Whelm Voice Server

High-performance voice relay and instant messaging server for the Whelm/Aerochat platform.

Features

• Voice Calling: 48kbps Opus audio relay (96kbps both ways)
• Instant Messaging: Real-time message routing with MariaDB persistence
• Live Status: Heartbeat-based online/offline status tracking
• Bandwidth Limiting: Configurable 100Mbps up/down limits
• Capacity Planning: ~400 simultaneous calls max

Resource Requirements

Based on my 6 vCPU, 12GB RAM, 275mbps down / 225mbps up Debian server:

Resource	Allocation	Notes
CPU	1-2 vCPU	Go is efficient, mostly I/O bound
RAM	~100MB	Minimal memory footprint
Storage	10MB binary	+ logs if enabled
Bandwidth	100/100 Mbps	Self-limited, configurable

Max Capacity Calculation

Audio bitrate: 48 kbps per direction
Per call (server relay): 96kbps in + 96kbps out = 192 kbps
Bandwidth limit: 100 Mbps = 100,000 kbps
Max theoretical calls: 100,000 / 192 ≈ 520 calls
With 20% safety margin: ~400 simultaneous calls

Installation (Debian)

Prerequisites

sudo apt update
sudo apt install golang-go mariadb-client

Build from source

git clone https://github.com/YOUR_USER/voiceMt.git
cd voiceMt
go build -o whelm-voice-server .

Or download from GitHub Releases

wget https://github.com/YOUR_USER/voiceMt/releases/latest/download/whelm-voice-server-linux-amd64
chmod +x whelm-voice-server-linux-amd64
mv whelm-voice-server-linux-amd64 /usr/local/bin/whelm-voice-server

Configuration

Set environment variables before running:

export WHELM_DB_DSN="whelm:yourpassword@tcp(db.example.com:3306)/whelm?parseTime=true"

Running

Direct

./whelm-voice-server

As systemd service

sudo cp whelm-voice.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable whelm-voice
sudo systemctl start whelm-voice

Protocol

TCP Signaling (Port 5000)

Commands (newline-terminated):

Command	Description
AUTH <token>	Authenticate with session token
HEARTBEAT [status]	Keep-alive, optionally update status
CALL <user_id>	Initiate call to user
ACCEPT <caller_id>	Accept incoming call
REJECT <caller_id>	Reject incoming call
HANGUP	End current call
MSG <recipient_id> <content>	Send instant message

Server responses:

Response	Description
OK AUTH <user_id> <username>	Auth successful
OK HEARTBEAT	Heartbeat acknowledged
OK CALLING <user_id>	Call request sent
INCOMING <caller_id> <username>	Incoming call notification
START_CALL <partner_id> <username>	Call connected
REJECTED <user_id>	Call was rejected
HANGUP <user_id>	Call ended by other party
MSG <json>	Incoming message
ERROR <message>	Error occurred

UDP Voice Relay (Port 5001)

1. Register with: HELLO <user_id>
2. Send Opus packets directly (server relays to call partner)

Database Schema

Uses existing Whelm users and messages tables:

-- users table must have: id, username, session_token, status, last_seen
-- messages table must have: id, sender_id, channel_id, content, timestamp