RTCRtpScriptTransform: RTCRtpScriptTransform() constructor

Syntax

new RTCRtpScriptTransform(worker)
new RTCRtpScriptTransform(worker, options)
new RTCRtpScriptTransform(worker, options, transfer)

Parameters

worker

A Worker, which will define code for one or more WebRTC transform streams.

options Optional

An arbitrary object that will be made available in the worker. This is most commonly used to inform the worker whether it injected into the WebRTC sender or receiver pipeline, and hence which transform should be applied. However it may also be used to send any other object, such as a MessagePort for communicating dynamically with the transformer.

transfer Optional

An optional array of transferable objects that will be transferred to the worker. After transfer, these objects are unusable in the main thread.

Exceptions

DataCloneError DOMException

Thrown if an object in transfer cannot be transferred.

Examples

The first example below shows construction of a RTCRtpScriptTransform that is then assigned to a RTCRtpSender.transform. The constructor takes an optional object with the property name and senderTransform. The worker can use this option to understand when it is transforming encoded frames from the encoder (rather than incoming frames from the packetizer).

// Create a worker containing a TransformStream
const worker = new Worker("worker.js");
videoSender.transform = new RTCRtpScriptTransform(worker, {
  name: "senderTransform",
});

Any property name and value can be used in the options, as long as they can be serialized (and transferred if specified in the last constructor parameter). The code below transfers the second port of a MessageChannel to the worker, which we might do in order to dynamically update transform code with (say) a new encryption key.

// Create a worker containing a TransformStream
const worker = new Worker("worker.js");
const channel = new MessageChannel();

const transform = new RTCRtpScriptTransform(
  worker,
  { purpose: "encrypt", port: channel.port2 },
  [channel.port2],
);

Specifications

Browser compatibility

See also

• Using WebRTC Encoded Transforms
• RTCRtpSender.transform
• RTCRtpReceiver.transform