diff --git a/dlls/amstream/amstream.c b/dlls/amstream/amstream.c
index 81584d6e8c3..f8ae2a6e39b 100644
--- a/dlls/amstream/amstream.c
+++ b/dlls/amstream/amstream.c
@@ -35,7 +35,7 @@
 WINE_DEFAULT_DEBUG_CHANNEL(amstream);
 
 typedef struct {
-    IAMMultiMediaStream lpVtbl;
+    const IAMMultiMediaStreamVtbl *lpVtbl;
     LONG ref;
     IGraphBuilder* pFilterGraph;
     IPin* ipin;
@@ -63,7 +63,7 @@ HRESULT AM_create(IUnknown *pUnkOuter, LPVOID *ppObj)
         return E_OUTOFMEMORY;
     }
 
-    object->lpVtbl.lpVtbl = &AM_Vtbl;
+    object->lpVtbl = &AM_Vtbl;
     object->ref = 1;
 
     *ppObj = object;
diff --git a/dlls/amstream/mediastream.c b/dlls/amstream/mediastream.c
index 697b03bdff1..dc4ec642cf9 100644
--- a/dlls/amstream/mediastream.c
+++ b/dlls/amstream/mediastream.c
@@ -36,7 +36,7 @@
 WINE_DEFAULT_DEBUG_CHANNEL(amstream);
 
 typedef struct {
-    IMediaStream lpVtbl;
+    const IMediaStreamVtbl *lpVtbl;
     LONG ref;
     IMultiMediaStream* Parent;
     MSPID PurposeId;
@@ -44,7 +44,7 @@ typedef struct {
 } IMediaStreamImpl;
 
 typedef struct {
-    IDirectDrawMediaStream lpVtbl;
+    const IDirectDrawMediaStreamVtbl *lpVtbl;
     LONG ref;
     IMultiMediaStream* Parent;
     MSPID PurposeId;
@@ -67,7 +67,7 @@ HRESULT MediaStream_create(IMultiMediaStream* Parent, const MSPID* pPurposeId, S
         return E_OUTOFMEMORY;
     }
 
-    object->lpVtbl.lpVtbl = &MediaStream_Vtbl;
+    object->lpVtbl = &MediaStream_Vtbl;
     object->ref = 1;
 
     object->Parent = Parent;
@@ -207,7 +207,7 @@ HRESULT DirectDrawMediaStream_create(IMultiMediaStream* Parent, const MSPID* pPu
         return E_OUTOFMEMORY;
     }
 
-    object->lpVtbl.lpVtbl = &DirectDrawMediaStream_Vtbl;
+    object->lpVtbl = &DirectDrawMediaStream_Vtbl;
     object->ref = 1;
 
     object->Parent = Parent;
diff --git a/dlls/amstream/mediastreamfilter.c b/dlls/amstream/mediastreamfilter.c
index af335fdeafe..4a4d7123e16 100644
--- a/dlls/amstream/mediastreamfilter.c
+++ b/dlls/amstream/mediastreamfilter.c
@@ -36,7 +36,7 @@
 WINE_DEFAULT_DEBUG_CHANNEL(amstream);
 
 typedef struct {
-    IMediaStreamFilter lpVtbl;
+    const IMediaStreamFilterVtbl *lpVtbl;
     LONG ref;
     CRITICAL_SECTION csFilter;
     FILTER_STATE state;
@@ -63,7 +63,7 @@ HRESULT MediaStreamFilter_create(IUnknown *pUnkOuter, LPVOID *ppObj)
         return E_OUTOFMEMORY;
     }
 
-    object->lpVtbl.lpVtbl = &MediaStreamFilter_Vtbl;
+    object->lpVtbl = &MediaStreamFilter_Vtbl;
     object->ref = 1;
 
     *ppObj = object;
@@ -120,7 +120,7 @@ static ULONG WINAPI MediaStreamFilterImpl_Release(IMediaStreamFilter * iface)
 
     if (!refCount)
     {
-        This->lpVtbl.lpVtbl = NULL;
+        This->lpVtbl = NULL;
         HeapFree(GetProcessHeap(), 0, This);
     }