TTS Transformers

TTS Transformers in OpenVoiceOS (OVOS) are plugins that process synthesized speech audio after the Text-to-Speech (TTS) engine generates it but before it's played back to the user.

They enable post-processing of audio to apply effects, enhance clarity, voice clone or tailor the output to specific needs.

How They Work

The typical flow for speech output in OVOS is:

  1. Dialog Generation: The assistant formulates a textual response.
  2. Dialog Transformation: Optional plugins modify the text to adjust tone or style.
  3. Text-to-Speech (TTS): The text is converted into speech audio.
  4. TTS Transformation: Plugins apply audio effects or modifications to the speech.
  5. Playback: The final audio is played back to the user.

TTS Transformers operate in step 4, allowing for dynamic audio enhancements without altering the original TTS output.

Configuration

To enable TTS Transformers, add them to your mycroft.conf under the tts_transformers section:

"tts_transformers": {
  "plugin_name": {
    // plugin-specific configuration
  }
}

Replace "plugin_name" with the identifier of the desired plugin and provide any necessary configuration parameters.

Available TTS Transformer Plugins

OVOS SoX TTS Transformer

  • Purpose: Applies various audio effects using SoX (Sound eXchange) to the TTS output.

  • Features:

    • Pitch shifting
    • Reverb
    • Tempo adjustment
    • Equalization
    • Noise reduction
    • And many more

  • Installation:

  pip install ovos-tts-transformer-sox-plugin
  • Configuration Example:
  "tts_transformers": {
    "ovos-tts-transformer-sox-plugin": {
      "effects": ["pitch 300", "reverb"]
    }
  }
  • Requirements: Ensure SoX is installed and available in your system's PATH.
  • Source: GitHub Repository

Creating Custom TTS Transformers

To develop your own TTS Transformer:

Create a Python Class:

from ovos_plugin_manager.templates.transformers import TTSTransformer

class MyCustomTTSTransformer(TTSTransformer):
   def __init__(self, config=None):
       super().__init__("my-custom-tts-transformer", priority=10, config=config)

   def transform(self, wav_file: str, context: dict = None) -> Tuple[str, dict]:
       """Transform passed wav_file and return path to transformed file"""
       # Apply custom audio processing to wav_file
       return modified_wav_file, context

Register as a Plugin: In your setup.py, include:

entry_points={
   'ovos.plugin.tts_transformer': [
       'my-custom-tts-transformer = my_module:MyCustomTTSTransformer'
   ]
}

Install and Configure: After installation, add your transformer to the mycroft.conf:

"tts_transformers": {
 "my-custom-tts-transformer": {}
}

By leveraging TTS Transformers, you can enhance the auditory experience of your OVOS assistant, tailoring speech output to better suit your preferences or application requirements.([ovoshatchery.github.io][4])