RTCRtpScriptTransformer: writable property

Value

A WritableStream.

Examples

The following example shows how RTCRtpScriptTransformer.readable is piped through a TransformStream to RTCRtpScriptTransformer.writable.

addEventListener("rtctransform", (event) => {
  let transform;
  // Select a transform based on passed options
  if (event.transformer.options.name === "senderTransform")
    transform = createSenderTransform(); // A TransformStream
  else if (event.transformer.options.name === "receiverTransform")
    transform = createReceiverTransform(); // A TransformStream
  else return;

  // Pipe frames from the readable to writeable through TransformStream
  event.transformer.readable
    .pipeThrough(transform)
    .pipeTo(event.transformer.writable);
});

The code implements a handler for the rtctransform event, which is fired at the global worker object on construction of the corresponding RTCRtpScriptTransform, and when new frames are enqueued for processing. event.transformer is the RTCRtpScriptTransformer that has the writable and readable properties.

A different TransformStream is created to process outgoing and incoming frames, using createSenderTransform() or createReceiverTransform(), respectively (implementations not shown). The event handler chooses the correct transform stream to use based on options passed through from the RTCRtpScriptTransform constructor and assigns it to transform.

The code calls ReadableStream.pipeThrough() on the readable to pipe encoded frames through the selected TransformStream, and then ReadableStream.pipeTo() to pipe them to the RTCRtpScriptTransformer.writable.

Specifications

Browser compatibility