Reference - Web SDK

Symbl Class

The Symbl class takes in an optional SymblConfig. If no config is passed, you must authenticate later using the init method.

init(symblConfig: SymblConfig)

Validates and initializes Symbl with application configuration.

Example

const symbl = new Symbl();
symbl.init({
  accessToken: '<Your Access Token>',
  // appId: '<Your App ID>',
  // appSecret: '<Your App Secret>',
})

createConnection(sessionId?: string, audioStream?: AudioStream)

Accepts an optional sessionId and an optional instance of AudioStream.

Validates that sessionId is unique and then opens a Symbl Streaming API WebSocket connection.

Returns an instance of StreamingAPIConnection.

Example

const symbl = new Symbl();
const connection = symbl.createConnection("abc123");

createAndStartNewConnection(options: StreamingAPIConnectionConfig, audioStream?: AudioStream)

Accepts a required Connection Config object and an optional instance of AudioStream.

Opens a new connection and starts processing audio.

Returns an instance of StreamingAPIConnection.

Example

const symbl = new Symbl();
const connection = symbl.createAndStartNewConnection({
  config: {
    encoding: "OPUS"
  }
});

subscribeToConnection(sessionId: string)

Accepts a required Session ID to subscribe to.

Establishes a Subscribe API connection with session ID.

Returns an instance of SubscribeAPIConnection

Example

const symbl = new Symbl();
const connection = symbl.subscribeToConnection(sessionId);

Symbl.wait(time: number, unit: string = TimeUnit.MS)

Waits for provided amount of time in the supplied units (ms, s, min).

Example

// Waits 5 seconds
await Symbl.wait(5000);

StreamingAPIConnection Class

The StreamingAPIConnection class represents a Streaming API WebSocket connection. In most instances you would be interfacing with this class from the return variable on createConnection or createAndStartNewConnection. You can also import it from the Web SDK and use it separately: import { StreamingAPIConnection } from '@symblai/symbl-web-sdk';. StreamingAPIConnection inherits from the BaseConnection base class.

connect()

Opens a Symbl Streaming API WebSocket connection. If already connected it logs a warning. Once connected, it sends out the connected event.

Example

let connection = new StreamingAPIConnection();
connection.connect();

disconnect()

Disconnects from Symbl Streaming API WebSocket.

Example

connection.disconnect();

startProcessing(options: StreamingAPIConnectionConfig)

Accepts a required Connection Config.

Triggers the streaming connection to begin processing audio through Symbl websocket.

Example

connection.startProcessing({
  config: {
    encoding: "OPUS"
  }
});

stopProcessing()

Triggers the streaming connection to stop processing audio through Symbl websocket. If disconnectOnStopRequest is set to false, the WebSocket enters a non-processing state which can be resumed later by calling startProcessing again. If disconnectOnStopRequest is not set or set to true the WebSocket connection must be re-opened to start processing audio again.

Example

connection.stopProcessing()

on(eventName: EventTypes, callback: Function)

Subscribe to an event and perform a callback when it's fired.

Checkout out our Events and Callbacks reference for more information.

Example

connection.on('connected', () => {
  console.log('I am connected!');
})

modifySampleRate(sampleRateHertz: number)

Accepts a sample rate in hertz, such as 48000.

Updates the sample rate mid-stream and sends out the session_modified event.

Example

connection.modifySampleRate(48000);

getSessionId()

Getter for the sessionId.

Example

const sessionId = connection.getSessionId();

isProcessing()

Returns true if the connection is processing audio.

Example

connection.isProcessing();

isConnected()

Returns true if connected to the WebSocket.

Example

connection.isConnected();

updateAudioStream(audioStream: AudioStream)

Accepts an AudioStream instance.

Replaces the existing audio stream with the one provided. Stops processing if currently processing audio.

Example

const audioStream = new OpusAudioStream();
connection.updateAudioStream(audioStream);

SubscribeAPIConnection Class

The SubscribeAPIConnection class represents a Subscribe API WebSocket connection. In most instances you would be interfacing with this class from the return variable on subscribeToConnection. You can also import it from the Web SDK and use it separately: import { SubscribeAPIConnection } from '@symblai/symbl-web-sdk';. SubscribeAPIConnection inherits from the BaseConnection base class.

connect()

Opens a Symbl Subscribe API WebSocket connection. If already connected it logs a warning. Once connected, it sends out the connected event.

Example

let connection = new StreamingAPIConnection(id, audioStream);
connection.connect();

disconnect()

Disconnects from the Symbl Subscribe API WebSocket.

Example

connection.disconnect();

on(eventName: EventTypes, callback: Function)

Subscribe to an event and perform a callback when it's fired.

Example

connection.on('connected', () => {
  console.log('I am connected!');
})

isConnected()

Returns true if connected to the WebSocket.

Example

connection.isConnected();

AudioStream Class

LINEAR16AudioStream and OpusAudioStream both inherit from the AudioStream base class, so their usage is identical. The main difference is LINEAR16AudioStream is meant to be paired with the LINEAR16 encoding type, and the OpusAudioStream is meant to be paired with the OPUS encoding type.

attachAudioDevice(deviceId: string, mediaStream: MediaStream)

Accepts an optional deviceId and an optional MediaStream. If no deviceId is passed, the default device is used.

Attaches audio device either through default browser method creating a MediaStream or via a passed in MediaStream

Example

audioStream.attachAudioDevice("my-device-id");

detachAudioDevice()

Disconnects processor to cleanly detach the audio input device.

Example

audioStream.detachAudioDevice();

updateAudioDevice(deviceId: string, mediaStream: MediaStream)

Accepts an optional deviceId and an optional MediaStream. If no deviceId is passed, the default device is used.

Updates the audio device in use by the audio stream.

Example

audioStream.updateAudioDevice("my-device-id");

🚧

Make sure to use the appropriate DOM element type for SourceElement functions. Source elements include HTMLVideoElement and HTMLAudioElement.

attachAudioSourceElement(audioSourceDomElement)

Accepts a required HTMLAudioElement or HTMLSourceElement. A type with the Content-Type is required and the src attribute is also required. The src attribute can be a URL or a Blob

Attaches an audio element to the processor and starts processing audio data from the audio file. In order to start processing you need to call .play() on the audio element. We recommend doing this after the processing_started Event has been fired.

Example

// Authenticate with Symbl
const symbl = new Symbl({
  accessToken: "< MY ACCESS TOKEN >"
});

// Create your audio element
const myAudioElement = new Audio();
myAudioElement.type = "audio/mp3";
myAudioElement.src = "link-to-file.mp3";

// Attach audio element to AudioStream
const audioStream = new LINEAR16AudioStream();
audioStream.attachAudioSourceElement(myAudioElement);

// Create connection and start processing audio
const connection = symbl.createConnection("abc123", audioStream);
connection.startProcessing({
  config: {
    encoding: "LINEAR16"
  }
});

// Play the element once audio is ready to be processed.
connection.on("processing_started", () => {
  myAudioElement.play();
});

detachAudioSourceElement()

Disconnects processor to cleanly detach the audio source element.

Example

audioStream.detachAudioSourceElement();

updateAudioSourceElement(audioSourceDomElement)

Accepts a required HTMLAudioElement or HTMLSourceElement. A type with the Content-Type is required and the src attribute is also required. The src attribute can be a URL or a Blob

Updates the audio element attached to the audio stream.

Example

audioStream.updateAudioSourceElement(myAudioElement);

attachVideoSourceElement(videoSourceDomElement)

Accepts a required HTMLVideoElement or HTMLSourceElement. A type with the Content-Type is required and the src attribute is also required. The src attribute can be a URL or a Blob

Attaches a video element to the processor and starts processing audio data from the video file. To start processing you need to call .play() on the video element. Symbl recommends doing this after the processing_started event has been fired.

Example

// Authenticate with Symbl
const symbl = new Symbl({
  accessToken: "< MY ACCESS TOKEN >"
});

// Create your audio element
const myVideoElement = document.createElement("video");
myVideoElement.type = "video/mp4";
myVideoElement.src = "link-to-file.mp4";

// Attach audio element to AudioStream
const audioStream = new LINEAR16AudioStream();
audioStream.attachVideoSourceElement(myVideoElement);

// Create connection and start processing audio
const connection = symbl.createConnection("abc123", audioStream);
connection.startProcessing({
  config: {
    encoding: "LINEAR16"
  }
});

// Play the element once audio is ready to be processed.
connection.on("processing_started", () => {
  myAudioElement.play();
});

detachVideoSourceElement()

Disconnects the processor to cleanly detach the video source element.

Example

audioStream.detachVideoSourceElement();

updateVideoSourceElement(videoSourceDomElement)

Accepts a required HTMLVideoElement or HTMLSourceElement. A type with the Content-Type is required and the src attribute is also required. The src attribute can be a URL or a Blob

Updates the video element attached to the audio stream.

Example

audioStream.updateVideoSourceElement(myVideoElement);

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