second-display/README.md

Second Display

A native macOS app that shows video from a capture device (capture card, camera) in a window and plays audio from a chosen input — a "second monitor".

Requirements

macOS 26+, Xcode (Command Line Tools).

Build and run

make          # builds build/SecondDisplay.app
make run      # build and launch
make check    # lint: typecheck, plists, translations, signature
make install  # copy to ~/Applications
make help     # list targets

The app is signed ad-hoc (works on this Mac). For distribution: make SIGN_ID="Developer ID Application: ..." (notarization is still required).

Usage

Menus at the top of the screen: Video (device, format), Audio (source or off), Options (prevent display sleep, start in full screen, always on top, mute ⇧⌘M, scaling), Window (tiling, full screen ⌃⌘F).

Layout

• Sources/ – the app (AppKit + AVFoundation): App (state, window), Capture (devices, formats), Menu, Power, Preferences, main (entry point)
• Config/ – Info.plist, entitlements (camera, microphone)
• Resources/ – icon (AppIcon.icon, Icon Composer), en/pl translations, uninstall.sh
• scripts/check-strings.sh – translation consistency

Settings and uninstall

Settings: ~/Library/Preferences/com.mmacierzanka.seconddisplay.plist. To remove the app and all its traces: make uninstall or SecondDisplay.app/Contents/Resources/uninstall.sh.