dart_piper_tts 0.1.0

TTS in Dart using Piper TTS models + audio player in one package.

flutter_piper_tts

TTS in Dart (or Flutter) using Piper TTS models + audio player in one package.

All onnx models are run via https://crates.io/crates/ort.

Built-in phonemizer is done via neural g2p ipa phonemizer model obtained from https://huggingface.co/OpenVoiceOS/g2p-mbyt5-12l-ipa-childes-espeak-onnx. This is done to avoid dealing with espeak GPL3 license and keep this package's MIT license. You can also provide your own ipa phonemes via speakFromPhonemes to bypass phonemes generation.

Piper TTS models can be downloaded from https://huggingface.co/rhasspy/piper-voices/tree/main.

Audio playback is done using https://crates.io/crates/tinyaudio.

Usage

Disclaimer: examples below are using the Flutter package

• Download Piper TTS model of your choice, make sure to also prepare the *.onnx.json file
• Make them available to the device file system, eg. copying from your asset bundle to device application support directory

  final directory = await getApplicationSupportDirectory();
  final modelPath = join(directory.path, 'en_US-hfc_female-medium.onnx');
  final configPath = join(directory.path, 'en_US-hfc_female-medium.onnx.json');

  final exists = await File(modelPath).exists();

  if (!exists) {
    final modelData = await rootBundle.load(
      'assets/en_US-hfc_female-medium.onnx',
    );
    List<int> bytes = modelData.buffer.asUint8List(
      modelData.offsetInBytes,
      modelData.lengthInBytes,
    );

    await File(modelPath).writeAsBytes(bytes, flush: true);

    final configData = await rootBundle.load(
      'assets/en_US-hfc_female-medium.onnx.json',
    );
    bytes = configData.buffer.asUint8List(
      configData.offsetInBytes,
      configData.lengthInBytes,
    );
    await File(configPath).writeAsBytes(bytes, flush: true);
  }

• Initialize the package

  await PiperTTS.init();
  final tts = await PiperTTS.create(modelPath, configPath);

• Call speak

  await tts.speak("Hello world");
  tts.pause();
  tts.resume();
  await tts.speak("Bye", waitForCompletion: false)
  tts.stop();

Supported platforms

• Android
• iOS
• MacOS
• Windows and Linux (not tested)

TODO

• Better support for subsentence separator like comma
• Adjust speed (with change in pitch/not)