Intelligence meets a precise production engine.
Every part has a job: language plans the teaching, fixed geometry builds the scenes, and cloud workers deliver the film.
Claude Sonnet 5.5
The Anthropic API writes source-grounded teaching content and visual direction through structured schemas. Imported text is treated as evidence. The model cannot run shell commands or publish a course. Application validation checks citations, allowed fields and timing before production.
Three.js motion engine
Ten original templates use fixed 3D geometry, readable overlays and bounded camera movement. The renderer computes each frame from absolute time at 24 fps, keeping preview, seeking and exported video consistent. Numeric scenes bind displayed values to source facts.
Google Cloud narration
Gemini Flash TTS provides one male Charon voice. Speech is cached by narration, model and voice, then measured. CPU-based WhisperX alignment anchors captions to the actual audio; uncertain timing stays visible for review.
FFmpeg & Cloud Run
Cloud Run Jobs render scenes and encode the finished MP4. FFmpeg assembles complete narration, normalizes audio, adds caption tracks and prepares browser-friendly playback metadata. ffprobe and full-file decoding validate the output.
Firebase & private storage
Firebase authenticates accounts. The Google Cloud API verifies identity tokens and workspace permissions. Firestore stores source versions, production jobs, reviews, releases and learner progress. Original sources and generated artifacts remain in private Cloud Storage; authorized downloads use temporary URLs.
Durable jobs & cost controls
Cloud Tasks dispatches planning work with authenticated identity. A scheduled reconciler recovers missing handoffs. Paid calls reserve their conservative cost first. Lost acknowledgments are quarantined rather than blindly repeated. The current production workspace uses a $75 gross usage cap.
Vercel delivery
Vercel serves the website, interface, motion previews and the approved public course example. Private app requests reach the authenticated Google Cloud API. The public course example contains the approved film; creators keep their uploaded sources private.