Supertonic TTS Flutter #

High-quality multilingual text-to-speech (TTS) engine for Flutter applications. Powered by ONNX Runtime for fast, local neural speech synthesis.

Note: This is an unofficial Flutter port of the Supertonic project.

Features #

• 🌍 Multilingual Support - English, Korean, Spanish, Portuguese, and French
• 🎭 Multiple Voice Styles - 10 unique voices (5 male, 5 female) with different characteristics
• ⚡ Local Processing - All inference happens on-device, no server calls required
• 🎛️ Customizable - Adjustable speech speed and quality settings
• 📱 Cross-Platform - Supports Android, iOS, and macOS
• 🔊 High Quality - Neural TTS powered by advanced diffusion models

Platform Support #

Installation #

Add this to your package's pubspec.yaml file:

dependencies:
  supertonic_flutter: ^0.1.1

Setup #

1. Add Assets #

Add the ONNX model files and voice styles to your app's assets directory:

Note: Model files are not included in the package due to their size. Download them from Hugging Face and add them to your app.

assets/
├── onnx/
│   ├── duration_predictor.onnx
│   ├── text_encoder.onnx
│   ├── vector_estimator.onnx
│   ├── vocoder.onnx
│   ├── tts.json
│   └── unicode_indexer.json
└── voice_styles/
    ├── M1.json, M2.json, M3.json, M4.json, M5.json
    └── F1.json, F2.json, F3.json, F4.json, F5.json

2. Update pubspec.yaml #

flutter:
  assets:
    - assets/onnx/
    - assets/voice_styles/

3. Platform Configuration #

This package uses flutter_onnxruntime which requires specific platform configurations:

➡️ Android

Add ProGuard rules to prevent ONNX Runtime classes from being obfuscated.

Create or edit android/app/proguard-rules.pro:

-keep class ai.onnxruntime.** { *; }

Or run this command from your terminal:

echo "-keep class ai.onnxruntime.** { *; }" > android/app/proguard-rules.pro

For more information, refer to the flutter_onnxruntime troubleshooting guide.

➡️ iOS

ONNX Runtime requires minimum version iOS 16 and static linkage.

In ios/Podfile, update the following lines:

platform :ios, '16.0'

# ... existing code ...

target 'Runner' do
  use_frameworks! :linkage => :static

  # ... existing code ...
end

And add to the post_install hook:

post_install do |installer|
  installer.pods_project.targets.each do |target|
    flutter_additional_ios_build_settings(target)
    target.build_configurations.each do |config|
      config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '16.0'
    end
  end
end

➡️ macOS

macOS build requires minimum version macOS 14.

In macos/Podfile, change:

platform :osx, '14.0'

Update the "Minimum Deployments" to 14.0 in Xcode:

open macos/Runner.xcworkspace

Then in Xcode:

1. Select Runner project in the navigator
2. Select Runner target
3. Go to General tab
4. Change Minimum Deployments to 14.0

Also add to the post_install hook in your Podfile:

post_install do |installer|
  installer.pods_project.targets.each do |target|
    flutter_additional_macos_build_settings(target)
    target.build_configurations.each do |config|
      config.build_settings['MACOSX_DEPLOYMENT_TARGET'] = '14.0'
      config.build_settings['ALLOW_STATIC_FRAMEWORK_TRANSITIVE_DEPENDENCIES'] = 'YES'
    end
  end
end

Demo #

Check out the example/ directory for a full-featured demo app with language selection, voice switching, and customizable settings.

Usage #

Basic Example #

import 'package:supertonic_flutter/supertonic_flutter.dart';

// Initialize the TTS engine
final tts = SupertonicTTS();
await tts.initialize();

// Synthesize speech
final result = await tts.synthesize(
  'Hello, world!',
  language: 'en',
  voiceStyle: 'M1',
);

// Convert to WAV and save
final wavBytes = result.toWavBytes();
final file = File('output.wav');
await file.writeAsBytes(wavBytes);

With Audio Player #

import 'package:supertonic_flutter/supertonic_flutter.dart';

final tts = SupertonicTTS();
final player = TTSAudioPlayer();

// Initialize
await tts.initialize();

// Synthesize and play
final result = await tts.synthesize(
  'Hello, this is a test.',
  language: 'en',
  voiceStyle: 'F1',
  config: TTSConfig(
    speechSpeed: 1.05,
    denoisingSteps: 5,
  ),
);

await player.play(result);