The MediaStreamTrackProcessor
interface of the Insertable Streams for MediaStreamTrack API
consumes a MediaStreamTrack
object's source and generates a stream of media frames.
The following example is from the article Insertable streams for MediaStreamTrack, and demonstrates a barcode scanner application, which transforms the stream accessed via MediaStreamTrackProcessor.readable
by highlighting the barcode.
const stream = await getUserMedia({ video: true });
const videoTrack = stream.getVideoTracks()[0];
const trackProcessor = new MediaStreamTrackProcessor({ track: videoTrack });
const trackGenerator = new MediaStreamTrackGenerator({ kind: "video" });
const transformer = new TransformStream({
async transform(videoFrame, controller) {
const barcodes = await detectBarcodes(videoFrame);
const newFrame = highlightBarcodes(videoFrame, barcodes);
videoFrame.close();
controller.enqueue(newFrame);
},
});
trackProcessor.readable
.pipeThrough(transformer)
.pipeTo(trackGenerator.writable);