LosslessCut (MP4)

LosslessCut (MP4) is a high-performance, open-source Android application for instant, lossless media trimming and merging. By manipulating compatible codecs (H.264, H.265, AAC) directly, it preserves original quality and processes files at lightning speed, remuxing them into standard .mp4 and .m4a containers without re-encoding.

✨ Key Feature Pillars

⚡ Zero-Loss Direct Bitstream Engine

• 🚀 Direct Muxing: Trims and merges video (.mp4) and audio (.m4a) using native MediaExtractor and MediaMuxer with zero transcoding.
• 📦 Batch Export & Merge: Export multiple "KEEP" regions as individual clips or merge them into a single seamless file in one pass.
• 🎼 Smart Audio Extraction: Automatically routes audio-only exports to lossless .m4a files in the Music folder.
• 🔄 Rotation Metadata & Quick Fixes: Apply orientation/rotation flag repairs without re-encoding.

🧰 Unified Editor Workflow

• 📥 One Entry Point: Load video or audio from the redesigned dashboard and use the same editor for trimming, splitting, rotation, and export.
• 🕘 Recent Sessions: Dirty editing sessions can be resumed from the dashboard while source access remains available through Android's Storage Access Framework.
• 🎛️ Export media surface: Choose combined or separate output, rotation metadata, and tracks from one full-screen modal.

🎞️ Pro NLE Timeline & Ergonomics

• 🔍 Precision Timeline: Zoom up to 20x for frame-accurate edits with mandatory keyframe snapping and haptic feedback.
• 👆 Anchored Actions: Long-press inside a segment to split or delete at the touch location; non-destructive Undo/Redo history stack.
• 📱 Adaptive Layout: Responsive landscape sidebar, floating player overlay, and audio waveform display.
• ♿ Accessibility First: Full screen-reader support via ExploreByTouchHelper virtual view hierarchies.

🤖 Smart Cut (v2.0) Automated Detection

• 🔇 Silence Cut: Automated detection and removal of quiet sections with interactive ghost state preview and incremental +/- step slider controls.
• 👁️ Visual Detection: pHash, SAD luminance delta, and contrast-normalized Laplacian variance for Scene, Black, Freeze, and Blur detection.
• 🔀 Invert Keep/Discard: Instantly toggle between removing or preserving detected ranges.

🔒 Privacy, SAF & Performance Cache

• 📂 Scoped Storage: Storage Access Framework (SAF) tree output and MediaStore integration with zero unnecessary permissions.
• ⚡ Analysis Cache: App-private LRU cache for waveforms and visual analysis with configurable size caps and retention age.
• 🛡️ 100% Offline: Zero analytics, zero data collection, zero network permissions.

📸 Screenshots

🛠️ How it Works

Unlike traditional video editors that decode and re-encode every frame, LosslessCut operates at the container level:

1. Probe: Scans file bitstreams to extract stream metadata, tracks, and sync keyframes.
2. Visualize: Renders a zoomable NLE timeline where keyframes act as mandatory snapping boundaries.
3. Mux: Writes original encoded sample buffers directly to the target output container.

🚀 Getting Started

Using the app

1. Tap Load media and choose one or more compatible video or audio files.
2. Edit the loaded media in the timeline using trim, split, rotate, Smart Cut, and undo/redo actions.
3. Tap Export to choose combined or separate output, adjust rotation metadata, select tracks, and export the edited media.
4. Leave the editor with unsaved changes to keep a recent session card on the dashboard; completed exports and discarded sessions are removed from recents.

Prerequisites

• JDK 17 or 21
• Android SDK 36 (Target) / 26 (Min)
• AGP 9.0+ / Gradle 9.2+

Development & Build

# Clone the repository
git clone https://github.com/tazztone/losslesscut-android.git
cd losslesscut-android

# Build debug APK
./gradlew assembleDebug

# Deploy and launch on connected device
./scripts/dev-scripts/adb-run-app.sh

Downloads

Prebuilt APK and AAB artifacts are published with tagged releases on GitHub Releases.

🤝 Contributing

We follow MVVM + Clean Architecture with strict layer separation between UI, Domain, and Data modules.

• Multi-Module: Core logic belongs in :core:domain, :core:data, or :engine.
• Use Cases: All business logic MUST reside in Use Cases within :core:domain.
• Verification: Run ./scripts/dev-scripts/project-verify.sh before submitting PRs.

🛡️ Security Policy

If you discover a security vulnerability, please report it privately to the maintainers rather than opening a public issue.

🗺️ Roadmap

• Smart Cut (v2.0): Integrated visual detection (Scene, Black, Freeze, Blur) with Silence Cut.
• Architectural Enforcement: Konsist tests safeguarding module boundaries.
• Domain Purification: Standard pure JVM domain module (:core:domain).
• Modern Build: Full migration to Gradle Kotlin DSL and AGP 9.0.
• Advanced Tags: Title, artist, and creation date editing (container-specific metadata writer).

📚 Documentation Index

For detailed technical specifications, architecture blueprints, domain model glossaries, and developer workflows:

• 🏗️ Architecture & Technical Reference: System architecture, multi-module structure, component blueprints, reactive state flow, risk tiers, and format matrix.
• 📖 Domain Model & Glossary: Ubiquitous domain language, aggregate boundaries (EditingSession), and smart cut entities.
• 🛠️ Contributing Guide: Development setup, script automation suite, CI verification pipeline, and GitHub Actions release secrets management (gh cli).
• ⚙️ Build Tooling Matrix: Toolchain versions (AGP, Gradle, Kotlin, KSP), flags, and modernization roadmap.
• 🔒 Privacy Policy: Storage Access Framework (SAF) privacy model.

📄 License

Licensed under the MIT License. See LICENSE for details.