diff --git a/dlls/quartz/memallocator.c b/dlls/quartz/memallocator.c
index b7dff8cdabe..91c23736fd0 100644
--- a/dlls/quartz/memallocator.c
+++ b/dlls/quartz/memallocator.c
@@ -686,7 +686,7 @@ static HRESULT WINAPI StdMediaSample2_SetMediaType(IMediaSample2 * iface, AM_MED
         This->props.pMediaType = NULL;
     }
     if (!pMediaType)
-        return S_FALSE;
+        return S_OK;
     if (!(This->props.pMediaType = CoTaskMemAlloc(sizeof(AM_MEDIA_TYPE))))
         return E_OUTOFMEMORY;
 
diff --git a/dlls/quartz/tests/memallocator.c b/dlls/quartz/tests/memallocator.c
index 3868312aac9..9bbfd425cfa 100644
--- a/dlls/quartz/tests/memallocator.c
+++ b/dlls/quartz/tests/memallocator.c
@@ -487,7 +487,7 @@ static void test_sample_properties(void)
     ok(!mt, "Got media type %p.\n", mt);
 
     hr = IMediaSample_SetMediaType(sample, NULL);
-    todo_wine ok(hr == S_OK, "Got hr %#x.\n", hr);
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
 
     mt = (AM_MEDIA_TYPE *)0xdeadbeef;
     hr = IMediaSample_GetMediaType(sample, &mt);
@@ -513,7 +513,7 @@ static void test_sample_properties(void)
     ok(!memcmp(props.pMediaType, &expect_mt, sizeof(AM_MEDIA_TYPE)), "Media types didn't match.\n");
 
     hr = IMediaSample_SetMediaType(sample, NULL);
-    todo_wine ok(hr == S_OK, "Got hr %#x.\n", hr);
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
 
     mt = (AM_MEDIA_TYPE *)0xdeadbeef;
     hr = IMediaSample_GetMediaType(sample, &mt);