diff --git a/dlls/amstream/multimedia.c b/dlls/amstream/multimedia.c
index 07c037505e1..be8fd4ecbfc 100644
--- a/dlls/amstream/multimedia.c
+++ b/dlls/amstream/multimedia.c
@@ -298,6 +298,16 @@ static HRESULT WINAPI multimedia_stream_GetFilter(IAMMultiMediaStream *iface,
     return S_OK;
 }
 
+static void add_stream(struct multimedia_stream *mmstream, IAMMediaStream *stream, IMediaStream **ret_stream)
+{
+    IMediaStreamFilter_AddMediaStream(mmstream->filter, stream);
+    if (ret_stream)
+    {
+        *ret_stream = (IMediaStream *)stream;
+        IMediaStream_AddRef(*ret_stream);
+    }
+}
+
 static HRESULT WINAPI multimedia_stream_AddMediaStream(IAMMultiMediaStream *iface,
         IUnknown *stream_object, const MSPID *PurposeId, DWORD dwFlags, IMediaStream **ret_stream)
 {
@@ -309,9 +319,6 @@ static HRESULT WINAPI multimedia_stream_AddMediaStream(IAMMultiMediaStream *ifac
     TRACE("mmstream %p, stream_object %p, id %s, flags %#x, ret_stream %p.\n",
             This, stream_object, debugstr_guid(PurposeId), dwFlags, ret_stream);
 
-    if (!IsEqualGUID(PurposeId, &MSPID_PrimaryVideo) && !IsEqualGUID(PurposeId, &MSPID_PrimaryAudio))
-        return MS_E_PURPOSEID;
-
     if (IMediaStreamFilter_GetMediaStream(This->filter, PurposeId, &stream) == S_OK)
     {
         IMediaStream_Release(stream);
@@ -343,19 +350,43 @@ static HRESULT WINAPI multimedia_stream_AddMediaStream(IAMMultiMediaStream *ifac
         return hr;
     }
 
+    if (stream_object)
+    {
+        hr = IUnknown_QueryInterface(stream_object, &IID_IAMMediaStream, (void **)&pStream);
+        if (SUCCEEDED(hr))
+        {
+            MSPID stream_id;
+            hr = IAMMediaStream_GetInformation(pStream, &stream_id, NULL);
+            if (SUCCEEDED(hr))
+            {
+                if (IsEqualGUID(PurposeId, &stream_id))
+                {
+                    add_stream(This, pStream, ret_stream);
+                    hr = S_OK;
+                }
+                else
+                {
+                    hr = MS_E_PURPOSEID;
+                }
+            }
+
+            IAMMediaStream_Release(pStream);
+
+            return hr;
+        }
+    }
+
     if (IsEqualGUID(PurposeId, &MSPID_PrimaryVideo))
         hr = ddraw_stream_create((IMultiMediaStream*)iface, PurposeId, stream_object, This->type, &pStream);
-    else
+    else if (IsEqualGUID(PurposeId, &MSPID_PrimaryAudio))
         hr = audio_stream_create((IMultiMediaStream*)iface, PurposeId, stream_object, This->type, &pStream);
+    else
+        return MS_E_PURPOSEID;
 
     if (SUCCEEDED(hr))
     {
-        /* Add stream to the media stream filter */
-        IMediaStreamFilter_AddMediaStream(This->filter, pStream);
-        if (ret_stream)
-            *ret_stream = (IMediaStream *)pStream;
-        else
-            IAMMediaStream_Release(pStream);
+        add_stream(This, pStream, ret_stream);
+        IAMMediaStream_Release(pStream);
     }
 
     return hr;
diff --git a/dlls/amstream/tests/amstream.c b/dlls/amstream/tests/amstream.c
index a55884d8abf..09686cfcf4d 100644
--- a/dlls/amstream/tests/amstream.c
+++ b/dlls/amstream/tests/amstream.c
@@ -684,21 +684,21 @@ static void test_add_stream(void)
     ok(hr == MS_E_PURPOSEID, "Got hr %#x.\n", hr);
 
     hr = IAMMultiMediaStream_AddMediaStream(mmstream, (IUnknown *)&teststream, &test_mspid, 0, &stream);
-    todo_wine ok(hr == S_OK, "Got hr %#x.\n", hr);
-    todo_wine ok(stream == (IMediaStream *)&teststream, "Streams didn't match.\n");
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
+    ok(stream == (IMediaStream *)&teststream, "Streams didn't match.\n");
     if (hr == S_OK) IMediaStream_Release(stream);
     todo_wine ok(teststream_mmstream == mmstream, "IAMMultiMediaStream objects didn't match.\n");
-    todo_wine ok(teststream_filter == stream_filter, "IMediaStreamFilter objects didn't match.\n");
+    ok(teststream_filter == stream_filter, "IMediaStreamFilter objects didn't match.\n");
     todo_wine ok(!!teststream_graph, "Expected a non-NULL graph.\n");
 
     check_enum_stream(mmstream, stream_filter, 0, video_stream);
     check_enum_stream(mmstream, stream_filter, 1, audio_stream);
-    todo_wine check_enum_stream(mmstream, stream_filter, 2, (IMediaStream *)&teststream);
+    check_enum_stream(mmstream, stream_filter, 2, (IMediaStream *)&teststream);
     check_enum_stream(mmstream, stream_filter, 3, NULL);
 
     check_get_stream(mmstream, stream_filter, &MSPID_PrimaryVideo, video_stream);
     check_get_stream(mmstream, stream_filter, &MSPID_PrimaryAudio, audio_stream);
-    todo_wine check_get_stream(mmstream, stream_filter, &test_mspid, (IMediaStream *)&teststream);
+    check_get_stream(mmstream, stream_filter, &test_mspid, (IMediaStream *)&teststream);
 
     hr = IAMMultiMediaStream_AddMediaStream(mmstream, NULL, &MSPID_PrimaryVideo, 0, &stream);
     ok(hr == MS_E_PURPOSEID, "Got hr %#x.\n", hr);
@@ -839,7 +839,7 @@ static void test_add_stream(void)
     ok(hr == MS_E_PURPOSEID, "Got hr %#x.\n", hr);
     hr = IAMMultiMediaStream_AddMediaStream(mmstream, NULL, &test_mspid,
             AMMSF_ADDDEFAULTRENDERER, &audio_stream);
-    todo_wine ok(hr == E_INVALIDARG, "Got hr %#x.\n", hr);
+    ok(hr == E_INVALIDARG, "Got hr %#x.\n", hr);
 
     IMediaStreamFilter_Release(stream_filter);
     ref = IAMMultiMediaStream_Release(mmstream);