BeEvent

BeEvent is an iOS camera app that converts ordinary iPhone camera frames into simulated event-camera style photos and videos.

It does not capture real hardware event-camera data. It simulates event output from conventional camera frames on device.

Positive events render red, negative events render blue, and no-event pixels render black.

Requirements

• macOS with Xcode installed
• iOS 17+
• XcodeGen
• Real iPhone for final camera verification

Setup

./scripts/bootstrap.sh
open BeEvent.xcodeproj

Test

./scripts/test.sh

Source Layout

• BeEvent/: iOS app source.
• BeEvent/Features/Camera: SwiftUI camera UI, preview, controls, and Docs.
• BeEvent/Features/Capture: AVFoundation session and frame pipeline.
• BeEvent/Infrastructure/Permissions: camera, microphone, and photo-library permissions.
• BeEvent/Infrastructure/Export: event photo/video export and Photos saving.
• EventCore/: event simulation, rendering, and Metal processing.
• EventCore/Tests: deterministic EventCore tests.
• Icons/: source assets for generated app icon.
• scripts/: bootstrap, test, and asset-generation scripts.

Product Contract

• On-device media processing only.
• No accounts.
• No analytics.
• No ads.
• No tracking.
• No uploads.
• No network access.
• No location permission.
• Do not store, save, export, or transmit raw RGB camera frames.
• Normal user saves go to Photos as simulated event photos/videos.
• Temporary save-staging files are deleted after successful Photos insertion.
• Event polarity is always red for positive, blue for negative, and black for none.

Simulation Modes

Selectable modes:

• Basic Frame Difference
• Log Intensity DVS
• Accumulated DVS
• v2e Inspired
• Stylized Event

Basic Frame Difference is the default mode at app launch and after non-persistent state reset.

Every selectable mode must use the optimized Metal/Core Video path for live preview, photo capture, video recording, and export. CPU simulation may exist only as deterministic test/reference code that the app runtime cannot call.

Camera UI

The main screen is a real camera UI, not a mock:

• Full-screen event preview
• Photo/Video toggle
• Centered shutter
• Lower-right front/back camera switch
• Zoom slider
• Simulation mode picker
• Mode-specific Parameters dropdown for controls such as thresholds, intensity, accumulation, and v2e-inspired settings
• Preview resolution picker
• Background RGB camera FPS picker when supported
• Lower-left Photos affordance
• Permission fallback UI
• Centered recording timer in video mode
• Bilingual English/Japanese in-app Docs

During active video recording, configuration-changing controls are hidden and disabled. Zoom and the front/back camera switch remain available unless a platform limitation requires truthful disabling.

App Icon

The app icon is generated from Icons/BeEvent_icon_gray.png by scripts/generate_app_icon.py.

The generator creates a 1024 x 1024 opaque PNG in the app icon asset catalog using Basic Frame Difference, a 4.8 px subpixel shift per copy, an 11/255 luminance threshold, and black/red/blue quantization.

Documentation

Primary implementation documents:

• AGENTS.md
• PRODUCT_REQUIREMENTS.md
• TECHNICAL_SPEC.md
• TASKS.md
• PRIVACY.md

These files are the source of truth for implementing the production app.