Function extractAudio

apps/web/workflows/transcribe.ts:179–261

(
	videoId: string,
	userId: string,
	video: typeof videos.$inferSelect,
)

}

async function extractAudio(
	videoId: string,
	userId: string,
	video: typeof videos.$inferSelect,
): Promise<string | null> {
	"use step";

	const [bucket] = await Storage.getAccessForVideo(
		decodeStorageVideo(video),
	).pipe(runPromise);

	const videoUrl = await resolveVideoSourceUrl(videoId, userId, video);

	const useMediaServer = isMediaServerConfigured();
	console.log(
		`[transcribe] Audio detection: useMediaServer=${useMediaServer}, videoId=${videoId}`,
	);

	let hasAudio: boolean;
	let audioBuffer: Buffer;

	if (useMediaServer) {
		try {
			const probe = await probeVideoViaMediaServer(videoUrl);
			console.log(
				`[transcribe] Probe result for ${videoId}: audioCodec=${probe.audioCodec}, videoCodec=${probe.videoCodec}, duration=${probe.duration}, audioChannels=${probe.audioChannels}, sampleRate=${probe.sampleRate}`,
			);
			hasAudio = probe.audioCodec !== null;
		} catch (probeError) {
			console.error(
				`[transcribe] Probe failed for ${videoId}, falling back to audio check:`,
				probeError,
			);
			hasAudio = await checkHasAudioTrackViaMediaServer(videoUrl);
			console.log(
				`[transcribe] Fallback audio check result for ${videoId}: hasAudio=${hasAudio}`,
			);
		}

		if (!hasAudio) {
			console.log(
				`[transcribe] No audio track detected for ${videoId} via media server`,
			);
			return null;
		}

		audioBuffer = await extractAudioViaMediaServer(videoUrl);
	} else {
		hasAudio = await checkHasAudioTrack(videoUrl);
		console.log(
			`[transcribe] Local ffmpeg audio check for ${videoId}: hasAudio=${hasAudio}`,
		);
		if (!hasAudio) {
			return null;
		}

		const result = await extractAudioFromUrl(videoUrl);