Roadmap
1. The Fundamentals
- What is WebRTC? A clear definition and why it's a game-changer for communication.
- WebRTC vs. WebSockets: Understanding the key difference: Peer-to-Peer (P2P) vs. Client-Server.
- The Three Core APIs: A high-level look at the main building blocks of any WebRTC application:
getUserMedia()
: Accessing cameras and microphones.
RTCPeerConnection
: Establishing the direct connection.
RTCDataChannel
: Sending arbitrary data (like text chat).
2. The Connection Lifecycle (The Tricky Part)
- Signaling: The "out-of-band" process of coordinating the connection. We'll see why we still need a server (like our WebSocket server!) to get things started.
- SDP (Session Description Protocol): The "what." How peers describe their media capabilities (e.g., "I can handle H.264 video and Opus audio").
- ICE (Interactive Connectivity Establishment): The "how." The process of finding the best possible network path between two peers.
- STUN & TURN Servers: Understanding the helper servers that are essential for navigating network complexities like NATs and firewalls.
3. Client-Side Implementation (JavaScript)
- Getting Local Media: Using
getUserMedia
to capture video and audio from your devices.
- Creating a Peer Connection: Setting up the
RTCPeerConnection
object.
- The Offer/Answer Flow: The step-by-step dance of creating an "offer" (from the caller) and an "answer" (from the callee) using SDP.
- Exchanging ICE Candidates: How peers share potential network paths to find one that works.
4. Building a Simple Application
- A Two-Person Video Chat: We'll walk through the complete code flow, combining signaling (with WebSockets) and WebRTC to build a basic video call application.
- Data Channels in Action: Adding a simple text chat alongside the video call using
RTCDataChannel
.