Crate Structure

The crates/ directory contains the domain logic. Each crate has a single responsibility and zero dependencies on Tauri or the UI.

Overview

crates/
├── application/     # Orchestration & State Machine
├── audio/           # Capture, AGC, Resampling
├── bus/             # Zero-copy Audio Pipeline
├── context/         # OS Awareness (Active App, Mic State)
├── detect/          # Meeting App Logic
├── events/          # Shared Event Contracts (DTOs)
├── models/          # Model Registry & Downloads
├── parakeet/        # NVIDIA Parakeet Backend
├── sherpa/          # Sherpa-ONNX Backend
├── smart-turn/      # Semantic Endpointing
├── storage/         # SQLite Persistence
├── stt/             # Engine Traits & Abstractions
├── transcript/      # Data Structures
├── turn/            # Turn Detection Traits
└── vad/             # Silero VAD Integration

Core Components

bus

The nervous system. Delivers audio from recorder to consumers. Key feature: Uses Arc<[f32]> so audio is allocated once and shared across all consumers.

context

The senses. Aggregates system state to drive the context engine.

• Active App: Which window has focus?
• Mic State: Is a meeting app using the hardware?
• Mode: Derives intent (Dev, Meeting, Global).

stt

Defines the SttEngine trait. Infrastructure crates (sherpa, parakeet) implement this.

audio

Handles microphone capture and preprocessing:

• Resampling: rubato for high-quality sample rate conversion.
• AGC: Automatic gain control with soft-clipping.

vad

Wraps Silero VAD for voice activity detection.

Dependency Graph

application
    ├── bus
    ├── stt (trait only)
    ├── vad (trait only)
    └── turn (trait only)

sherpa
    └── stt (implements SttEngine)

parakeet
    └── stt (implements SttEngine)

The application crate never imports sherpa or parakeet directly—only their traits.