Function startRecording

apps/chrome-extension/src/offscreen/recorder.ts:819–1163

(request: StartRecordingRequest)

};

const startRecording = async (request: StartRecordingRequest) => {
	if (activeRecording || startInProgress || retryInProgress) {
		// Thrown before this attempt owns anything, so the cleanup below must
		// never run for it: a duplicate start would otherwise tear down — and
		// delete server-side — the live recording it was rejected to protect.
		throw new Error("Recording is already active");
	}
	startInProgress = true;
	startCancelRequested = false;

	// Everything acquired by THIS attempt. The failure path releases exactly
	// these; module state like activeRecording is only touched when this
	// attempt is the one that set it.
	const ownedStreams: MediaStream[] = [];
	let ownedVideoId: string | null = null;
	let ownedSpool: RecordingSpool | null = null;
	let ownedRecording: ActiveRecording | null = null;

	try {
		status = { phase: "creating" };

		const mainStream = await getMainStream(request);
		ownedStreams.push(mainStream);
		throwIfStartCanceled();
		const captureSource = getCaptureSource(request, mainStream);
		if (captureSource) {
			broadcastCaptureSource(captureSource);
		}
		const microphoneStream = await getMicrophoneStream(
			request.settings.microphone,
			request.mode,
		);
		if (microphoneStream) {
			ownedStreams.push(microphoneStream);
		}
		throwIfStartCanceled();
		const { width, height, fps } = getStreamSize(mainStream);
		const videoTracks = mainStream.getVideoTracks();
		if (videoTracks.length === 0) {
			throw new Error("No video track was captured");
		}
		const recordingStream = new MediaStream(videoTracks);
		const streams = microphoneStream
			? [mainStream, microphoneStream]
			: [mainStream];
		const audioContext = addAudioTracks({
			output: recordingStream,
			streams,
			routeFirstStreamToSpeakers: request.mode === "tab",
		});
		const hasAudio = recordingStream.getAudioTracks().length > 0;
		const pipeline = selectRecordingPipeline(hasAudio);
		if (!pipeline) throw new Error("No supported recorder format is available");

		const { videoCodec, audioCodec } = describeRecordingCodecs(
			pipeline.mimeType,
			hasAudio,
		);