Support

  • Web Browser: WebRTC-based browser support
  • Desktop Apps: Native Windows, macOS, Linux applications
  • Mobile Apps: iOS and Android applications
  • Room Systems: Integration with conference room hardware

Non-Functional Requirements

Performance

  • Latency: <150ms end-to-end audio/video latency
  • Video Quality: Support up to 4K resolution, adaptive bitrate
  • Audio Quality: 48kHz sampling rate, noise cancellation
  • Frame Rate: 30fps minimum, 60fps for screen sharing
  • Concurrent Meetings: Support 10M+ simultaneous meetings

Scalability

  • Meeting Size: Support up to 1000 participants per meeting
  • Global Scale: Serve users across all continents
  • Peak Load: Handle 100M+ concurrent participants
  • Storage: Petabytes of recorded meeting data
  • Bandwidth: Optimize for various network conditions (56kbps to 1Gbps)

Reliability

  • Uptime: 99.99% availability (4.38 minutes downtime/month)
  • Fault Tolerance: Graceful degradation during network issues
  • Recovery: Automatic reconnection within 5 seconds
  • Redundancy: Multi-region deployment with failover

Security

  • End-to-End Encryption: AES-256 encryption for all media streams
  • Authentication: Multi-factor authentication support
  • Access Control: Meeting passwords, waiting rooms, host controls
  • Compliance: GDPR, HIPAA, SOC 2 compliance
  • Privacy: No permanent storage of unrecorded meetings

Real-time Constraints

Media Streaming

  • Jitter Buffer: <50ms for smooth playback
  • Packet Loss: Handle up to 5% packet loss gracefully
  • Adaptive Bitrate: Adjust quality based on network conditions
  • Echo Cancellation: Real-time audio processing <20ms delay

Synchronization

  • Audio-Video Sync: Maintain <40ms lip-sync accuracy
  • Screen Share Sync: Synchronize screen updates across participants
  • Chat Sync: Deliver messages within 100ms
  • Participant State: Real-time updates for mute/video status

Network Optimization

  • Bandwidth Adaptation: Dynamic quality adjustment
  • Network Resilience: Handle network switching (WiFi to cellular)
  • Firewall Traversal: STUN/TURN servers for NAT traversal
  • CDN Integration: Edge servers for media relay

Cross-Platform Support

Web Platform

  • WebRTC: Native browser support without plugins
  • Browser Compatibility: Chrome, Firefox, Safari, Edge
  • Progressive Web App: Offline capabilities and app-like experience
  • Responsive Design: Adapt to various screen sizes

Native Applications

  • Desktop: Optimized native apps with system integration
  • Mobile: Battery-optimized mobile applications
  • API Consistency: Unified experience across platforms
  • Platform Features: Calendar integration, notifications, file access

Hardware Integration

  • Conference Rooms: Integration with room systems
  • Cameras: Support for external cameras and PTZ controls
  • Audio Devices: Professional microphones and speakers
  • Touch Displays: Interactive whiteboard integration

Success Metrics

User Experience

  • Join Time: <10 seconds from click to video
  • Connection Success: >99.5% successful meeting joins
  • Audio Quality: <1% audio dropouts
  • Video Quality: <2% video freezes or artifacts

Business Metrics

  • Concurrent Users: Support 100M+ peak concurrent users
  • Meeting Duration: Average 45-minute meetings
  • User Retention: >90% monthly active user retention
  • Global Coverage: <200ms latency in 95% of locations worldwide

Technical Metrics

  • CPU Usage: <30% CPU usage on client devices
  • Memory Usage: <500MB RAM usage per meeting
  • Battery Life: <20% battery drain per hour on mobile
  • Network Usage: Adaptive bandwidth 50kbps to 3Mbps per participant