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Usage guide

Setup, environment variables, and Python/JavaScript/Go usage examples.

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OpenAITTS

OpenAI Text-to-Speech provider plugin. Wraps the OpenAI TTS API to synthesize speech from text, supporting both streaming and non-streaming output. The default model (gpt-4o-mini-tts) offers prompt-driven voice control: accent, emotion, intonation, and speed can all be shaped via a plain-English voice instruction in addition to the speed multiplier.

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Constructor

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api_key
str | None
OpenAI API key. Falls back to the OPENAI_API_KEY environment variable when None.
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voice
str
default:"ash"
Built-in voice name to use for synthesis. Defaults to "ash". Available voices: alloy, ash, ballad, cedar, coral, echo, fable, marin, nova, onyx, sage, shimmer, verse marin and cedar are recommended for the highest quality. Older models (tts-1, tts-1-hd) support only alloy, ash, coral, echo, fable, onyx, nova, sage, and shimmer.
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model
OpenAITTSModel | str
default:"gpt-4o-mini-tts"
TTS model identifier. Defaults to "gpt-4o-mini-tts". Options: "gpt-4o-mini-tts": newest, most capable; supports prompt-driven voice control (emotion, accent, intonation). "tts-1": lower latency, reduced quality. "tts-1-hd": higher quality, increased latency.
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sample_rate
int
default:"24000"
Output audio sample rate in Hz. Defaults to 24000.
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speed
Optional[float]
Speaking speed multiplier. None uses the provider default (1.0). Range is 0.25 – 4.0.
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stream
bool
default:"True"
When True (default), audio is returned as a streaming response; False requests the full audio before playback.

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aclose

Release any resources held by the provider.

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emit

Emit an event, invoking all registered handlers with the given arguments. Handlers are called in registration order. Coroutine handlers are scheduled on the running event loop. If the emitter is closed, the call is a no-op.
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event
T
required
The event to emit.

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interrupt

Interrupt and cancel the current synthesis for the active session, if any.

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off

Remove a previously registered handler for an event. If the handler is not registered for the event, the call is a no-op.
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event
T
required
The event the handler was registered for.
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callback
Callable[..., Any]
required
The handler to remove.

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on

Register a handler for an event. Can be used directly by passing a callback, or as a decorator when callback is omitted.
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event
T
required
The event to listen for.
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callback
Callable[..., Any] | None
The handler to invoke when the event is emitted. If None, a decorator is returned that registers the decorated function.
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returns
Callable[..., Any]
The registered callback when callback is provided, otherwise a decorator that registers and returns the function it wraps.

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on_first_audio_byte

Register the callback invoked when the first audio byte is produced.
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callback
'Callable[[int, int], Awaitable[None] | None]'
required
A callable, optionally async, invoked with synthesis timing information when the first audio byte is emitted.

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synthesize

Synthesize the given text into speech. Implementations should convert the text to audio. The default behavior forwards the text to the active session for playback when one is present.
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text
Any
required
The text to synthesize; coerced to a string if needed.

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OpenAITTSModel