diff --git a/include/ddstream.idl b/include/ddstream.idl
index 644401559ac..947e2bcde4f 100644
--- a/include/ddstream.idl
+++ b/include/ddstream.idl
@@ -44,14 +44,14 @@ pointer_default(unique)
 interface IDirectDrawMediaStream : IMediaStream
 {
 	HRESULT GetFormat(
-		[out, optional] DDSURFACEDESC *pDDSDCurrent,
-		[out, optional] IDirectDrawPalette **ppDirectDrawPalette,
-		[out, optional] DDSURFACEDESC *pDDSDDesired,
-		[out, optional] DWORD *pdwFlags);
+		[out] DDSURFACEDESC *pDDSDCurrent,
+		[out] IDirectDrawPalette **ppDirectDrawPalette,
+		[out] DDSURFACEDESC *pDDSDDesired,
+		[out] DWORD *pdwFlags);
 
 	HRESULT SetFormat(
 		[in] const DDSURFACEDESC *pDDSurfaceDesc,
-		[in, optional] IDirectDrawPalette *pDirectDrawPalette);
+		[in] IDirectDrawPalette *pDirectDrawPalette);
 
 	HRESULT GetDirectDraw(
 		[out] IDirectDraw **ppDirectDraw);
@@ -60,8 +60,8 @@ interface IDirectDrawMediaStream : IMediaStream
 		[in] IDirectDraw *pDirectDraw);
 
 	HRESULT CreateSample(
-		[in, optional] IDirectDrawSurface *pSurface,
-		[in, optional] const RECT *pRect,
+		[in] IDirectDrawSurface *pSurface,
+		[in] const RECT *pRect,
 		[in] DWORD dwFlags,
 		[out] IDirectDrawStreamSample **ppSample);
 
@@ -79,8 +79,8 @@ pointer_default(unique)
 interface IDirectDrawStreamSample : IStreamSample
 {
 	HRESULT GetSurface(
-		[out, optional] IDirectDrawSurface ** ppDirectDrawSurface,
-		[out, optional] RECT * pRect);
+		[out] IDirectDrawSurface ** ppDirectDrawSurface,
+		[out] RECT * pRect);
 
 	HRESULT SetRect(
 		[in] const RECT * pRect);