diff --git a/dlls/amstream/amstream.c b/dlls/amstream/amstream.c
index 293e2b917c..a78abee5d6 100644
--- a/dlls/amstream/amstream.c
+++ b/dlls/amstream/amstream.c
@@ -397,7 +397,7 @@ static HRESULT WINAPI IAMMultiMediaStreamImpl_AddMediaStream(IAMMultiMediaStream
     return hr;
 }
 
-static HRESULT WINAPI IAMMultiMediaStreamImpl_OpenFile(IAMMultiMediaStream* iface, LPCWSTR pszFileName, DWORD dwFlags)
+static HRESULT WINAPI IAMMultiMediaStreamImpl_OpenFile(IAMMultiMediaStream* iface, LPCWSTR filename, DWORD flags)
 {
     IAMMultiMediaStreamImpl *This = impl_from_IAMMultiMediaStream(iface);
     HRESULT ret = S_OK;
@@ -407,14 +407,17 @@ static HRESULT WINAPI IAMMultiMediaStreamImpl_OpenFile(IAMMultiMediaStream* ifac
     PIN_DIRECTION pin_direction;
     const WCHAR sourceW[] = {'S','o','u','r','c','e',0};
 
-    TRACE("(%p/%p)->(%s,%x)\n", This, iface, debugstr_w(pszFileName), dwFlags);
+    TRACE("(%p/%p)->(%s,%x)\n", This, iface, debugstr_w(filename), flags);
+
+    if (!filename)
+        return E_POINTER;
 
     /* If Initialize was not called before, we do it here */
     if (!This->pFilterGraph)
         ret = IAMMultiMediaStream_Initialize(iface, STREAMTYPE_READ, 0, NULL);
 
     if (SUCCEEDED(ret))
-        ret = IGraphBuilder_AddSourceFilter(This->pFilterGraph, pszFileName, sourceW, &BaseFilter);
+        ret = IGraphBuilder_AddSourceFilter(This->pFilterGraph, filename, sourceW, &BaseFilter);
 
     if (SUCCEEDED(ret))
         ret = IBaseFilter_EnumPins(BaseFilter, &EnumPins);
diff --git a/dlls/amstream/tests/amstream.c b/dlls/amstream/tests/amstream.c
index 6a198e01c9..5121b35f82 100644
--- a/dlls/amstream/tests/amstream.c
+++ b/dlls/amstream/tests/amstream.c
@@ -412,6 +412,10 @@ static void test_media_streams(void)
         }
     }
 
+    /* Test open file with no filename */
+    hr = IAMMultiMediaStream_OpenFile(pams, NULL, 0);
+    ok(hr == E_POINTER, "IAMMultiMediaStream_OpenFile returned %x instead of %x\n", hr, E_POINTER);
+
     if (video_stream)
         IMediaStream_Release(video_stream);
     if (audio_stream)