diff --git a/types/fluent-ffmpeg/index.d.ts b/types/fluent-ffmpeg/index.d.ts
index 317a772d59..db8f54b325 100644
--- a/types/fluent-ffmpeg/index.d.ts
+++ b/types/fluent-ffmpeg/index.d.ts
@@ -292,7 +292,7 @@ declare namespace Ffmpeg {
         saveToFile(output: string): FfmpegCommand;
         save(output: string): FfmpegCommand;
         writeToStream(stream: stream.Writable, options?: { end?: boolean }): stream.Writable;
-        pipe(stream: stream.Writable, options?: { end?: boolean }): stream.Writable;
+        pipe(stream?: stream.Writable, options?: { end?: boolean }): stream.Writable|stream.PassThrough;
         stream(stream: stream.Writable, options?: { end?: boolean }): stream.Writable;
         takeScreenshots(config: number | ScreenshotsConfig, folder?: string): FfmpegCommand;
         thumbnail(config: number | ScreenshotsConfig, folder?: string): FfmpegCommand;