diff --git a/packages/transcode/ffmpeg.ts b/packages/transcode/ffmpeg.ts
index 542741a4..d52b0c9d 100644
--- a/packages/transcode/ffmpeg.ts
+++ b/packages/transcode/ffmpeg.ts
@@ -30,7 +30,7 @@ export function ffmpeg(input: URL | ReadableStream<Uint8Array>, flags: FFmpegFla
   // Spawn the FFmpeg process
   const command = new Deno.Command('ffmpeg', {
     args,
-    stdin: input instanceof ReadableStream ? 'piped' : undefined,
+    stdin: input instanceof ReadableStream ? 'piped' : 'null',
     stdout: 'piped',
   });