OptionallengthSpeech-rate multiplier (>1 slower, <1 faster).
OptionalnoiseVoice variability (output is stochastic).
OptionalnoiseTiming variability.
OptionalnormalizeScale PCM to peak before output. Default: true.
OptionalspeakerSpeaker index for multi-speaker/style models.
OptionalvolumeGain multiplier applied after normalization. Default: 1.0.
Per-utterance synthesis overrides. Port of
SynthesisConfiginconfig.py.