Author: Cyrus Wong (黃俊彥) — Google Developer Expert - Cloud (AI), Senior Lecturer at HKIIT

1. Problem Statement: Breaking Two Hard Ceilings in Lecture Hall Broadcasting & Post-Lecture Publishing

When broadcasting a live coding demonstration to a 30-to-80 student lab or up to a 600-seat multi-cohort lecture hall—and publishing the recorded 3-hour lecture with multilingual closed captions to YouTube Studio afterward—conventional web architectures hit two catastrophic walls:

The WebRTC 6-Peer CPU Wall & Firebase Anonymous Auth 100/hr NAT IP Ceiling :

Peer-to-peer WebRTC screen sharing encodes a separate VP8/H.264 video stream per connected viewer ($O(N)$ CPU complexity), pegging the presenter's laptop CPU at 100% after just 6–8 students.

Worse, when dozens of students in a lecture hall scan a live broadcast QR code while connected to the same campus Wi-Fi NAT gateway IP, calling signInAnonymously() immediately triggers Firebase Auth's hard 100-signups-per-hour-per-IP rate limit ( auth/too-many-requests ),…