AudioCutter

AudioCutter is an Android-first audio trimmer that lets you import a clip, preview a selection, apply speed or codec tweaks, and export a polished file ready for ringtones, notifications or loops. It combines Jetpack Compose UX, FFmpegKit trimming, and lightweight AdMob monetization so the feature set stays focused and responsive.

Highlights

• Jetpack Compose + Material 3 for responsive mobile-only layouts with waveform preview, chip controls, and contextual dialogs.
• FFmpegKit-backed trimming + waveform generation with selectable output formats (MP3, AAC/M4A, OGG, FLAC and WAV), quality presets, and configurable speed.
• Integrated AdMob banner & interstitial hooks (keys live in app/build.gradle) so you can swap demo IDs with your production unit IDs.
• Easy-to-understand ViewModel state (AudioCutterViewModel) powering playback, trimming, waveform loading and user messaging.
• Sample assets such as autunno.mp3 (for test imports) and logo.jpeg for quick marketing/preview needs.

Getting started

1. Prerequisites

   • Java 17 (Coherent with the Gradle JVM defined in app/build.gradle).
   • Android SDK 35 (compile + target).
   • Android Studio Flamingo or newer if you want visual editing; otherwise the Gradle CLI via ./gradlew.
   • A local.properties file pointing to your SDK directory (Android Studio normally creates this automatically).

2. Clone & inspect

   git clone <repo-url>
   cd audio_cutter

   The Compose sources live under app/src/main/java/com/workwavestudio/audiocutter, resources under app/src/main/res, and the trimming logic inside AudioTrimProcessor.

3. Build and run

   • Run on emulator or device: ./gradlew installDebug (or open in Android Studio and hit the play button).
   • Assemble a ready-to-install APK: ./gradlew assembleRelease (release signing uses keystore.jks; rotate credentials for your production build).
   • Produce an AAB for Play Store: ./gradlew bundleRelease.

4. Testing

   • Unit tests: ./gradlew test
   • Instrumented/compose UI tests (requires device/emulator): ./gradlew connectedAndroidTest

5. Documentation

   • docs/USER_GUIDE.md: step-by-step instructions for end users and QA team expectations.
   • docs/DEVELOPER_GUIDE.md: environment setup, dependency notes, architecture overview, and release reminders.
   • docs/STORE_LISTING.md: ASO-friendly Play Store listing draft and keyword ideas.
   • docs/PRIVACY_POLICY.md: privacy policy text you can publish on your site.
   • docs/TERMS_OF_SERVICE.md: terms of service text for publishing.

App structure

• AudioCutterViewModel handles UI state, playback via MediaPlayer, trimming requests and waveform generation.
• AudioTrimProcessor copies the chosen audio to cache, invokes FFmpegKit for trimming and waveform data, and returns an Android Uri.
• Compose UI sits in app/src/main/java/com/workwavestudio/audiocutter/ui with the screen, helper cards, custom waveform canvas, and a small Ads interop view (BannerAd).
• AdMob keys are injected via BuildConfig fields defined inside app/build.gradle, which differentiates production vs debug IDs.
• res/strings.xml, colors.xml, and themes.xml drive the Material theming used across cards/buttons/focus states.
• Assets such as logo.jpeg and autunno.mp3 live in the repository root for easy reference.

Customization notes

• Keep your real AdMob units in admob.properties (gitignored). Copy admob.properties.example, populate the four keys for production (BANNER_AD_UNIT_ID, INTERSTITIAL_AD_UNIT_ID) and debug (BANNER_AD_UNIT_ID_DEBUG, INTERSTITIAL_AD_UNIT_ID_DEBUG), and keep the resulting file private—the build script loads these values automatically.
• To switch to your own AdMob credentials, update BANNER_AD_UNIT_ID and INTERSTITIAL_AD_UNIT_ID in the release and debug build types inside app/build.gradle.
• The FFmpeg dependency currently pulls com.moizhassan.ffmpeg:ffmpeg-kit-16kb:6.0.0. If you drop app/libs/ffmpeg-kit-16kb-libshine.aar in place, Gradle will use it to enable MP3 via libshine. You can also enable MP3 via libmp3lame (standalone NDK) by placing libmp3lame.so in app/src/main/jniLibs/<abi>/ and the lame.h header in app/src/main/cpp/include/lame/. Uncomment the local ffmpeg-kit-full-gpl-6.0-2.LTS.aar block if you prefer the full GPL build.
• Keep the keystore.jks file in a secure place and rotate the passwords before publishing; update the signing config if the keystore moves or the alias changes.

License

This project is available under the MIT license. See LICENSE for details.