diff --git a/dlls/wmvcore/reader.c b/dlls/wmvcore/reader.c
index 6041c567e95..6945f10a659 100644
--- a/dlls/wmvcore/reader.c
+++ b/dlls/wmvcore/reader.c
@@ -176,7 +176,12 @@ static HRESULT WINAPI WMReader_GetOutputCount(IWMReader *iface, DWORD *outputs)
 {
     WMReader *This = impl_from_IWMReader(iface);
     FIXME("(%p)->(%p)\n", This, outputs);
-    return E_NOTIMPL;
+
+    if(!outputs)
+        return E_INVALIDARG;
+
+    *outputs = 0;
+    return S_OK;
 }
 
 static HRESULT WINAPI WMReader_GetOutputProps(IWMReader *iface, DWORD output_num, IWMOutputMediaProps **output)