Vissper OSS

Real-time speech-to-text transcription for macOS with AI-powered transcript polishing. Built with Rust and native macOS frameworks.

Overview

Vissper OSS is an open-source desktop application that captures microphone audio and transcribes it in real-time using Azure OpenAI’s Realtime API. It runs discretely in the macOS menu bar with a transparent overlay window for live transcription display.

Key highlights:

• Direct connection to Azure OpenAI (no intermediary servers)
• Native macOS UI via objc2 bindings to AppKit
• Real-time WebSocket streaming for instant transcription
• Secure credential storage in macOS Keychain

Features

Transcription

• Real-time speech-to-text via Azure OpenAI Realtime API (GPT-4o Transcribe)
• Multi-language support: English, Norwegian, Danish, Finnish, German
• Live partial and final transcript display
• Automatic reconnection with retry logic

AI-Powered Polishing

• Basic Polish: Copyediting for grammar and readability
• Meeting Notes: Structured summaries with action items, decisions, and key points
• Preserves original language and meaning

User Interface

• Menu bar integration (NSStatusBar)
• Transparent overlay window that floats above other applications
• Multi-tab view: Raw transcript, Basic polish, Meeting notes
• Customizable transparency and appearance

Screenshot Integration

• Full-screen and region-based screenshot capture
• Screenshots embedded in transcripts as markdown images
• Timestamped filenames for organization

Export Options

• Copy to clipboard (automatic on stop)
• Save as Markdown files
• Export to PDF

Requirements

• macOS 12.0+ (Monterey or later)

• Azure OpenAI account with:

• GPT-4o Transcribe deployment (for speech-to-text)

• GPT-4o or similar deployment (for polishing)

• Rust toolchain (latest stable) - Install Rust

Quick Start

1. Clone and Build

git clone https://github.com/vissper/vissper-oss.git
cd vissper-oss
cargo build --release

2. Run

cargo run --release

Or run the binary directly:

./target/release/vissper

3. Configure Azure OpenAI

1. Click the Vissper icon in the menu bar
2. Select Settings
3. Enter your Azure OpenAI credentials:

• Endpoint URL: https://your-resource.openai.azure.com
• STT Deployment: Your GPT-4o Transcribe deployment name
• Polish Deployment: Your GPT-4o deployment name
• API Key: Your Azure OpenAI API key

1. Click Save

Credentials are stored securely in the macOS Keychain.

4. Start Recording

• Click Start Recording in the menu bar, or
• Press Control + Space (global hotkey)

Keyboard Shortcuts

Shortcut	Action
Control + Space	Start/Stop recording (raw transcript)
Control + Shift + 1	Stop with basic polishing
Control + Shift + 2	Stop with meeting notes
Control + Shift + 0	Full-screen screenshot
Control + Shift + 9	Region screenshot

Project Structure

vissper-oss/
├── src/
│   ├── main.rs                    # Application entry point
│   ├── audio/                     # CoreAudio microphone capture
│   │   ├── mod.rs                 # Audio capture implementation
│   │   ├── types.rs               # AudioChunk, AudioCaptureHandle
│   │   └── resampler.rs           # 16kHz resampling
│   ├── menubar/                   # macOS menu bar (NSStatusBar)
│   │   ├── mod.rs                 # Menu bar manager
│   │   ├── builder.rs             # Menu item construction
│   │   ├── delegate.rs            # Objective-C delegate
│   │   ├── state.rs               # App state and callbacks
│   │   └── updates/               # Dynamic menu updates
│   ├── transcription_window/      # Transparent overlay window
│   │   ├── mod.rs                 # Window manager
│   │   ├── window.rs              # Window creation/layout
│   │   ├── state.rs               # Tab types, window state
│   │   ├── components/            # UI components
│   │   └── api/                   # Public window APIs
│   ├── recording/                 # Recording session management
│   │   ├── mod.rs                 # Start/stop logic
│   │   ├── transcription_task.rs  # Background transcription
│   │   ├── polish.rs              # Transcript polishing
│   │   └── clipboard.rs           # Clipboard operations
│   ├── transcription/             # Azure OpenAI Realtime API
│   │   ├── mod.rs                 # TranscriptionClient
│   │   ├── azure_connection.rs    # WebSocket management
│   │   └── azure_messages.rs      # Message serialization
│   ├── azure_openai.rs            # Azure OpenAI Chat API client
│   ├── keychain.rs                # macOS Keychain storage
│   ├── settings_window/           # Settings UI
│   ├── hotkeys.rs                 # Global keyboard shortcuts
│   ├── screenshot.rs              # Screenshot capture
│   ├── storage.rs                 # Local file storage
│   └── preferences.rs             # User preferences
├── config.toml                    # Application configuration
├── Cargo.toml                     # Rust dependencies
└── README.md

Architecture

┌─────────────────────────────────────────────────────────────┐
│                     Vissper (Rust + objc2)                  │
├─────────────────────────────────────────────────────────────┤
│  Menu Bar          │  Transcription Window  │  Settings     │
│  (NSStatusBar)     │  (NSWindow overlay)    │  (NSWindow)   │
├────────────────────┴───────────────────────┴────────────────┤
│                     Recording Manager                        │
├─────────────────────────────────────────────────────────────┤
│  Audio Capture     │  Transcription Client  │  Polish API   │
│  (CoreAudio)       │  (WebSocket)           │  (REST)       │
├────────────────────┴───────────────────────┴────────────────┤
│                   Azure OpenAI Services                      │
│         Realtime API (STT)    │    Chat API (Polish)        │
└─────────────────────────────────────────────────────────────┘

Data Flow

1. Audio Capture: CoreAudio captures microphone input, resampled to 16kHz mono PCM
2. Streaming: Audio chunks sent via WebSocket to Azure OpenAI Realtime API
3. Transcription: Partial and final transcripts received in real-time
4. Display: Transcripts shown in transparent overlay window
5. Polishing: On stop, optionally polish via Azure OpenAI Chat API
6. Output: Copy to clipboard and save to local storage

Development

Build Commands

# Development build
cargo build

# Release build (optimized)
cargo build --release

# Run tests
cargo test

# Lint
cargo clippy --all-targets --all-features

# Format code
cargo fmt

Key Dependencies

Category	Crate	Purpose
Async	tokio	Async runtime
HTTP	reqwest	REST API client
WebSocket	tokio-tungstenite	Realtime API
Audio	cpal, rubato	Capture and resampling
macOS UI	objc2, objc2-app-kit	Native AppKit bindings
Security	security-framework	Keychain integration
Hotkeys	global-hotkey	System-wide shortcuts

Thread Safety

All AppKit operations must run on the main thread. The codebase uses MainThreadMarker to prove main thread execution:

if let Some(mtm) = MainThreadMarker::new() {
// On main thread - safe to call AppKit
Self::update_ui(mtm);
} else {
// Dispatch to main thread
dispatch::Queue::main().exec_async(|| {
if let Some(mtm) = MainThreadMarker::new() {
Self::update_ui(mtm);
}
});
}

Configuration

config.toml

[version_check]
url = "https://vissper.com/version.json"
enabled = true

User Preferences

Stored in ~/.config/Vissper/preferences.json:

• Language preference
• Transcript/screenshot storage paths
• Overlay transparency (0.3-1.0)

Azure Credentials

Stored securely in macOS Keychain under service com.vissper.desktop.

Azure OpenAI Setup

1. Create an Azure OpenAI resource in the Azure Portal
2. Deploy the required models:

• GPT-4o Transcribe - for real-time speech-to-text
• GPT-4o (or similar) - for transcript polishing

1. Copy your API key from the Azure Portal
2. Enter credentials in Vissper Settings

Security

• Azure credentials stored in macOS Keychain (encrypted)
• No data sent to Vissper servers (direct Azure connection)
• Audio and transcripts stored only locally
• Sensitive data cleared from memory using zeroize
• No API keys or credentials in code or logs

License

Dual licensed under MIT and Apache 2.0. See LICENSE-MIT and LICENSE-APACHE.

Contributing

Contributions welcome! Please read CONTRIBUTING.md before submitting pull requests.

Support

• GitHub Issues - Bug reports and feature requests
• Discussions - Questions and community support