MicioStudio

Native, ultra-light macOS screen recorder for YouTube tutorials. SwiftUI app + a portable Rust core linked via UniFFI. See SPEC.md for the contract and AGENTS.md for the rules.

Status: Phase 1 — native-Retina capture + clean HEVC export (no effects/zoom yet).

One-time setup

# Build tooling
brew install xcodegen ffmpeg     # xcodegen: generates the .xcodeproj; ffmpeg: ffprobe for gate checks

# Rust: cargo 1.89+ (Homebrew or rustup both work — the bindgen is embedded, no version skew)
cargo --version

# Stable dev code-signing identity (one-time). Without it the app is ad-hoc signed and
# every rebuild invalidates its Screen Recording / Accessibility grants — macOS then
# re-prompts forever and recording fails. This creates a self-signed identity the app
# is signed with (app/project.yml → CODE_SIGN_IDENTITY), so grants persist across rebuilds.
bash scripts/setup-dev-signing.sh

Requirements: macOS 14+ (developed on macOS 26 / Xcode 26 / Swift 6.3 / Apple Silicon).

Grant the app's permissions ONCE after the first launch; with the stable identity they survive rebuilds. If they ever get stuck (e.g. after switching signing), reset and re-grant: tccutil reset ScreenCapture dev.miciodev.MicioStudio (and Accessibility, Camera, Microphone).

Repo layout

core/      Rust workspace — event_log (Phase 1); zoom_engine/template/library (later). No system APIs.
app/       SwiftUI macOS app (project.yml → XcodeGen). UniFFI bindings land in app/Generated/ (gitignored).
scripts/   build-core.sh (build core + generate bindings), verify-phase1.sh (gate checks)
templates/ builtin .json templates (Phase 2)
docs/      PROMPT.md (full mega-prompt / narrative spec)

Build & test

# 1. Rust core: run the TDD suite
cargo test --manifest-path core/Cargo.toml

# 2. Build the Rust static lib + generate the Swift UniFFI bindings into app/Generated/
bash scripts/build-core.sh

# 3. Generate the Xcode project and build the app
cd app && xcodegen generate
xcodebuild -project MicioStudio.xcodeproj -scheme MicioStudio -configuration Debug build

Note: Xcode also runs scripts/build-core.sh as a pre-build phase, so the bindings stay current on every build. ENABLE_USER_SCRIPT_SANDBOXING is off so that script can read core/target and write app/Generated.

Phase 1 gate (manual)

1. Launch the app. Grant Camera and Microphone when prompted.
2. Grant Screen Recording and Accessibility in System Settings ▸ Privacy & Security, then relaunch (these grants do not apply to an already-running process).
3. Click Record, click around the screen for ~10s, click Stop.
4. The app writes the canonical separate streams to ~/Movies/MicioStudio/<timestamp>/: screen.mov, camera.mov, mic.caf, system.caf, events.jsonl (SPEC §5.1). It does NOT write a combined file — that throwaway preview is derived by the verify script below.
5. Verify (auto-selects the latest session; also builds the side-by-side combined.mov preview with ffmpeg):

   bash scripts/verify-phase1.sh "$(ls -1dt ~/Movies/MicioStudio/*/ | head -1)"

   Green when: screen.mov is HEVC at native display pixels, stream durations agree within 0.5s (no drift), audio is 48kHz, events.jsonl is non-empty, and — by eye in the generated combined.mov — the click action lines up with the audio.

Conventions

• TDD on the Rust core (test first). Git Flow (branch per phase, e.g. feat/phase-1-capture). Conventional Commits. Do not advance past a phase gate without review.