SameCouch

Watch any movie together, in sync, while you see and hear each other. One shared link → same room → synchronized playback + webcam/mic.

This repo is a single Node app that provides everything:

• the generated front-end (static output in public/, editable source in src/index.source.html)
• your own WebRTC signaling (self-hosted PeerJS at /peerjs)
• a realtime control plane at /rt (room roster, play/pause sync, "who is talking", and chat)
• an admin dashboard at /admin (live people-count + chat monitoring)
• short-lived TURN credentials at /turn-credentials
• a protected, low-CPU MKV/opaque-link remuxer at /mkv-stream (FFmpeg stream-copy → fragmented MP4)
• an opt-in connection check (server latency, TURN reachability and bounded speed test)
• a room-synced watchlist with voting, exact-time reactions/bookmarks and an automatic evening recap

Privacy model — read this first

• Camera/microphone calls and files shared from a device are peer-to-peer and end-to-end encrypted (WebRTC, DTLS-SRTP). The operator cannot watch or listen to calls or inspect device-shared files.
• Chat and selected subtitle text are different. Chat is relayed and stored temporarily so that you can moderate it (e.g. spot illegal use). Subtitle text for a direct video URL is relayed and held in the active room's memory so late joiners receive it, but is not shown in the admin dashboard. Neither chat nor subtitle text is end-to-end encrypted. You become the controller of that data — see SECURITY.md and disclose it in your privacy policy. The app already shows users an in-room notice that chat messages may be reviewed.
• Remote MKV links use the low-CPU Node remuxer; opaque direct-video links may first try the browser when it reports full support. The Node fallback copies the original video packets into fragmented MP4 without re-encoding them. Film bytes then temporarily pass through FFmpeg, are not stored, and are not end-to-end encrypted from source host to viewer. Disclose this too.

Architecture at a glance

Browser  ──(audio/video, P2P, E2E encrypted)──  Browser     ← never hits the server
   │                                               │
   └───────── /rt (chat, subtitles, sync, talking) ───────┘
                         │
                    Node server  ── /peerjs (signaling)   ── /admin (monitor)
                         │         ── /turn-credentials
                         │
                    coturn (TURN relay, your VPS or managed)  ← media only when P2P fails

The diagram's P2P media path refers to calls and files shared from a device. A pasted MKV source follows source → Node/FFmpeg stream-copy → viewer. An opaque direct-video source can follow source → viewer only when the browser reports full support, as described below.

Multi-party uses a mesh (everyone connects to everyone). This is good for small groups (roughly up to 6–8 people). Beyond that you'd move to an SFU (e.g. mediasoup / LiveKit / Janus) — that's the scaling path, not a quick toggle.

Only one remote camera is shown at a time. It rotates every 2 minutes and switches immediately to whoever starts talking (with onset/hangover detection so brief noises don't cause false switches). You still hear everyone.

Deployment

Production is split over two hosts:

• Front-end — the static public/ folder is served by Vercel at samecouch.com (www.samecouch.com and the old watchmovietogether.com domains redirect there). Vercel deploys automatically on every push to main. Edit the root vercel.json; public/vercel.json is a generated copy (npm run build:frontend). Vercel cannot run the Node server.
• Backend — the Node server (server/server.js: room server/signaling, chat relay, IPTV gateway, remuxer, admin) runs on a virtual server from Netwise Hosting Ltd in London, UK, as the systemd unit samecouch.service in /opt/samecouch, with nginx terminating TLS in front of it. The coturn TURN relay runs on the same server. Config files are in deploy/vps/; secrets live only in /etc/samecouch.env on the server, never in this repo. Deploys are manual: copy the changed files to /opt/samecouch, run systemctl restart samecouch.service, then check that coturn is still active. The front-end reaches the backend through REMOTE_BACKEND in src/index.source.html.
• Data — the SQLite database is on that server. Encrypted nightly database backups go to a server at netcup GmbH in Germany and are kept 14 days; nginx access logs are kept 14 days. If you change hosts or retention, update public/privacy.html and public/privacy-nl.html too.

render.yaml is legacy: the Render service is no longer used.

Local development

npm install
ADMIN_PASSWORD=secret123 npm start
# open http://localhost:8080  (admin at http://localhost:8080/admin)

# regression checks (includes a two-user realtime room test)
npm test

# after editing src/index.source.html
npm run build:frontend

Camera/mic need https (or localhost). On a deployed host you're on https already.

Your own TURN (temporary credentials)

The server hands out short-lived TURN credentials (coturn's use-auth-secret HMAC scheme) at /turn-credentials. You just need a TURN server that shares the same secret.

This is the beginning of the README. Read the rest at the original. Read the full README ↗