diff --git a/dlls/strmbase/pin.c b/dlls/strmbase/pin.c
index 0c1b7cc623f..48f24973d69 100644
--- a/dlls/strmbase/pin.c
+++ b/dlls/strmbase/pin.c
@@ -1210,7 +1210,7 @@ HRESULT BaseInputPin_Construct(const IPinVtbl *InputPin_Vtbl, LONG inputpin_size
 
     if (SUCCEEDED(InputPin_Init(InputPin_Vtbl, pPinInfo, vtbl, pCritSec, allocator, pPinImpl)))
     {
-        *ppPin = (IPin *)pPinImpl;
+        *ppPin = &pPinImpl->pin.IPin_iface;
         return S_OK;
     }
 
diff --git a/dlls/strmbase/pospass.c b/dlls/strmbase/pospass.c
index 42900c685af..45eb23482de 100644
--- a/dlls/strmbase/pospass.c
+++ b/dlls/strmbase/pospass.c
@@ -152,9 +152,9 @@ static HRESULT SeekOuter_QueryInterface(PassThruImpl *This, REFIID riid, LPVOID
         {
             HRESULT hr;
 
-            IUnknown_AddRef((IUnknown *)&(This->IUnknown_inner));
-            hr = IUnknown_QueryInterface((IUnknown *)&(This->IUnknown_inner), riid, ppv);
-            IUnknown_Release((IUnknown *)&(This->IUnknown_inner));
+            IUnknown_AddRef(&This->IUnknown_inner);
+            hr = IUnknown_QueryInterface(&This->IUnknown_inner, riid, ppv);
+            IUnknown_Release(&This->IUnknown_inner);
             This->bAggregatable = TRUE;
             return hr;
         }
@@ -163,21 +163,21 @@ static HRESULT SeekOuter_QueryInterface(PassThruImpl *This, REFIID riid, LPVOID
         return E_NOINTERFACE;
     }
 
-    return IUnknown_QueryInterface((IUnknown *)&(This->IUnknown_inner), riid, ppv);
+    return IUnknown_QueryInterface(&This->IUnknown_inner, riid, ppv);
 }
 
 static ULONG SeekOuter_AddRef(PassThruImpl *This)
 {
     if (This->outer_unk && This->bUnkOuterValid)
         return IUnknown_AddRef(This->outer_unk);
-    return IUnknown_AddRef((IUnknown *)&(This->IUnknown_inner));
+    return IUnknown_AddRef(&This->IUnknown_inner);
 }
 
 static ULONG SeekOuter_Release(PassThruImpl *This)
 {
     if (This->outer_unk && This->bUnkOuterValid)
         return IUnknown_Release(This->outer_unk);
-    return IUnknown_Release((IUnknown *)&(This->IUnknown_inner));
+    return IUnknown_Release(&This->IUnknown_inner);
 }
 
 static HRESULT WINAPI SeekingPassThru_QueryInterface(ISeekingPassThru *iface, REFIID riid, LPVOID *ppvObj)
diff --git a/dlls/strmbase/renderer.c b/dlls/strmbase/renderer.c
index fa2545be6dc..366e6d61167 100644
--- a/dlls/strmbase/renderer.c
+++ b/dlls/strmbase/renderer.c
@@ -238,7 +238,8 @@ static const BaseInputPinFuncTable input_BaseInputFuncTable = {
 };
 
 
-HRESULT WINAPI BaseRenderer_Init(BaseRenderer * This, const IBaseFilterVtbl *Vtbl, IUnknown *pUnkOuter, const CLSID *pClsid, DWORD_PTR DebugInfo, const BaseRendererFuncTable* pBaseFuncsTable)
+HRESULT WINAPI BaseRenderer_Init(BaseRenderer * This, const IBaseFilterVtbl *Vtbl, IUnknown *pUnkOuter, const CLSID *pClsid,
+    DWORD_PTR DebugInfo, const BaseRendererFuncTable* pBaseFuncsTable)
 {
     PIN_INFO piInput;
     HRESULT hr;
@@ -257,7 +258,8 @@ HRESULT WINAPI BaseRenderer_Init(BaseRenderer * This, const IBaseFilterVtbl *Vtb
 
     if (SUCCEEDED(hr))
     {
-        hr = CreatePosPassThru(pUnkOuter ? pUnkOuter: (IUnknown*)This, TRUE, &This->pInputPin->pin.IPin_iface, &This->pPosition);
+        hr = CreatePosPassThru(pUnkOuter ? pUnkOuter: (IUnknown *)&This->filter.IBaseFilter_iface, TRUE,
+                &This->pInputPin->pin.IPin_iface, &This->pPosition);
         if (FAILED(hr))
             return hr;
 
diff --git a/dlls/strmbase/transform.c b/dlls/strmbase/transform.c
index 65b6052c7c1..accb4f1702d 100644
--- a/dlls/strmbase/transform.c
+++ b/dlls/strmbase/transform.c
@@ -241,7 +241,8 @@ static HRESULT TransformFilter_Init(const IBaseFilterVtbl *pVtbl, const CLSID* p
     {
         ISeekingPassThru *passthru;
         pTransformFilter->seekthru_unk = NULL;
-        hr = CoCreateInstance(&CLSID_SeekingPassThru, (IUnknown*)pTransformFilter, CLSCTX_INPROC_SERVER, &IID_IUnknown, (void**)&pTransformFilter->seekthru_unk);
+        hr = CoCreateInstance(&CLSID_SeekingPassThru, (IUnknown *)&pTransformFilter->filter.IBaseFilter_iface, CLSCTX_INPROC_SERVER,
+                &IID_IUnknown, (void **)&pTransformFilter->seekthru_unk);
         if (SUCCEEDED(hr))
         {
             IUnknown_QueryInterface(pTransformFilter->seekthru_unk, &IID_ISeekingPassThru, (void**)&passthru);