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.

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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.

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• 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.