EdgeCaster RTSP Gateway

EdgeCaster is a local edge gateway that pulls Rhombus Secure Raw Streams (H.264 over HTTPS) and re-broadcasts them as standard RTSP on your local network using bundled MediaMTX. It runs on a Raspberry Pi 5, a mini-PC, or any Ubuntu/Debian machine, so legacy VMS, NVR, and third-party AI/video systems that require RTSP can consume video from Rhombus cameras with sub-second added latency. You manage it from a simple web dashboard; it runs 24/7 and heals itself when a stream drops.

How it works

Rhombus Camera
     │
     │ Secure Raw Stream (HTTPS H.264)
     ▼
EdgeCaster (Raspberry Pi 5 / mini-PC / Ubuntu-Debian machine)
     │ FFmpeg stream copy (no transcoding)
     ▼
MediaMTX (RTSP server, port 8554)
     │
     ▼
External Systems (VMS / NVR / AI)

EdgeCaster uses the Rhombus API to discover cameras, creates secure raw streams via createRawHttpStream, and pipes them through FFmpeg (stream copy — no transcoding) to MediaMTX, which serves them as standard RTSP.

Sub-second latency, always the latest frame

Because streams are copied rather than transcoded (-c copy), there is no decode/encode delay. EdgeCaster minimizes latency by stripping buffering at every hop instead:

• FFmpeg runs with no input buffering, low-delay flags, reduced probe/analyze time for fast startup, and zeroed mux delay and preload, so packets are forwarded the instant they arrive. The tunables (probe size, analyze duration, stall threshold) are exposed in /etc/edgecaster/config.yaml if you need to adjust them on-device.
• MediaMTX is tuned for low latency and fast failure detection: its control API is enabled on localhost, and a short read timeout drops a stalled publisher quickly. Each RTSP reader gets its own queue, so a slow consumer cannot add latency to the publisher or to other readers.

The result: EdgeCaster always pushes the newest frame with sub-second added latency inside the device. End-to-end ("glass-to-glass") latency also depends on the camera's GOP/keyframe interval and your consuming system's own buffer, which EdgeCaster doesn't control.

Unlimited concurrent streams

There is no fixed stream limit — the device runs as many streams as its network and CPU allow. Because stream copy is very light, real-world testing on a Raspberry Pi 5 showed a handful of 1080p streams plus multiple RTSP readers at roughly 3% CPU, leaving large headroom. max_streams: 0 (the default) means unlimited; set a positive value in config.yaml if you want an optional hard safety ceiling.

24/7 self-healing

EdgeCaster monitors each stream at the frame level using FFmpeg's progress output — not just "is the process alive" — so a frozen-but-alive feed (no new frames) is detected within seconds by a watchdog. All failure triggers (process exit, frozen feed, dead process) funnel through one recovery path that guarantees exactly one relaunch, with no double-restart races. Recovery re-fetches a fresh Secure Raw Stream URL from Rhombus (stream tokens expire) and resumes, typically within seconds.

If a stream keeps failing, EdgeCaster retries fast (every 5 seconds, up to 10 times), then backs off to every 5 minutes — and keeps trying forever. It never permanently gives up on a 24/7 device. Frozen-feed recovery uses a lighter, faster backoff.

Features

• Sub-second added latency, always-latest-frame restreaming (stream copy, no transcoding)
• Unlimited concurrent streams — as many as your device's network and CPU allow
• 24/7 self-healing with frame-level stall detection and automatic stream URL refresh
• Live health dashboard with real-time metrics over Server-Sent Events
• Webhook alerts for stream drops and device strain (Slack, Make.com, or any HTTP listener)
• Live logs viewer in the dashboard — no SSH needed
• Optional one-click secure public access via a Cloudflare quick tunnel
• Automatic camera discovery via the Rhombus API
• Persistent stream state across reboots; streams auto-restore on startup
• Nightly auto-updates, a one-line installer, and a ready-to-flash Raspberry Pi image

Requirements

Install

curl -fsSL https://raw.githubusercontent.com/RhombusSystems/edgecaster-stream-converter/main/scripts/bootstrap.sh | sudo bash

git clone https://github.com/RhombusSystems/edgecaster-stream-converter.git
cd edgecaster-stream-converter
sudo bash scripts/install.sh

# Cloud-init mode (smaller image, needs internet on first boot)
sudo bash image/build-image.sh

# Pre-baked mode (larger image, no internet needed on first boot)
sudo bash image/build-image.sh --prebaked

Set up (2 minutes)

1. Open the dashboard

   Open EdgeCaster in a web browser: http://edgecaster.local or http://<device-ip>.

2. Paste your Rhombus Org API Key

   Your cameras appear automatically.

3. Toggle a camera on

   Flip the switch next to any camera to start its RTSP stream.

4. Connect your systems

   Copy the camera's RTSP link into your VMS, NVR, or AI system:

   rtsp://<device-ip>:8554/front_door
   rtsp://<device-ip>:8554/warehouse
   rtsp://<device-ip>:8554/parking_lot

   Camera names are normalized to URL-safe slugs and persisted, so RTSP paths survive reboots. Test with VLC: vlc rtsp://<device-ip>:8554/<stream-name>

Web dashboard

The dashboard is a clean, responsive operator console that works on any device or browser — on mobile, the sidebar becomes a drawer. A persistent status pulse (live stream count and a health dot) is always visible in the top bar.

Live health metrics

The dashboard streams metrics live (about once per second) over Server-Sent Events — no manual refresh: active streams, cameras found, CPU %, memory %, temperature, power/throttle status (under-voltage and throttling), 1-minute load average, uptime, and per-stream throughput and reader counts.

Webhook alerts

EdgeCaster can send an alert to a generic webhook — a Slack incoming webhook, Make.com, or any HTTP listener — when:

• A stream drops or can't recover
• The Pi reports under-voltage (power constrained)
• The Pi reports thermal throttling
• CPU or load average stays high

Thresholds are configurable, each alert has a cooldown, and alerts clear on recovery so the webhook isn't spammed. Set it up under Settings → Alerts, which includes a Send test alert button. Active alerts also show on the dashboard.

Live logs

A Logs tab (under Cameras) shows the device's logs live in a terminal-style console — useful for diagnosing a camera or connection issue without SSH:

• Sources: Application, Streams, and Rhombus API
• New lines stream in live, with color-coded log levels
• Pause and clear controls

Public access (optional)

To reach the dashboard from outside your network, go to Settings → Public Access, set a username and password, and click Turn on public access. EdgeCaster creates a secure public link via a Cloudflare quick tunnel and shows it. No Cloudflare account, token, or configuration is required.

The access model: on your local network you never log in; the public link always requires the username and password. Only traffic arriving over the public tunnel is challenged (HTTP Basic auth); the password is stored hashed, never in plaintext.

Public access requires the cloudflared helper, which the installer includes.

Network ports

Rhombus API endpoints used

EdgeCaster interacts with 5 Rhombus API endpoints automatically:

Managing services

EdgeCaster runs as systemd services (edgecaster and mediamtx) with watchdog integration. Enabled cameras and their RTSP slugs persist across reboots, and streams auto-restore on startup.

# Check status
sudo systemctl status edgecaster mediamtx

# View logs
journalctl -u edgecaster -f

# Restart
sudo systemctl restart edgecaster

# Update now (also runs nightly on its own)
sudo bash /opt/edgecaster/scripts/edgecaster-update.sh

# Uninstall
sudo bash /opt/edgecaster/scripts/uninstall.sh

Auto-updates

EdgeCaster checks for updates hourly and applies them (git fast-forward) during a configurable window (default: 2:00–5:00 AM). All install methods auto-update, including manual git-checkout installs. Configure via the web UI Settings page or directly:

# /etc/edgecaster/config.yaml
auto_update_enabled: true
update_hour_start: 2
update_hour_end: 5

Configuration

Configuration lives in /etc/edgecaster/config.yaml; runtime state (enabled cameras and RTSP slugs) lives in /var/lib/edgecaster/state.json; logs live in /var/log/edgecaster/. Notable keys:

# /etc/edgecaster/config.yaml
max_streams: 0               # 0 = unlimited (default); positive value = hard ceiling
stall_threshold_seconds: 6   # frozen-feed detection threshold
ffmpeg_probesize: 500000     # lower = faster startup
ffmpeg_analyzeduration: 1000000
alerts_enabled: false
alert_webhook_url: ""
cpu_alert_threshold: 85      # percent, sustained
temp_alert_threshold_c: 80
load_alert_threshold: 0      # 1-min load average; 0 = disabled

Local development

python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
cd backend
uvicorn app.main:app --reload --host 0.0.0.0 --port 8000

cd frontend
npm install
npm run dev
# Dev server on http://localhost:5173, proxies /api to backend

pip install pytest pytest-asyncio
python -m pytest backend/tests/ -v

EdgeCaster API

The EdgeCaster backend exposes a local REST API:

Limitations

• RTSP authentication is not enabled in v1 — restrict access via network controls (can be added via MediaMTX config)
• Consuming systems must be on the local network — RTSP is not tunneled by public access
• Secure raw stream tokens expire automatically; EdgeCaster re-fetches them on recovery
• No login on the LAN web UI — trusted network deployment only (public access adds a login for the public tunnel only)

Security notes

• Your API key is stored in /etc/edgecaster/config.yaml (owned by the edgecaster user, not world-readable)
• API keys are never logged or exposed in API responses
• The systemd service runs with hardened security: NoNewPrivileges, ProtectSystem=strict, ProtectHome, PrivateTmp
• RTSP streams are unauthenticated — restrict port 8554 access at the network level
• With public access on, only tunnel traffic is challenged with HTTP Basic auth; the password is stored hashed (never plaintext) and LAN traffic is never challenged

Troubleshooting

Need help?

Email support@rhombus.com and we'll help you get set up. It helps to include what you were doing and anything shown on the dashboard.

Resources