Audio API

The OTR (Over-The-Radio) communication stack is built to function across a wide range of hardware—from high-power Windows systems to lightweight Raspberry Pi nodes—while delivering secure, efficient, and hardware-accelerated audio streaming and rendering. To achieve this, we rely on:

DirectX (Windows Validator Nodes)

  • Purpose: Powers low-latency, high-fidelity audio relay from SDR devices like Hermes, Apache Labs, and Thetis.
  • Why: DirectX is tightly integrated into Windows, offering native access to audio buffers, lower overhead than ffmpeg, and direct compatibility with Thetis SDR software.
  • Impact: Eliminates the need for buggy third-party audio bridges like Mumble. Ensures stable playback, lower CPU use, and better integration with wallet and validator UI.

OpenGL (Raspberry Pi & Portable Nodes)

  • Purpose: Handles audio visualization, light UI rendering, and secure waveform relays on low-power devices.
  • Why: OpenGL is cross-platform and supported natively by Pi GPU hardware, making it ideal for offline, headless, or field deployments.
  • Impact: Keeps the Pi fast and cool while still supporting real-time audio relay, waveform preview, or secure storage of audio logs to IPFS.

Benefits for OTR Validators and SDR Operators:

  • ✅ Fully offline-capable audio relay
  • ✅ Compatible with both Thetis sdr stack and standalone nodes
  • ✅ Supports MAC-authenticated routing and IPFS-based playback
  • ✅ Works with 3D print alerts, SafeSignal messages, or HF voice logging

API Overview

POST /audio/start

Starts audio capture and relay stream.

json{
  "deviceId": "default",
  "streamTo": "validator://MAC_ADDRESS",
  "format": "pcm" 
}

POST /audio/stop

Stops the current audio stream.

json{
  "sessionId": "stream-12345"
}

GET /audio/status/:sessionId

Check relay status or connection integrity.

Node Security

  • Audio relays are only permitted from nodes with verified MAC addresses
  • All audio logs can be optionally published to IPFS for audit or playback
  • Relays are logged to the CID ledger, ensuring accountability and traceability

Use Cases

  • 📻 SDR → Validator audio (e.g., Hermes, Apache Labs)
  • 🧾 Secure field logs or voice memos
  • 🛰️ Remote signal relay from field validators