SpeedUpSI

SpeedUp

A native iOS video speed editor built with Swift and SwiftUI. Pick videos from your Photos library, preview them at adjustable playback speeds, and export time-scaled copies — with audio — back to your library.

Features

• Video picker — Select videos from your Photos library via PhotosUI, with iCloud streaming support
• Looping preview — Seamless looping playback using AVQueuePlayer and AVPlayerLooper
• Custom speed picker — Horizontal scroll control (0.1x–10x) with drag gestures, momentum-based snapping, and tick marks at every 0.1x increment
• Video + audio export — Time-scales both video and audio tracks independently using AVMutableComposition, preserving sync at any speed
• Export progress — Real-time progress bar with polling during export
• Save to Photos — Exported videos are saved directly back to the Photos library
• Animated splash screen — Custom Shape-based lightning bolt animation with staggered easing
• Accessibility — Full VoiceOver support on the speed picker (accessibilityAdjustableAction), semantic colors for dark/light mode, Dynamic Type support
• Loading states — Indeterminate spinner for streaming, determinate progress bar for file transfers
• Long video warning — Alert for videos over 5 minutes before starting export

Tech Stack

Technology	Usage
Swift / SwiftUI	UI layer, state management, navigation
AVFoundation	AVQueuePlayer, AVPlayerLooper, AVMutableComposition, AVAssetExportSession
PhotosUI	PhotosPicker for native Photos library access
Photos	PHImageManager, PHPhotoLibrary for asset fetching and saving
CoreMedia	CMTime arithmetic for time-scaling composition tracks
UniformTypeIdentifiers	Transferable conformance for video file handling

Architecture

SpeedUPSIApp            → App entry point
├── SplashView          → Animated launch screen (transitions to ContentView)
└── ContentView         → Main screen: video player, speed controls, export
    ├── VideoView       → AVQueuePlayer wrapper with looping and speed binding
    ├── SpeedPicker     → Custom horizontal scroll speed selector
    └── VideoSlot       → State-driven card (empty → uploading → ready)

State management: Local @State properties in ContentView with @Binding passed to child views.

Export pipeline: AVMutableComposition → insert video + audio tracks → scaleTimeRange by 1/speed → AVAssetExportSession at highest quality → save to Photos library → clean up temp file.

Project Structure

SpeedUPSI/
├── SpeedUPSIApp.swift      # App entry point
├── ContentView.swift        # Main view, video loading, export engine, Photos fetchers
├── SpeedPicker.swift        # Custom horizontal scroll speed picker
├── SplashView.swift         # Animated splash screen with LightningBolt shape
├── VideoSlot.swift          # VideoState enum and state-driven card component
├── Info.plist               # App configuration
└── Assets.xcassets/         # App icon and asset catalog

SpeedUPSITests/
└── SpeedUPSITests.swift     # Unit tests (speed label formatting, VideoState, time-scaling math)

Build & Run

1. Open SpeedUPSI.xcodeproj in Xcode
2. Select an iOS Simulator or physical device
3. Build and run (Cmd + R)

No external dependencies or package managers required.

Testing

xcodebuild test -scheme SpeedUPSI -destination 'platform=iOS Simulator,name=iPhone 15'

Tests cover:

• cleanSpeedLabel() — trailing zero stripping and decimal formatting
• VideoState enum — all cases construct correctly
• Time-scaling math — verifies CMTime arithmetic at 0.25x, 0.5x, 1x, 2x, and 10x speeds

License

This project is part of a personal 90-day iOS + AI learning challenge.