BaseTTSProvider

Defined in: src/providers/base/BaseTTSProvider.ts:68

Abstract base class shared by every TTS provider in CompositeVoice.

Remarks

BaseTTSProvider sits between BaseProvider and the two transport- specific bases (LiveTTSProvider and RestTTSProvider). It adds the audio callback and metadata callback mechanisms that all TTS providers use to deliver synthesized audio back to the SDK core.

The audio delivery pattern mirrors the STT transcription callback:

1. The SDK (or consumer) registers listeners via onAudio and optionally onMetadata.
2. Subclasses call emitAudio for each chunk of synthesized audio and emitMetadata once at the beginning of synthesis (if the provider can report format details up front).

Inheritance hierarchy:

BaseProvider
 +-- BaseTTSProvider          <-- you are here
      +-- LiveTTSProvider     (WebSocket streaming TTS)
      +-- RestTTSProvider     (REST batch TTS)

You typically do not extend BaseTTSProvider directly. Instead, extend LiveTTSProvider for WebSocket/streaming providers or RestTTSProvider for batch/REST providers.

Example

import { BaseTTSProvider } from 'composite-voice';
import type { TTSProviderConfig } from 'composite-voice';
import type { AudioChunk } from 'composite-voice';

class CustomTTSProvider extends BaseTTSProvider {
  constructor(config: TTSProviderConfig) {
    super('rest', config);
  }

  protected async onInitialize(): Promise<void> { }
  protected async onDispose(): Promise<void> { }

  async synthesize(text: string): Promise<Blob> {
    const audioBlob = await myEngine.speak(text);
    return audioBlob;
  }
}

See

• LiveTTSProvider for WebSocket-based streaming TTS
• RestTTSProvider for REST/batch TTS
• BaseProvider for the root provider lifecycle

Extends

• BaseProviderClass

Constructors

Constructor

new BaseTTSProvider(
   type, 
   config, 
   logger?): BaseTTSProvider;

Defined in: src/providers/base/BaseTTSProvider.ts:94

Create a new TTS provider.

Parameters

Returns

BaseTTSProvider

Overrides

BaseProviderClass.constructor

Properties

Methods

assertReady()

protected assertReady(): void;

Defined in: src/providers/base/BaseProvider.ts:255

Guard that throws if the provider has not been initialized.

Returns

void

Remarks

Call at the start of any method that requires the provider to be ready.

Throws

Error Thrown with a descriptive message when initialized is false.

Inherited from

BaseProviderClass.assertReady

dispose()

dispose(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:154

Clean up resources and dispose of the provider.

Returns

Promise<void>

Remarks

Delegates to the subclass hook onDispose and resets the initialized flag. If the provider is not initialized, the call is a no-op.

Throws

Re-throws any error raised by onDispose.

Inherited from

BaseProviderClass.dispose

emitAudio()

protected emitAudio(chunk): void;

Defined in: src/providers/base/BaseTTSProvider.ts:138

Emit a synthesized audio chunk to the registered callback.

Parameters

Returns

void

Remarks

Subclasses call this method for each chunk of audio produced during synthesis. If no callback has been registered the chunk is silently dropped.

emitMetadata()

protected emitMetadata(metadata): void;

Defined in: src/providers/base/BaseTTSProvider.ts:154

Emit audio metadata to the registered callback.

Parameters

Returns

void

Remarks

Typically called once at the start of synthesis when the provider knows the output format. If no callback has been registered the metadata is silently dropped.

getConfig()

getConfig(): TTSProviderConfig;

Defined in: src/providers/base/BaseTTSProvider.ts:165

Get a shallow copy of the current TTS configuration.

Returns

TTSProviderConfig

A new TTSProviderConfig object.

Overrides

BaseProviderClass.getConfig

initialize()

initialize(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:127

Initialize the provider, making it ready for use.

Returns

Promise<void>

Remarks

Calls the subclass hook onInitialize. If the provider has already been initialized the call is a no-op.

Throws

ProviderInitializationError Thrown when onInitialize rejects. The original error is wrapped with the provider class name for diagnostics.

Inherited from

BaseProviderClass.initialize

isReady()

isReady(): boolean;

Defined in: src/providers/base/BaseProvider.ts:178

Check whether the provider has been initialized and is ready.

Returns

boolean

true when initialize has completed successfully and dispose has not yet been called.

Inherited from

BaseProviderClass.isReady

onAudio()

onAudio(callback): void;

Defined in: src/providers/base/BaseTTSProvider.ts:109

Register a callback to receive synthesized audio chunks.

Parameters

Returns

void

Remarks

All TTS providers — regardless of transport — deliver audio through this callback. CompositeVoice registers it during pipeline setup so that audio data flows into the AudioPlayer.

onConfigUpdate()

protected onConfigUpdate(_config): void;

Defined in: src/providers/base/BaseProvider.ts:242

Hook called after updateConfig merges new values.

Parameters

Returns

void

Remarks

The default implementation is a no-op. Override in subclasses to react to runtime configuration changes (e.g. reconnect with a new API key).

Inherited from

BaseProviderClass.onConfigUpdate

onDispose()

abstract protected onDispose(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:229

Provider-specific disposal logic.

Returns

Promise<void>

Remarks

Subclasses must implement this method to release any resources acquired during onInitialize (e.g. close connections, free memory).

Inherited from

BaseProviderClass.onDispose

onInitialize()

abstract protected onInitialize(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:217

Provider-specific initialization logic.

Returns

Promise<void>

Remarks

Subclasses must implement this method to perform any setup required before the provider can be used (e.g. validate credentials, open connections, load models).

Inherited from

BaseProviderClass.onInitialize

onMetadata()

onMetadata(callback): void;

Defined in: src/providers/base/BaseTTSProvider.ts:124

Register a callback to receive audio metadata.

Parameters

Returns

void

Remarks

Metadata (sample rate, encoding, channels, etc.) helps the AudioPlayer configure playback correctly. Providers may emit metadata once at the start of synthesis but are not required to.

updateConfig()

updateConfig(config): void;

Defined in: src/providers/base/BaseProvider.ts:201

Merge partial configuration updates into the current config.

Parameters

Returns

void

Remarks

After merging, the subclass hook onConfigUpdate is called so providers can react to changed values at runtime.

Inherited from

BaseProviderClass.updateConfig