MP4 to MP3 Converter with AdMob — Flutter App (Android & iOS)

A complete, ready-to-publish Flutter source code that lets users pick any video from their phone and instantly convert it to a high-quality MP3 audio file — 100% offline, no internet required for conversion.

Powered by FFmpeg, monetized with Google AdMob (Banner + Interstitial ads), designed with Material 3, and built with clean Riverpod architecture. Just swap in your AdMob App ID, change the package name, add your keystore, and ship to the Play Store or App Store.

Who Is This For?

Developers who want to launch a monetized audio utility app fast without building from scratch
Freelancers looking for a solid, well-structured Flutter codebase with ads already wired up
Studios wanting a privacy-first, offline app with built-in Google AdMob revenue from day one

✅ Key Features

Core Conversion

Convert any MP4 (or any video) to MP3 — powered by FFmpeg Kit
Selectable bitrates: 96 kbps, 128 kbps, 192 kbps, 256 kbps, 320 kbps
Real-time conversion progress bar with live percentage
Cancel conversion at any time mid-process
Detects and alerts if the selected video has no audio stream

Google AdMob Monetization

Banner Ad — displayed persistently at the bottom of the main screen
Interstitial Ad — shown after each successful conversion for maximum revenue
Ads load and pre-cache in the background using a singleton AdService
Graceful fallback — if an ad fails to load, the app continues working without any crash or freeze
Auto-reloads the next interstitial immediately after one is dismissed or fails to show
Just replace the two test Ad Unit IDs in lib/services/ad_service.dart with your own live IDs

Smart File Management

Save to custom folder — user picks via Android Storage Access Framework
Fallback to Downloads folder if no custom folder is set
Automatic duplicate file handling (e.g. “song (1).mp3”, “song (2).mp3”)
Persistent folder permission across app restarts

Conversion History

Every converted file is automatically saved to a history list
Shows file name, duration, bitrate, file size and conversion date
Play converted MP3 directly in the app with a built-in audio player
Share or open files with any external app (music players, cloud storage, etc.)
Delete individual records or clear all history with one tap

⚙️ Settings & Customization

Change default save location from the Settings tab
Reset save location to the default Downloads folder
Toggle Dark / Light mode — manual override from the AppBar
Single seed color in main.dart controls the full Material 3 theme

Design & Architecture

Material 3 design system with adaptive dark and light themes
State management with Flutter Riverpod 2.x
Clean separation: screens/, services/, widgets/, providers/, models/
History persisted locally using SharedPreferences
No external backend, no Firebase required

What Is Included

✅ Full Flutter source code (Android + iOS)
✅ Google AdMob fully integrated — Banner & Interstitial ads ready to go
✅ AdService singleton — clean, reusable ad management class
✅ Native Android Kotlin code (MainActivity.kt) for file saving
✅ Custom folder picker using Android Storage Access Framework
✅ Complete documentation.html with step-by-step setup guide
✅ AdMob setup section in documentation — how to swap test IDs for live IDs
✅ key.properties.example template for Android signing
✅ App icon asset (1024×1024 PNG) ready for flutter_launcher_icons
✅ .gitignore pre-configured to exclude keystore and signing files
✅ flutter analyze passes with zero issues

️ Technical Specifications

Framework: Flutter 3.x / Dart 3.x
State Management: Flutter Riverpod 2.6
Audio Engine: ffmpeg_kit_flutter_new_audio 2.5
Ads SDK: google_mobile_ads (latest)
Ad Formats: Banner Ad + Interstitial Ad
Android min SDK: 24 (Android 7.0 Nougat and above)
Android compileSdk: 36
iOS minimum target: iOS 14 and above
Package name: com.smallburnstudios.mp4tomp3 (fully customizable)
Design system: Material You / Material 3

Documentation Covers

Introduction & feature overview
System requirements (Flutter SDK, Android Studio, Xcode, JDK 17)
Folder structure map
How to replace test AdMob IDs with your live Ad Unit IDs
How to register your app in AdMob and get an App ID
How to change the package name / Application ID
How to change the app name (Android + iOS)
How to change the app icon (with flutter_launcher_icons)
How to change the app theme color (single line change)
Android — Generate a release keystore
Android — Create key.properties
Android — Update build.gradle.kts with release signing
Build release APK / AAB
iOS — Change Bundle ID
iOS — Signing & Provisioning Profiles
Troubleshooting common errors
Changelog (starting v1.0)
Support contact

Easy to Customize

Swap AdMob IDs: Two constants in lib/services/ad_service.dart
Change app color: One line in lib/main.dart
Change package name: Two fields in build.gradle.kts + rename Kotlin folder
Change app name: One line in AndroidManifest.xml + one line in Info.plist
Change app icon: Replace assets/icon/icon.png and run one command

Privacy & Security

All conversions happen entirely on the user’s device — no files are ever uploaded
No analytics, no crash reporting, no user tracking beyond what AdMob collects
AdMob follows Google’s own privacy policy and complies with GDPR / CCPA guidelines
Keystore and signing credentials are excluded from Git by default

Changelog

v2.0.0 — August 2026 (AdMob Release)

Added Google AdMob integration — Banner Ad on main screen, Interstitial Ad after each conversion
Added AdService singleton for clean, centralized ad lifecycle management
Interstitial ad pre-caches on app start and auto-reloads after dismissal
Updated documentation with AdMob setup guide (App ID + Ad Unit IDs)

v1.0.0 — August 2026 (Initial Release)

First release of MP4 to MP3 Converter
FFmpeg-powered audio extraction from any MP4 video file
Custom output folder selection using Android Storage Access Framework
Full conversion history screen with file details and quick actions
Share and open converted MP3 files directly from the app
Material 3 design with dark and light theme support
About dialog with app information and feature list
Supports Android 7.0 and above (API level 24+)
Supports iOS 14 and above

Support

We aim to reply within 24 to 48 hours. Use the Comments section on the item page, or email us directly. Please include your purchase code in your message.

© 2026 TechArt Studios · MP4 to MP3 Converter

MP4 to MP3 Converter | Flutter Mobile App