RTCEncodedAudioFrame: data property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Note: This feature is available in Dedicated Web Workers.

The data property of the RTCEncodedAudioFrame interface returns a buffer containing the data for an encoded frame.

Value

An ArrayBuffer.

Examples

This example WebRTC encoded transform shows how you might get the frame data in a TransformStream transform() function modify the bits.

The transform() function constructs a DataView on the buffer in the frame data property, and also creates a view on a new ArrayBuffer. It then writes the negated bytes in the original data to the new buffer, assigns the buffer to the encoded frame data property, and enqueues the modified frame on the stream.

js
addEventListener("rtctransform", (event) => {
  const transform = new TransformStream({
    async transform(encodedFrame, controller) {
      // Reconstruct the original frame.
      const view = new DataView(encodedFrame.data);

      // Construct a new buffer
      const newData = new ArrayBuffer(encodedFrame.data.byteLength);
      const newView = new DataView(newData);

      // Negate all bits in the incoming frame
      for (let i = 0; i < encodedFrame.data.byteLength; ++i) {
        newView.setInt8(i, ~view.getInt8(i));
      }

      encodedFrame.data = newData;
      controller.enqueue(encodedFrame);
    },
  });
  event.transformer.readable
    .pipeThrough(transform)
    .pipeTo(event.transformer.writable);
});

Note that the surrounding code shown here is described in Using WebRTC Encoded Transforms.

Specifications

Specification
WebRTC Encoded Transform
# dom-rtcencodedaudioframe-data

Browser compatibility

BCD tables only load in the browser

See also