v0.4.51

RealtimeTTS v0.4.51 Release Notes

• added on_word callback to TextToAudioStream that gets called when a word gets played out
  Supported by AzureEngine and english voices of KokoroEngine.
  An instance of class TimingInfo from BaseEngine.py gets submitted as parameter. It carries the members word, start_time and end_time. For examples please look into tests/kokoro_test.py and tests/azure_test.py

WordTimings.mp4

v0.4.50

RealtimeTTS v0.4.50 Release Notes

• added possibility to mix voices for KokoroEngine:

  engine.set_voice("0.714*af_nicole + 0.286*af_sky")

This feature allows you to mix a custom voice. You can use 🛠️ this tool and copy/paste the voice combination formula.

📝 Code to test voice mixing mixing voices with Kokoro

v0.4.49

RealtimeTTS v0.4.49 Release Notes

• added speed parameter for KokoroEngine
  KokoroEngine takes a default_speed parameter and it can be set with engine.set_speed(speed: float).
• #271

v0.4.48

RealtimeTTS v0.4.48 Release Notes

• set_voice method of CoquiEngine now also accepts a list of wav file references as parameter

v0.4.47

RealtimeTTS v0.4.47 Release Notes

• bugfix: paused streams could not be stopped

v0.4.46

RealtimeTTS v0.4.46 Release Notes

• support for more kokoro voices (japanese, chinese) by installing with pip install "RealtimeTTS[kokoro,jp,zh]"

v0.4.43

RealtimeTTS v0.4.43 Release Notes

• raises kokoro library dependency to version 0.7.3 from 2025-04-02 and therefore hopefully fixes #259

v0.4.42

RealtimeTTS v0.4.42 Release Notes

• KokoroEngine can now be installed with pip install RealtimeTTS[kokoro] (does not need external installation anymore)
• supports Kokoro-V1.0
• support for more voices

v0.4.41

RealtimeTTS v0.4.41 Release Notes

New Feature: KokoroEngine Support

• KokoroEngine Integration

  • Introduces support for the Kokoro 82M TTS engine.
  • Provides access to a variety of Kokoro voice models.

• Installation:

  pip install realtimetts[all]==0.4.41

• Setup Resources:

  • Kokoro installation guide: Kokoro Installation
  • Test script: kokoro_test.py
  • Engine implementation: kokoro_engine.py

Usage Overview

from RealtimeTTS import TextToAudioStream, KokoroEngine

# Initialize Kokoro engine
engine = KokoroEngine(kokoro_root="path/to/Kokoro-82M")

# Switch voice as needed
engine.set_voice("af_sky")

# Create audio stream
stream = TextToAudioStream(engine)

# Feed and play audio using Kokoro voices
stream.feed("Hello world")
stream.play()

v0.4.40

RealtimeTTS v0.4.4 Release Notes

Configurable Playback Parameters

New Parameters: frames_per_buffer and playout_chunk_size

• Purpose:

  • These new parameters provide finer control over audio playback buffering, which is especially useful for mitigating stuttering issues on Unix-based systems.

• Details:

  1. frames_per_buffer:

     • Controls the number of audio frames processed per buffer by PyAudio.
     • Lower values reduce latency but increase CPU usage, while higher values reduce CPU load but increase latency.
     • Recommended Settings for Stuttering:
       • Start by setting frames_per_buffer to 256.
       • If issues persist, reduce it further to 128.

     Example:

     stream = TextToAudioStream(engine, frames_per_buffer=256)

  2. playout_chunk_size:

     • Specifies the size (in bytes) of audio chunks played out to the stream.
     • Works in conjunction with frames_per_buffer to optimize audio smoothness.
     • Defaults to dynamic calculation, but can be explicitly set for precise control.

     Example:

     stream = TextToAudioStream(engine, playout_chunk_size=1024)

How These Parameters Address Stuttering:

• On Unix systems, default buffer sizes may cause sporadic stuttering during audio playback due to timing mismatches between the audio stream and system audio drivers.
• By reducing frames_per_buffer to 256 or 128, the playback becomes more responsive and better aligned with system timing.
• Adjusting playout_chunk_size further enhances playback smoothness by ensuring optimal chunk delivery to the audio stream.

---

Usage Examples

Basic Configuration:

from RealtimeTTS import TextToAudioStream, PiperEngine

engine = PiperEngine(piper_path="path/to/piper.exe", voice=my_voice)
stream = TextToAudioStream(
    engine=engine,
    frames_per_buffer=256,  # Start with 256 to reduce stuttering
    playout_chunk_size=1024 # Optional for further customization
)
stream.play()

Fine-Tuning for Stuttering:

• If playback issues occur:
  1. Set frames_per_buffer to 256 (recommended starting point).
  2. Reduce to 128 if stuttering persists.
  3. Optionally adjust playout_chunk_size to a fixed value like 1024 or 512.

---

• Backward Compatibility:
  • Defaults for frames_per_buffer and playout_chunk_size maintain compatibility with previous versions, requiring no changes for existing setups unless adjustments are needed.