tts

Smallest AI text-to-speech service implementation.

This module provides a WebSocket-based integration with Smallest AI’s Waves API for real-time text-to-speech synthesis.

class pipecat.services.smallest.tts.SmallestTTSModel(*values)[source]

Bases: StrEnum

Available Smallest AI TTS models.

LIGHTNING_V2 = 'lightning-v2'
LIGHTNING_V3_1 = 'lightning-v3.1'
pipecat.services.smallest.tts.language_to_smallest_tts_language(language: Language) → str | None[source]

Convert a Language enum to a Smallest TTS language string.

Parameters:

language – The Language enum value to convert.

Returns:

The Smallest language code string, or None if unsupported.

class pipecat.services.smallest.tts.SmallestTTSSettings(model: str | None | _NotGiven = <factory>, extra: dict[str, ~typing.Any]=<factory>, voice: str | None | _NotGiven = <factory>, language: Language | str | None | _NotGiven = <factory>, speed: float | None | _NotGiven = <factory>, consistency: float | None | _NotGiven = <factory>, similarity: float | None | _NotGiven = <factory>, enhancement: int | None | _NotGiven = <factory>)[source]

Bases: TTSSettings

Settings for SmallestTTSService.

Parameters:

  • speed – Speech speed multiplier.

  • consistency – Consistency level for voice generation (0-1).

  • similarity – Similarity level for voice generation (0-1).

  • enhancement – Enhancement level for voice generation (0-2).

speed: float | None | _NotGiven
consistency: float | None | _NotGiven
similarity: float | None | _NotGiven
enhancement: int | None | _NotGiven
class pipecat.services.smallest.tts.SmallestTTSService(*, api_key: str, base_url: str = 'wss://api.smallest.ai', sample_rate: int | None = None, settings: SmallestTTSSettings | None = None, **kwargs)[source]

Bases: InterruptibleTTSService

Smallest AI real-time text-to-speech service using WebSocket streaming.

Provides real-time text-to-speech synthesis using Smallest AI’s WebSocket API. Supports streaming audio generation with configurable voice parameters and language settings. Handles interruptions by reconnecting the WebSocket.

Example:

tts = SmallestTTSService(
    api_key="your-api-key",
    settings=SmallestTTSService.Settings(
        voice="sophia",
        language=Language.EN,
        speed=1.0,
    ),
)
Settings

alias of SmallestTTSSettings

__init__(*, api_key: str, base_url: str = 'wss://api.smallest.ai', sample_rate: int | None = None, settings: SmallestTTSSettings | None = None, **kwargs)[source]

Initialize the Smallest AI WebSocket TTS service.

Parameters:

  • api_key – Smallest AI API key for authentication.

  • base_url – Base WebSocket URL for the Smallest API.

  • sample_rate – Audio sample rate in Hz. If None, uses default.

  • settings – Runtime-updatable settings for the TTS service.

  • **kwargs – Additional arguments passed to parent InterruptibleTTSService.

can_generate_metrics() → bool[source]

Check if this service can generate processing metrics.

Returns:

True, as Smallest service supports metrics generation.

async flush_audio(context_id: str | None = None)[source]

Flush any pending audio data.

language_to_service_language(language: Language) → str | None[source]

Convert a Language enum to Smallest service language format.

Parameters:

language – The language to convert.

Returns:

The Smallest-specific language code, or None if not supported.

async start(frame: StartFrame)[source]

Start the Smallest TTS service.

Parameters:

frame – The start frame containing initialization parameters.

async stop(frame: EndFrame)[source]

Stop the Smallest TTS service.

Parameters:

frame – The end frame.

async cancel(frame: CancelFrame)[source]

Cancel the Smallest TTS service.

Parameters:

frame – The cancel frame.

async run_tts(text: str, context_id: str) → AsyncGenerator[Frame | None, None][source]

Generate speech from text using Smallest’s WebSocket streaming API.

Parameters:

  • text – The text to synthesize into speech.

  • context_id – Unique identifier for this TTS context.

Yields:

Frame – Audio arrives via WebSocket receive task.