fix: mp4 audio mux codecId miss

plugin/webtransport/web/example.js

@@ -0,0 +1,109 @@
+async function getDisplayMedia() {
+  return navigator.mediaDevices.getDisplayMedia({
+    video: {
+      frameRate: {
+        ideal: 30,
+      },
+    },
+    audio: {
+      numberOfChannels: 2,
+      sampleRate: 44100,
+    },
+  });
+}
+
+let stream;
+
+let recordingChunks = [];
+
+const myWorker = new Worker("./worker.js");
+
+async function startRecording() {
+  myWorker.onmessage = (chunk) => {
+    recordingChunks.push(chunk.data);
+  };
+
+  myWorker.postMessage({ type: "START" });
+
+  stream = await getDisplayMedia();
+
+  const videoTrack = stream.getVideoTracks()[0];
+  const audioTrack = stream.getAudioTracks()[0];
+
+  if (videoTrack) {
+    const videoTrackProcessor = new MediaStreamTrackProcessor({
+      track: videoTrack,
+    });
+
+    videoTrackProcessor.readable.pipeTo(
+      new WritableStream({
+        write: (chunk) => {
+          myWorker.postMessage(
+            {
+              type: "DATA_VIDEO",
+              chunk,
+            },
+            [chunk]
+          );
+        },
+      })
+    );
+  }
+
+  if (audioTrack) {
+    const audioTrackProcessor = new MediaStreamTrackProcessor({
+      track: audioTrack,
+    });
+
+    audioTrackProcessor.readable.pipeTo(
+      new WritableStream({
+        write: (chunk) => {
+          myWorker.postMessage(
+            {
+              type: "DATA_AUDIO",
+              chunk,
+            },
+            [chunk]
+          );
+        },
+      })
+    );
+  }
+}
+
+function pauseRecording() {
+  myWorker.postMessage({ type: "PAUSE" });
+}
+
+function resumeRecording() {
+  myWorker.postMessage({ type: "RESUME" });
+}
+
+async function stopRecording() {
+  try {
+    myWorker.postMessage({ type: "STOP" });
+
+    stream.getTracks().forEach((track) => {
+      track.stop();
+    });
+
+    // Save the file
+    const fileHandle = await window.showSaveFilePicker({
+      suggestedName: "recording.flv",
+      types: [
+        {
+          description: "FLV Video",
+          accept: { "video/x-flv": [".flv"] },
+        },
+      ],
+    });
+
+    const writableFileStream = await fileHandle.createWritable();
+    await writableFileStream.write(new Blob(recordingChunks));
+    await writableFileStream.close();
+
+    recordingChunks = [];
+  } catch (error) {
+    console.error("Error stopping recording:", error);
+  }
+}