files/en-us/web/api/rtcencodedaudioframe/data/index.md
{{APIRef("WebRTC")}}{{AvailableInWorkers("window_and_dedicated")}}
The data property of the {{domxref("RTCEncodedAudioFrame")}} interface returns a buffer containing the data for an encoded frame.
An {{jsxref("ArrayBuffer")}}.
This example WebRTC encoded transform shows how you might get the frame data in a {{domxref("TransformStream")}} transform() function modify the bits.
The transform() function constructs a {{jsxref("DataView")}} on the buffer in the frame data property, and also creates a view on a new {{jsxref("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.
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}}
{{Compat}}