Voice Bridge

A server-side Paper plugin that bridges proximity voice chat between Simple Voice Chat and Plasmo Voice, allowing players using different voice mods to hear each other.

How it works

Both Simple Voice Chat (SVC) and Plasmo Voice (PV) encode audio with Opus at 48 kHz, mono, 20 ms frames. Voice Bridge intercepts audio packets from each mod's API and relays them to the other — no transcoding required. The result is low-latency, cross-mod proximity voice chat with minimal CPU overhead.

SVC Player ──► SVC API ──► Voice Bridge ──► PV API ──► PV Player
PV Player  ──► PV API  ──► Voice Bridge ──► SVC API ──► SVC Player

Requirements

• Paper 1.21.4+ (or Folia)
• Java 21+
• Simple Voice Chat (server-side plugin)
• Plasmo Voice (server-side plugin)

Installation

1. Install both Simple Voice Chat and Plasmo Voice on your Paper server
2. Download voice-bridge-<version>.jar
3. Place it in your server's plugins/ directory
4. Restart the server

Building from source

./gradlew build

The plugin jar will be in build/libs/.

Running a dev server

# With Mojang mappings (for debugging)
./gradlew runDevBundleServer

# With obfuscation (production-like)
./gradlew runServer

Configuration

A config.yml is generated on first run in plugins/voice-bridge/:

bridge:
  enabled: true       # Enable/disable the bridge
  debug: false        # Enable debug logging

proximity:
  default-distance: 48.0      # Default voice range in blocks
  whisper-multiplier: 0.33    # Whisper range = distance * multiplier
  max-distance: 128.0         # Maximum allowed voice distance

audio:
  passthrough: true            # Opus passthrough (recommended)
  force-transcode: false       # Force transcoding (not yet implemented)

Per-world distance overrides

You can override the default voice distance for specific worlds:

proximity:
  world-overrides:
    world_nether: 24.0
    world_the_end: 64.0

Commands

Command	Description
/voicebridge status	Show bridge status, metrics, and config
/voicebridge players	List active bridged sessions
/voicebridge reload	Reload configuration
/voicebridge debug [on|off]	Toggle debug logging

Alias: /vb

Permission: voicebridge.admin (default: op)

Architecture

┌────────────────────────────────────────────────┐
│              VoiceBridgePlugin                 │
├───────────┬───────────┬────────────┬───────────┤
│ SvcAdapter│ PvAdapter │ AudioRelay │  Session  │
│           │           │            │  Manager  │
├───────────┴───────────┴────────────┴───────────┤
│  SpatialMapper │ BridgeConfig │ BridgeMetrics  │
└────────────────────────────────────────────────┘

• SvcAdapter — integrates with Simple Voice Chat via VoicechatPlugin
• PvAdapter — integrates with Plasmo Voice via @Addon / AddonInitializer
• AudioRelay — central router that forwards audio frames between adapters
• SessionManager — tracks which mod each player is using
• SpatialMapper — converts between SVC float distances and PV short distances

Known limitations

• Group/channel bridging is not supported (proximity chat only)
• Transcoding mode is not yet implemented (passthrough only)
• SVC-only players may not receive audio from PV players in some edge cases