Simple Voice Online

Client-side Fabric addon for Simple Voice Chat: when the Minecraft server has no voice chat installed, addon users on that server can still talk to each other.

How it works

Voice goes peer-to-peer whenever possible:

SVC client ⇄ loopback bridge ⇄ P2P engine ══ direct UDP ══► other players
                                     ⇅ (fallback only)
                                  Go relay

• On joining a server, the mod waits ~5 s for a real SVC SecretPacket. If none arrives, it connects to the relay's WebSocket, joins a room keyed by the server address, and receives a shared room key plus the peer list.
• Peers exchange address candidates (local interfaces + relay-observed public address) and hole-punch a direct UDP path — the ICE approach with a compact custom protocol.
• Voice frames are Opus, sealed once per frame with the room key (AES-128-GCM) and sent directly to every punched peer. Pairs whose NATs defeat punching fall back to blind forwarding via the relay, which never touches crypto or audio.
• The local SVC client is pointed at an in-process loopback bridge, so all audio capture/playback is stock Simple Voice Chat.

If the server later turns out to have voice chat, SVC's real connection replaces the fallback automatically.

Settings

In-game settings screen: press O (rebindable, "Simple Voice Online" key category) or open it through ModMenu if installed. The screen shows the live connection status (state, peers and whether each one is direct or relayed) and offers a manual Reconnect button. All changes apply immediately.

When the relay connection fails or drops, the mod auto-reconnects with exponential backoff (5s, 10s, 20s, 40s, then 60s) until maxReconnectAttempts is exhausted.