Emyn

Emyn is a macOS virtual camera app for presenting yourself, app windows, media, and live captions as a single configurable camera feed. It captures a physical camera, removes or replaces the background, composites window captures or media into the output, and publishes the rendered frames through a Core Media IO camera extension.

• Physical camera capture with selectable input quality.
• Virtual camera output through EmynVirtualCameraExtension.
• Person segmentation with configurable quality, analysis resolution, mask blur, smoothing, and mask reuse.
• Background replacement with solid colors, blur, image/video media, or captured app windows.
• Multi-window selection, ordering, fitting, alignment, cycling, and direct window-control forwarding.
• Presentation controls for output resolution, horizontal/vertical flip, NTSC effect presets, zoom, cursor emphasis, image overlays, and confetti.
• Function-key shortcuts for live presentation actions.
• Presentation notes sidebar.
• Local speech-to-text configuration for caption styling, microphone selection, and downloadable GGUF models.

• macOS 14 or newer.
• Xcode with macOS development tools.
• Rust toolchain with rustup for rebuilding the macOS platform XCFramework.
• Apple developer signing setup for installing the virtual camera system extension outside local unsigned development.

The app uses camera, microphone, screen recording, accessibility, input monitoring, and system extension permissions depending on which features are enabled.

• Emyn/ - SwiftUI views, app lifecycle, permission flows, and adapters between package APIs.
• EmynVirtualCameraExtension/ - Core Media IO system extension that exposes the generated frames as a virtual camera.
• Packages/WindowCaptureKit/ - Window discovery, preview/stream capture, mouse and keyboard forwarding, and pointer-coordinate mapping.
• Packages/TranscriptionKit/ - Microphone capture, model catalog/download management, and local speech transcription.
• Packages/BackgroundRemovalKit/ - Vision person segmentation, temporal smoothing, and reusable render-mask generation.
• Packages/VideoCompositionKit/ - Camera input, backgrounds, filters, captions, effects, frame composition, and output publishing.
• Packages/SharedFrameKit/ - The memory-mapped frame contract shared by the composition pipeline and virtual-camera extension.
• platform-macos/ - Rust macOS platform layer, UniFFI bindings, ScreenCaptureKit/window-control support, input forwarding, and NTSC processing.
• platform-macos/swift/PlatformMacOSKit/ - Generated Swift package and XCFramework consumed by the app.
• transcribe-cpp-swift/ - Local Swift package for speech-to-text integration.
• EmynPerformanceTests/ - Swift package tests for performance-sensitive sizing and render gate logic.
• tools/ - Development harnesses.

For Xcode Product > Archive from a fresh checkout, run this once first:

./transcribe-cpp-swift/scripts/update-xcframework.sh

To pin a version:

./transcribe-cpp-swift/scripts/update-xcframework.sh v0.1.1

Open Emyn.xcodeproj in Xcode and build the Emyn scheme.

If you change the Rust platform layer, rebuild the Swift XCFramework first:

./platform-macos/scripts/build-xcframework.sh

Then build from the command line:

xcodebuild -project Emyn.xcodeproj -scheme Emyn -configuration Debug -destination 'platform=macOS' build

For release packaging, the repository includes:

./release.sh --build-only

Use ./release.sh --help for signing, notarization, and XCFramework options.

The package graph and performance-sensitive helpers can be tested through Swift Package Manager:

swift test

See docs/package-architecture.md for package dependencies and examples of reusing an individual package from another app.

To reset the permission system:

tccutil reset ScreenCapture com.stylemac.Emyn

Emyn is available under the MIT License. See LICENSE.