TTS Types

Complete TypeScript type definitions for the TTS API.

Audio Types

GeneratedAudio

Generated audio data from TTS synthesis.

interface GeneratedAudio {
  samples: number[];
  sampleRate: number;
}

samples

number[]

Audio samples as an array of float values in range [-1.0, 1.0].This is raw PCM audio data that can be:

Saved to a WAV file using saveAudioToFile()
Played using an audio library
Processed further for effects or analysis

sampleRate

number

Sample rate of the generated audio in Hz.Common values:

16000 - 16 kHz (voice/telephony)
22050 - 22.05 kHz (common for TTS)
44100 - 44.1 kHz (CD quality)
48000 - 48 kHz (professional audio)

Example:

const audio: GeneratedAudio = await tts.generateSpeech('Hello');
console.log(`Generated ${audio.samples.length} samples`);
console.log(`Sample rate: ${audio.sampleRate}Hz`);
console.log(`Duration: ${audio.samples.length / audio.sampleRate}s`);

GeneratedAudioWithTimestamps

Generated audio with word-level timestamp metadata for subtitles.

interface GeneratedAudioWithTimestamps extends GeneratedAudio {
  subtitles: TtsSubtitleItem[];
  estimated: boolean;
}

subtitles

TtsSubtitleItem[]

Array of subtitle/timestamp entries for each word or token.See TtsSubtitleItem below.

estimated

boolean

Whether timestamps are estimated rather than model-provided.

true - Timestamps are estimated/calculated
false - Timestamps come directly from the TTS model

Example:

const result = await tts.generateSpeechWithTimestamps('Hello world');

console.log('Subtitles:');
result.subtitles.forEach((item) => {
  console.log(`  ${item.text}: ${item.start.toFixed(2)}s - ${item.end.toFixed(2)}s`);
});

if (result.estimated) {
  console.log('Note: Timestamps are estimated');
}

TtsSubtitleItem

Subtitle/timestamp entry for a word or token in synthesized speech.

interface TtsSubtitleItem {
  text: string;
  start: number;
  end: number;
}

text

string

Text token for this time range (word, phoneme, or character).

start

number

Start time in seconds.

end

number

End time in seconds.

Example:

const item: TtsSubtitleItem = {
  text: 'Hello',
  start: 0.0,
  end: 0.5,
};

Model Info Types

TTSModelInfo

Information about TTS model capabilities.

interface TTSModelInfo {
  sampleRate: number;
  numSpeakers: number;
}

sampleRate

number

Sample rate that the model generates audio at (in Hz).

numSpeakers

number

Number of speakers/voices available in the model.

0 or 1 = Single-speaker model
> 1 = Multi-speaker model

Example:

const info = await tts.getModelInfo();

if (info.numSpeakers > 1) {
  console.log(`Multi-speaker model with ${info.numSpeakers} voices`);
  // Can use sid parameter to select different speakers
} else {
  console.log('Single-speaker model');
}

Engine Interfaces

TtsEngine

Batch TTS engine interface returned by createTTS().

interface TtsEngine {
  readonly instanceId: string;
  
  generateSpeech(
    text: string,
    options?: TtsGenerationOptions
  ): Promise<GeneratedAudio>;
  
  generateSpeechWithTimestamps(
    text: string,
    options?: TtsGenerationOptions
  ): Promise<GeneratedAudioWithTimestamps>;
  
  updateParams(options: TtsUpdateOptions): Promise<{
    success: boolean;
    detectedModels: Array<{ type: string; modelDir: string }>;
  }>;
  
  getModelInfo(): Promise<TTSModelInfo>;
  getSampleRate(): Promise<number>;
  getNumSpeakers(): Promise<number>;
  
  destroy(): Promise<void>;
}

See createTTS() documentation for detailed method descriptions.

StreamingTtsEngine

Streaming TTS engine interface returned by createStreamingTTS().

interface StreamingTtsEngine {
  readonly instanceId: string;
  
  generateSpeechStream(
    text: string,
    options: TtsGenerationOptions | undefined,
    handlers: TtsStreamHandlers
  ): Promise<TtsStreamController>;
  
  cancelSpeechStream(): Promise<void>;
  
  startPcmPlayer(sampleRate: number, channels: number): Promise<void>;
  writePcmChunk(samples: number[]): Promise<void>;
  stopPcmPlayer(): Promise<void>;
  
  getModelInfo(): Promise<TTSModelInfo>;
  getSampleRate(): Promise<number>;
  getNumSpeakers(): Promise<number>;
  
  destroy(): Promise<void>;
}

See createStreamingTTS() documentation for detailed method descriptions.

Streaming Types

TtsStreamHandlers

Event handlers for streaming TTS generation.

interface TtsStreamHandlers {
  onChunk?: (chunk: TtsStreamChunk) => void;
  onEnd?: (event: TtsStreamEnd) => void;
  onError?: (event: TtsStreamError) => void;
}

onChunk

(chunk: TtsStreamChunk) => void

Called for each audio chunk as it’s generated.

onEnd

(event: TtsStreamEnd) => void

Called when generation completes or is cancelled.

onError

(event: TtsStreamError) => void

Called when an error occurs during generation.

TtsStreamChunk

Audio chunk received during streaming generation.

interface TtsStreamChunk {
  instanceId?: string;
  requestId?: string;
  samples: number[];
  sampleRate: number;
  progress: number;
  isFinal: boolean;
}

instanceId

string

Instance ID of the TTS engine that generated this chunk.

requestId

string

Request ID for this specific generation (distinguishes concurrent streams).

samples

number[]

Float PCM audio samples in range [-1.0, 1.0].

sampleRate

number

Sample rate of the audio in Hz.

progress

number

Generation progress as a float between 0.0 and 1.0.

isFinal

boolean

true if this is the last chunk in the stream.

TtsStreamEnd

Event emitted when streaming generation ends.

interface TtsStreamEnd {
  instanceId?: string;
  requestId?: string;
  cancelled: boolean;
}

instanceId

string

Instance ID of the TTS engine.

requestId

string

Request ID for this generation.

cancelled

boolean

true if generation was cancelled, false if it completed normally.

TtsStreamError

Event emitted when an error occurs during streaming.

interface TtsStreamError {
  instanceId?: string;
  requestId?: string;
  message: string;
}

instanceId

string

Instance ID of the TTS engine.

requestId

string

Request ID for this generation.

message

string

Error message describing what went wrong.

TtsStreamController

Controller returned by generateSpeechStream() for managing the stream.

interface TtsStreamController {
  cancel(): Promise<void>;
  unsubscribe(): void;
}

cancel

() => Promise<void>

Cancels the ongoing TTS generation.

unsubscribe

() => void

Removes event listeners. Called automatically on end/error, or can be called manually.

Configuration Types

See the Configuration page for detailed documentation of:

TTSInitializeOptions
TtsModelOptions
TtsVitsModelOptions
TtsMatchaModelOptions
TtsKokoroModelOptions
TtsKittenModelOptions
TtsPocketModelOptions
TtsUpdateOptions
TtsGenerationOptions
TTSModelType

Type Imports

Import all TTS types

import type {
  // Engine interfaces
  TtsEngine,
  StreamingTtsEngine,
  
  // Configuration
  TTSInitializeOptions,
  TTSModelType,
  TtsModelOptions,
  TtsVitsModelOptions,
  TtsMatchaModelOptions,
  TtsKokoroModelOptions,
  TtsKittenModelOptions,
  TtsPocketModelOptions,
  TtsUpdateOptions,
  TtsGenerationOptions,
  
  // Audio types
  GeneratedAudio,
  GeneratedAudioWithTimestamps,
  TtsSubtitleItem,
  TTSModelInfo,
  
  // Streaming types
  TtsStreamController,
  TtsStreamHandlers,
  TtsStreamChunk,
  TtsStreamEnd,
  TtsStreamError,
} from 'react-native-sherpa-onnx';

Import runtime constants

import { TTS_MODEL_TYPES } from 'react-native-sherpa-onnx';

console.log('Supported model types:', TTS_MODEL_TYPES);
// ['vits', 'matcha', 'kokoro', 'kitten', 'pocket', 'zipvoice', 'auto']

Core API

Speech-to-Text

Text-to-Speech

Audio Processing

Utilities

Audio Types

GeneratedAudio

GeneratedAudioWithTimestamps

TtsSubtitleItem

Model Info Types

TTSModelInfo

Engine Interfaces

TtsEngine

StreamingTtsEngine

Streaming Types

TtsStreamHandlers

TtsStreamChunk

TtsStreamEnd

TtsStreamError

TtsStreamController

Configuration Types

Type Imports

Import all TTS types

Import runtime constants

See Also

Build docs developers (and LLMs) love

Core API

Speech-to-Text

Text-to-Speech

Audio Processing

Utilities

​Audio Types

​GeneratedAudio

​GeneratedAudioWithTimestamps

​TtsSubtitleItem

​Model Info Types

​TTSModelInfo

​Engine Interfaces

​TtsEngine

​StreamingTtsEngine

​Streaming Types

​TtsStreamHandlers

​TtsStreamChunk

​TtsStreamEnd

​TtsStreamError

​TtsStreamController

​Configuration Types

​Type Imports

​Import all TTS types

​Import runtime constants

​See Also

Build docs developers (and LLMs) love

Audio Types

GeneratedAudio

GeneratedAudioWithTimestamps

TtsSubtitleItem

Model Info Types

TTSModelInfo

Engine Interfaces

TtsEngine

StreamingTtsEngine

Streaming Types

TtsStreamHandlers

TtsStreamChunk

TtsStreamEnd

TtsStreamError

TtsStreamController

Configuration Types

Type Imports

Import all TTS types

Import runtime constants

See Also