diff --git a/dlls/amstream/amstream.c b/dlls/amstream/amstream.c
index d17b456fa67..0001f1fcbb8 100644
--- a/dlls/amstream/amstream.c
+++ b/dlls/amstream/amstream.c
@@ -110,7 +110,7 @@ static ULONG WINAPI IAMMultiMediaStreamImpl_Release(IAMMultiMediaStream* iface)
 }
 
 /*** IMultiMediaStream methods ***/
-static HRESULT WINAPI IAMMultiMediaStreamImpl_GetInformation(IAMMultiMediaStream* iface, char* pdwFlags, STREAM_TYPE* pStreamType)
+static HRESULT WINAPI IAMMultiMediaStreamImpl_GetInformation(IAMMultiMediaStream* iface, DWORD* pdwFlags, STREAM_TYPE* pStreamType)
 {
     IAMMultiMediaStreamImpl *This = (IAMMultiMediaStreamImpl *)iface;
 
diff --git a/include/mmstream.idl b/include/mmstream.idl
index c488959335b..19d34214ac8 100644
--- a/include/mmstream.idl
+++ b/include/mmstream.idl
@@ -90,7 +90,7 @@ pointer_default(unique)
 interface IMultiMediaStream : IUnknown {
 
 	HRESULT GetInformation(
-		[out, optional] char *pdwFlags,
+		[out, optional] DWORD *pdwFlags,
 		[out, optional] STREAM_TYPE *pStreamType);
 
 	HRESULT GetMediaStream(