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The stack uses a pipeline architecture where audio flows from your studio through several processing stages before reaching listeners.

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Signal flow

Studio (BUTT/etc)
   ├── MP3 320k stream ──► :8010 ─┐
   └── MP3 192k stream ──► :8011 ─┤
                              ▼
                      ┌─────────────┐
                      │  Liquidsoap  │──► HLS segments
                      │  (encoding + │
                      │   fallback)  │
                      └──────┬───────┘
                             │
                      ┌──────▼───────┐
                      │   Icecast2   │  6 mount points
                      └──────┬───────┘
                             │
                      ┌──────▼───────┐
                      │    Nginx     │  :80 / :443
                      │  HLS + proxy │
                      └──────────────┘

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Components

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Liquidsoap

The core audio processor. It:
  • Accepts two incoming studio streams (primary on port 8010, fallback on port 8011)
  • Manages the three-tier fallback chain: primary, fallback, emergency file
  • Encodes audio into six Icecast output formats (MP3, AAC, Ogg Vorbis at multiple bitrates)
  • Generates HLS adaptive bitrate segments with three AAC quality tiers
  • Detects silence and triggers alerts

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Icecast2

Distributes audio to listeners over HTTP. Provides six mount points for different format and bitrate combinations. The Icecast admin panel gives you raw listener statistics and mount point status.

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Nginx

The public entry point. It:
  • Terminates SSL with Let’s Encrypt certificates
  • Reverse-proxies Icecast mount points under /listen/
  • Serves HLS segments under /hls/
  • Proxies the status panel API under /api/
  • Proxies the Icecast admin interface under /icecast-admin/

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Status Panel

A Flask API that provides:
  • Live listener counts and mount point health
  • Docker container status monitoring
  • Emergency audio file upload and management
  • Appwrite team-based authentication with role-based write access

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Analytics

A Python service that:
  • Polls Icecast statistics at a configurable interval
  • Sends listener and stream events to PostHog
  • Sends Pushover alerts for silence, outages, and failovers

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Certbot

Handles automatic Let’s Encrypt certificate provisioning and renewal.

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Fallback chain

The stack uses a three-tier fallback chain that activates automatically with no manual intervention:
  1. Primary stream — your main studio feed (port 8010, MP3 320 kbps)
  2. Fallback stream — a backup studio feed (port 8011, MP3 192 kbps)
  3. Emergency file — a local MP3 file at emergency-audio/fallback.mp3
When the primary stream disconnects, Liquidsoap switches to the fallback stream within seconds. If both studio feeds are offline, the emergency audio file loops until a stream reconnects. All transitions are handled by Liquidsoap and are seamless for listeners.