AudioPeel

🎵 AudioPeel

**中文

English**

A lightweight Android video-to-audio extraction tool, supporting MP3 / M4A / WAV / FLAC / OGG output — ad-free and completely free

📸 Screenshots

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📋 Table of Contents

• Features
• Tech Stack
• Build Guide
• Development Notes
• Permissions
• Contributing
• License

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🌟 Features

• Simple Video Selection — Native Android Photo Picker support. No storage permissions required.

• Multiple Output Formats — Export to MP3, M4A, WAV, FLAC, or OGG, covering everything from high-compatibility lossy to lossless formats.

• Smart Format Detection — Automatically detects the embedded audio codec and selects the optimal output format (e.g., AAC→M4A), prioritizing direct stream copy for instant extraction.

• Blazing Fast Extraction — SAF direct read skips file copying, smart stream copy avoids unnecessary transcoding, and multi-threaded processing leverages multi-core performance. An 18-minute video takes just seconds.

• Real-time Progress — Circular progress bar with percentage readout, with cancel support at any time.

• Built-in Audio Preview — Smooth playback powered by Media3 ExoPlayer with silky seek bar interaction.

• File Management — Custom renaming, auto-save to /Music/AudioPeel, and one-tap access via system file manager.

• Quick Sharing — Secure file sharing via FileProvider to WeChat, Telegram, and other apps.

• Minimal APK Size — R8 code shrinking + resource shrinking + ABI filtering for the smallest possible install size.

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🚀 Tech Stack & Architecture

Built following Google’s recommended modern architecture practices, entirely with native solutions:

Module	Technology
Language	100% Kotlin
UI Framework	Jetpack Compose + Material Design 3 + Edge-to-Edge
Media Processing	FFmpegKit (com.mrljdx:ffmpeg-kit-full)
Audio Engine	AndroidX Media3 ExoPlayer
Media Probing	Native MediaExtractor + MediaMetadataRetriever
Architecture	MVVM + StateFlow unidirectional data flow
File Storage	Scoped Storage + MediaStore API (Android 10+ compatible)
Size Optimization	R8 shrinking + resource shrinking + ABI filter (arm64-v8a, x86_64)

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💻 Build Guide

Prerequisites

1. Android Studio (Iguana

   2023.2.1 or later recommended)

2. Java 11+ (must be compatible with Gradle version)
3. Android SDK Level 36+ (Target SDK API 36 recommended)

Compatibility: Minimum Android 7.0 (API 24), Target SDK API 36.

Build Steps

1. Clone the repository:

   git clone https://github.com/tianxing-ovo/AudioPeel.git
   

2. Open the project root directory in Android Studio.
3. Wait for Gradle to sync and download dependencies.
4. Connect a physical device or configure an Android emulator.
5. Click Run 'app' or execute ./gradlew assembleDebug in the terminal.

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💡 Development Notes

Throughout the development of this project, we tackled several common challenges in Android’s fragmented ecosystem. We hope these insights help other developers facing similar issues:

• SAF Direct Read — Using FFmpegKitConfig.getSafParameterForRead() to read videos directly from content:// URIs, completely eliminating the time-consuming step of copying files to a cache directory. Separate SAF file descriptors are allocated for FFprobe and FFmpeg to resolve the SAF id not found issue.

• Smart Stream Copy — Detecting the source audio codec via native MediaExtractor. When the codec is compatible with the target format, -c:a copy is used to directly copy the audio stream, avoiding unnecessary transcoding for near-instant extraction.

• Cross-version Storage Compatibility — Unified support across multiple Android generations: Android 10+ uses MediaStore.Audio.Media.EXTERNAL_CONTENT_URI for secure writes; transitional versions use Documents Provider to locate the Music folder; legacy devices use traditional file creation.

• MD3 Interaction Polish — Redesigned Slider and ExoPlayer controls to resolve the progress bar snap-back jitter caused by concurrent background media progress updates and user drag events in Jetpack Compose, achieving smooth, damped iOS-like interaction.

• APK Size Reduction — R8 code shrinking + resource shrinking + ABI architecture filtering. The private directory is automatically cleaned before each extraction to prevent unbounded data growth.

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🔒 Permissions

This app follows the principle of least privilege and requires no sensitive permissions:

Permission	Description
No Storage Permission	Uses Android Photo Picker for video selection — no READ_EXTERNAL_STORAGE needed
No Network Permission	All processing is done locally — no data is uploaded
No Background Permission	No background execution or notification permissions requested

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🤝 Contributing

Issues and Pull Requests are welcome!

1. Fork this repository
2. Create a feature branch: git checkout -b feature/your-feature
3. Commit your changes: git commit -m "feat: add your feature"
4. Push the branch: git push origin feature/your-feature
5. Open a Pull Request

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📜 License

This project is open-sourced under the MIT License. Feel free to clone, learn from, share, and build upon it.

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