Kokoro TTS Flutter

https://github.com/yansigit/kokoro-tts-flutter
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Kokoro TTS Flutter is a multi-language text-to-speech (TTS) library for Flutter, powered by ONNX...
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### Flutter TTS with int8 Quantized ONNX Model

Source: https://github.com/yansigit/kokoro-tts-flutter/blob/main/README.md

This Dart example shows how to configure and use an `int8`-quantized ONNX model with Kokoro TTS Flutter. By setting the `isInt8` flag to `true` in `KokoroConfig`, the library utilizes the optimized model for improved performance and reduced memory usage. Remember to place the `int8` model file in the assets folder.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

void main() async {
  // Example configuration for an int8 model
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0-int8.onnx', // Path to your int8 model
    voicesPath: 'assets/voices.json',
    isInt8: true, // Enable int8 model support
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  // ... rest of your code
}
```

--------------------------------

### Trim Audio Silence using AudioUtils

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Removes leading and trailing silence from generated audio using RMS-based detection. The utility provides configurable silence thresholds and frame parameters. Accepts Float32List audio data and returns the trimmed audio along with start and end indices. Requires the 'kokoro_tts_flutter' package.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';
import 'dart:typed_data';

void processAudio() {
  // Sample audio data (simulated)
  final audio = Float32List.fromList([
    0.0, 0.0, 0.01, 0.5, 0.7, 0.6, 0.4, 0.01, 0.0, 0.0
  ]);

  // Trim silence from audio
  final (trimmedAudio, indices) = AudioUtils.trimSilence(
    audio,
    topDb: 60.0,        // Silence threshold in dB
    frameLength: 2048,  // Analysis frame length
    hopLength: 512,     // Hop length between frames
  );

  print('Original length: ${audio.length}');
  print('Trimmed length: ${trimmedAudio.length}');
  print('Trim indices: start=${indices[0]}, end=${indices[1]}');
}
```

--------------------------------

### Initialize Tokenizer for Phonemization

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Sets up the tokenizer for converting text into phonemes using the malsami G2P engine. It loads vocabulary mappings and lexicon data to enable text-to-phoneme conversion.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

Future<void> useTokenizer() async {
  // Create tokenizer with optional custom lexicon
  final tokenizer = Tokenizer(
    config: TokenizerConfig(lexiconPath: 'assets/lexicon.json'),
  );

  // Initialize the tokenizer
  await tokenizer.ensureInitialized();

  // Convert text to phonemes
  final phonemes = await tokenizer.phonemize(
    'Hello world!',
    lang: 'en-us',
  );
  print('Phonemes: $phonemes');

  // Tokenize phonemes to IDs
  final tokens = tokenizer.tokenize(phonemes);
  print('Token IDs: $tokens');
}
```

--------------------------------

### Basic Text-to-Speech Synthesis in Flutter

Source: https://github.com/yansigit/kokoro-tts-flutter/blob/main/README.md

This Dart code demonstrates the basic usage of the Kokoro TTS Flutter library. It initializes the TTS engine with model and voice paths, phonemizes input text, and then generates audio samples for the specified voice. Ensure model and voice files are correctly placed in the assets folder and declared in pubspec.yaml.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

void main() async {
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0.onnx',
    voicesPath: 'assets/voices.json',
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  final tokenizer = Tokenizer();
  await tokenizer.ensureInitialized();
  final phonemes = await tokenizer.phonemize('Hello world!', lang: 'en-us');

  final ttsResult = await kokoro.createTTS(
    text: phonemes,
    voice: 'af_heart',
    isPhonemes: true,
  );
  // ttsResult.audio contains the generated audio samples
}
```

--------------------------------

### Initialize Kokoro TTS Engine

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Configures and initializes the Kokoro TTS engine, loading the ONNX model, voice style vectors, and tokenizer resources. The engine must be initialized before speech generation.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

void main() async {
  // Configure the TTS engine with model and voice files
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0.onnx',
    voicesPath: 'assets/voices.json',
  );

  // Create and initialize the engine
  final kokoro = Kokoro(config);
  await kokoro.initialize();

  // Engine is now ready to generate speech
  print('Kokoro TTS initialized successfully');

  // Get available voices
  final voices = kokoro.getVoices();
  print('Available voices: $voices');
}
```

--------------------------------

### Use Int8 Quantized Models for Performance

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Enables the use of int8 quantized ONNX models for improved inference performance and reduced memory footprint. This configuration maintains audio quality while speeding up generation.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

Future<void> useQuantizedModel() async {
  // Configure with int8 quantized model
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0-int8.onnx',
    voicesPath: 'assets/voices.json',
    isInt8: true,  // Enable int8 model support
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  // Generate speech using quantized model
  final ttsResult = await kokoro.createTTS(
    text: 'Quantized models are faster and use less memory.',
    voice: 'af_heart',
    speed: 1.0,
    lang: 'en-us',
  );

  print('Generated audio duration: ${ttsResult.duration}s');
}
```

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### Convert Binary Voices to JSON using Python

Source: https://github.com/yansigit/kokoro-tts-flutter/blob/main/README.md

This Python script converts binary voice data files (e.g., voices-v1.0.bin) into JSON format, improving compatibility with Flutter applications. It loads the binary file using NumPy and exports all voices or specific ones like 'af_heart' into readable JSON files.

```python
import numpy as np
import json

data = np.load("voices-v1.0.bin")

# Export all voices to voices.json
all_voices = {k: v.tolist() for k, v in data.items()}
with open("voices.json", "w") as f:
    json.dump(all_voices, f)

# Optionally, export just af_heart
if "af_heart" in data:
    af_heart = data["af_heart"].tolist()
    with open("af_heart.json", "w") as f:
        json.dump(af_heart, f)
```

--------------------------------

### Work with Voice Objects in Kokoro TTS Flutter

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Allows querying available voices and accessing voice metadata, including language, gender, and style vectors. Voice objects provide detailed control over voice selection and style. Requires the 'kokoro_tts_flutter' package and voice metadata files.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

Future<void> exploreVoices() async {
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0.onnx',
    voicesPath: 'assets/voices.json',
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  // Get all available voice IDs
  final voiceIds = kokoro.getVoices();
  print('Available voices: $voiceIds');

  // Get detailed voice information
  final voice = kokoro.getVoice('af_heart');
  if (voice != null) {
    print('Voice ID: ${voice.id}');
    print('Voice name: ${voice.name}');
    print('Language: ${voice.languageCode}');
    print('Gender: ${voice.gender}');
    print('Style vectors: ${voice.styleVectors.length}');
  }

  // Use voice object directly
  final ttsResult = await kokoro.createTTS(
    text: 'Using voice object directly',
    voice: voice,  // Pass Voice object instead of String ID
    speed: 1.0,
    lang: 'en-us',
  );
}
```

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### Concatenate Audio Buffers using AudioUtils

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Combines multiple audio buffers into a single continuous audio stream. This utility handles both Float32List and Int8List formats automatically. Accepts a list of audio buffers and returns a single concatenated buffer. Requires the 'kokoro_tts_flutter' package.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';
import 'dart:typed_data';

void combineAudio() {
  // Multiple audio buffers
  final buffer1 = Float32List.fromList([0.1, 0.2, 0.3]);
  final buffer2 = Float32List.fromList([0.4, 0.5, 0.6]);
  final buffer3 = Float32List.fromList([0.7, 0.8, 0.9]);

  // Concatenate all buffers
  final combined = AudioUtils.concatenateAudio([
    buffer1,
    buffer2,
    buffer3,
  ]);

  print('Combined length: ${combined.length}');
  print('Combined audio: $combined');
}
```

--------------------------------

### Generate Speech Directly from Phonemes using Dart

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Generates speech directly from pre-computed phonemes, bypassing text-to-phoneme conversion for custom pronunciation. Requires the Kokoro TTS Flutter library and a Tokenizer.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

Future<void> usePhonemes() async {
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0.onnx',
    voicesPath: 'assets/voices.json',
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  // First, convert text to phonemes
  final tokenizer = Tokenizer();
  await tokenizer.ensureInitialized();
  final phonemes = await tokenizer.phonemize(
    'Hello world!',
    lang: 'en-us',
  );

  // Generate speech directly from phonemes
  final ttsResult = await kokoro.createTTS(
    text: phonemes,
    voice: 'af_heart',
    speed: 1.0,
    lang: 'en-us',
    isPhonemes: true,  // Indicate input is already phonemes
  );

  print('Generated from phonemes: ${ttsResult.duration}s');
}
```

--------------------------------

### Calculate Audio RMS using AudioUtils

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Computes Root Mean Square values for audio frames, useful for volume analysis and silence detection. RMS calculation divides audio into frames and computes energy levels. Accepts Float32List audio data and parameters for frame length and hop length. Requires the 'kokoro_tts_flutter' package.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';
import 'dart:typed_data';

void analyzeAudio() {
  // Sample audio data
  final audio = Float32List.fromList([
    0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
    0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.0
  ]);

  // Calculate RMS values for frames
  final rmsValues = AudioUtils.rms(
    audio,
    frameLength: 4,  // 4 samples per frame
    hopLength: 2,    // 2 samples between frames
  );

  print('RMS values: $rmsValues');
  print('Number of frames: ${rmsValues.length}');
}
```

--------------------------------

### Stream Audio Generation with Kokoro TTS Flutter

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Generates speech in streaming mode for long texts, yielding audio chunks as they are generated. This enables progressive playback and reduced memory usage for lengthy content. Requires the 'kokoro_tts_flutter' package and pre-trained model/voice files.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

Future<void> streamSpeech() async {
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0.onnx',
    voicesPath: 'assets/voices.json',
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  // Stream audio generation for long text
  final stream = kokoro.createTTSStream(
    text: 'This is a very long text that will be generated in chunks. '
          'Each chunk will be yielded as it becomes available.',
    voice: 'af_heart',
    speed: 1.0,
    lang: 'en-us',
    trim: true,
  );

  // Process each audio chunk as it arrives
  await for (final chunk in stream) {
    print('Received chunk: ${chunk.duration}s, ${chunk.audio.length} samples');
    // Play or process audio chunk here
  }
}
```

--------------------------------

### Generate Speech from Text

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Converts text into speech audio with customizable voice, speed, and language settings. This function handles phonemization automatically and returns audio samples along with metadata.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

Future<void> generateSpeech() async {
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0.onnx',
    voicesPath: 'assets/voices.json',
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  // Generate speech from text
  final ttsResult = await kokoro.createTTS(
    text: 'Hello world! This is a test.',
    voice: 'af_heart',
    speed: 1.0,
    lang: 'en-us',
    isPhonemes: false,
    trim: true,
  );

  // Access generated audio data
  print('Audio duration: ${ttsResult.duration} seconds');
  print('Sample rate: ${ttsResult.sampleRate} Hz');
  print('Audio samples: ${ttsResult.audio.length}');
  print('Phonemes used: ${ttsResult.phonemes}');

  // Convert to PCM format for playback
  final pcmData = ttsResult.toPcm();
  final int16Data = ttsResult.toInt16PCM();
}
```

--------------------------------

### Dispose TTS Engine using Dart

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Releases resources utilized by the TTS engine, including the ONNX model runner. It is crucial to dispose of the engine when finished to free memory and prevent resource leaks. Requires the Kokoro TTS Flutter library.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

Future<void> lifecycle() async {
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0.onnx',
    voicesPath: 'assets/voices.json',
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  try {
    // Use the TTS engine
    final ttsResult = await kokoro.createTTS(
      text: 'Goodbye!',
      voice: 'af_heart',
      lang: 'en-us',
    );

    print('Generated speech: ${ttsResult.duration}s');
  } finally {
    // Always dispose when done
    await kokoro.dispose();
    print('TTS engine disposed');
  }
}
```

--------------------------------

### Adjust Speech Speed using Dart

Source: https://context7.com/yansigit/kokoro-tts-flutter/llms.txt

Controls the speaking rate of generated speech by adjusting the speed parameter. Supported speeds range from 0.5 to 2.0, affecting playback rate without altering pitch. Requires the Kokoro TTS Flutter library.

```dart
import 'package:kokoro_tts_flutter/kokoro_tts_flutter.dart';

Future<void> adjustSpeed() async {
  const config = KokoroConfig(
    modelPath: 'assets/kokoro-v1.0.onnx',
    voicesPath: 'assets/voices.json',
  );

  final kokoro = Kokoro(config);
  await kokoro.initialize();

  // Generate at different speeds
  final normalSpeed = await kokoro.createTTS(
    text: 'Normal speed speech.',
    voice: 'af_heart',
    speed: 1.0,  // Normal speed
    lang: 'en-us',
  );

  final slowSpeed = await kokoro.createTTS(
    text: 'Slow speed speech.',
    voice: 'af_heart',
    speed: 0.75,  // 75% speed
    lang: 'en-us',
  );

  final fastSpeed = await kokoro.createTTS(
    text: 'Fast speed speech.',
    voice: 'af_heart',
    speed: 1.5,  // 150% speed
    lang: 'en-us',
  );

  print('Normal: ${normalSpeed.duration}s');
  print('Slow: ${slowSpeed.duration}s');
  print('Fast: ${fastSpeed.duration}s');
}
```
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