VoiceStudio/docs/generation-parameters.md

Generation Parameters

Parameters can be passed as keyword arguments to model.generate(...) or via the OmniVoiceGenerationConfig dataclass. See below for the full list and which category each belongs to.

# 1) Direct keyword arguments
audio = model.generate(text="Hello world", num_step=32, guidance_scale=2.0)

# 2) Via OmniVoiceGenerationConfig dataclass
from omnivoice import OmniVoiceGenerationConfig

config = OmniVoiceGenerationConfig(num_step=32, guidance_scale=2.0)
audio = model.generate(text="Hello world", generation_config=config)

Decoding

Parameter	Type	Default	Description
num_step	int	32	Number of iterative unmasking steps. Higher values improve quality but slow down generation. Use 16 for faster inference.
denoise	bool	True	Prepend the `<
guidance_scale	float	2.0	Classifier-free guidance scale.
t_shift	float	0.1	Time-step shift for the noise schedule. Smaller values emphasise earlier steps in decoding.

Sampling

Parameter	Type	Default	Description
position_temperature	float	5.0	Temperature for mask-position selection. 0 = greedy (deterministic). Higher values increase randomness.
class_temperature	float	0.0	Temperature for token sampling at each step. 0 = greedy (deterministic). Higher values increase randomness.
layer_penalty_factor	float	5.0	Penalty applied to deeper codebook layers, encouraging earlier (lower) layers to unmask first.

Duration & Speed

These accept a single value applied to all items, or a per-item list (useful in batch mode):

# Fixed 10-second output
audio = model.generate(text="Hello, this is a test of duration control", duration=10.0)

# Faster speech (1.2x faster than estimated)
audio = model.generate(text="Hello, this is a test of duration control", speed=1.2)

Parameter	Type	Default	Description
duration	float or list[float | None]	None	Fixed output duration in seconds. Overrides speed when set.
speed	float or list[float | None]	None	Speed factor. Values > 1.0 produce shorter audio (faster); values < 1.0 produce longer audio (slower). Ignored when duration is set. Defaults to 1.0 when both are None.

Priority: duration > speed.

Pre/Post Processing

Parameter	Type	Default	Description
preprocess_prompt	bool	True	Whether to apply preprocessing to the voice-clone prompt audio (remove long silences in reference audio, add punctuation in the end of reference text).
postprocess_output	bool	True	Apply post-processing to generated audio (remove long silences).

Tip — reference-clip quality transfers. Zero-shot cloning mirrors the acoustics of the reference clip, not just the voice: a clip recorded in an echoey room clones echoey. Record dry and close-mic for clean output. No effect preset adds reverb unless you choose one that declares it (Cinematic, Warm).

Long-Form Generation

To support stable long-form speech generation with low VRAM consumption, the text is automatically split into smaller segments when the estimated duration of the generated speech exceeds audio_chunk_duration, with each segment producing approximately audio_chunk_duration seconds of audio. This approach allows the model to accept arbitrarily long text and generate arbitrarily long speech with near-constant VRAM consumption.

Parameter	Type	Default	Description
audio_chunk_duration	float	15.0	Target chunk duration (seconds) when splitting long text.
audio_chunk_threshold	float	30.0	Estimated audio duration (seconds) above which chunking is activated.