@picovoice/orca-web

Orca Binding for Web

Orca Text-to-Speech Engine

Made in Vancouver, Canada by Picovoice

Orca is an on-device text-to-speech engine producing high-quality, realistic, spoken audio with zero latency. Orca is:

• Private; All voice processing runs locally.
• Cross-Platform:
  • Linux (x86_64), macOS (x86_64, arm64), and Windows (x86_64)
  • Chrome, Safari, Firefox, and Edge
  • Raspberry Pi (3, 4, 5) and NVIDIA Jetson Nano

Compatibility

• Chrome / Edge
• Firefox
• Safari

Restrictions

IndexedDB is required to use Orca in a worker thread. Browsers without IndexedDB support (i.e. Firefox Incognito Mode) should use Orca in the main thread.

Installation

Package

Using Yarn:

yarn add @picovoice/orca-web

or using npm:

npm install --save @picovoice/orca-web

AccessKey

Orca requires a valid Picovoice AccessKey at initialization. AccessKey acts as your credentials when using Orca SDKs. You can get your AccessKey for free. Make sure to keep your AccessKey secret. Signup or Login to Picovoice Console to get your AccessKey.

Usage

For the web packages, there are two methods to initialize Orca.

Public Directory

NOTE: Due to modern browser limitations of using a file URL, this method does not work if used without hosting a server.

This method fetches the model file from the public directory and feeds it to Orca. Copy a model file for the desired voice (male or female) into the public directory:

cp ${ORCA_MODEL_FILE} ${PATH_TO_PUBLIC_DIRECTORY}

Base64

NOTE: This method works without hosting a server, but increases the size of the model file roughly by 33%.

This method uses a base64 string of the model file and feeds it to Orca. Use the built-in script pvbase64 to base64 your model file:

npx pvbase64 -i ${ORCA_MODEL_FILE} -o ${OUTPUT_DIRECTORY}/${MODEL_NAME}.js

The output will be a js file which you can import into any file of your project. For detailed information about pvbase64, run:

npx pvbase64 -h

Orca Model

Orca saves and caches your model file in IndexedDB to be used by WebAssembly. Use a different customWritePath variable to hold multiple models and set the forceWrite value to true to force re-save a model file.

Either base64 or publicPath must be set to instantiate Orca. If both are set, Orca will use the base64 model.

const orcaModel = {
  publicPath: "${MODEL_RELATIVE_PATH}",
  // or
  base64: "${MODEL_BASE64_STRING}",

  // Optionals
  customWritePath: "orca_model",
  forceWrite: false,
  version: 1,
}

Initialize Orca

Create an instance of Orca on the main thread:

const orca = await Orca.create(
  "${ACCESS_KEY}",
  orcaModel
);

Or create an instance of Orca in a worker thread:

const orca = await OrcaWorker.create(
  "${ACCESS_KEY}",
  orcaModel
);

Custom Pronunciations

Orca allows the embedding of custom pronunciations in the text via the syntax: {word|pronunciation}. The pronunciation is expressed in ARPAbet phonemes, for example:

• "This is a {custom|K AH S T AH M} pronunciation"
• "{read|R IY D} this as {read|R EH D}, please."
• "I {live|L IH V} in {Sevilla|S EH V IY Y AH}. We have great {live|L AY V} sports!"

Synthesize Speech

The synthesize function will send the text to the engine and return the speech audio as an Int16Array.

const speechPcm = await orca.synthesize("${TEXT}");

Speech Control

Orca allows for an additional argument to be provided to the synthesize method to control the synthesized speech:

• speechRate: Controls the speed of the generated speech. Valid values are within [0.7, 1.3]. A higher value produces speech that is faster, and a lower value produces speech that is slower. The default value is 1.0.

const synthesizeParams = {
  speechRate: 1.3
};

const speechPcm = await orca.synthesize("${TEXT}", synthesizeParams);

Orca Properties

To obtain the complete set of valid characters, call .validCharacters. To retrieve the maximum number of characters allowed, call .maxCharacterLimit. The sample rate of Orca is .sampleRate.

Clean Up

Clean up used resources by Orca or OrcaWorker:

await orca.release();

Terminate (Worker only)

Terminate OrcaWorker instance:

await orca.terminate();

Demo

For example usage refer to our Web demo application.