[PATCH 0/2] MR2012: mf/session: Avoid dropping samples delivered from transform in session_request_sample_from_node().

[Paul Gofman (＠gofman)]

session_request_sample() calls session_request_sample_from_node() and increments sink.requests only if that succeeds. But session_request_sample_from_node() calls session_deliver_sample_to_node() synchronously for MF_TOPOLOGY_TRANSFORM_NODE if there are output samples available. Then, if sink.requests is zero before this session_request_sample() call that sample is silently dropped.

It might not be easily noticeable currently, but I have a patchset which implements _ProcessMessage(MFT_MESSAGE_COMMAND_DRAIN) needed for some games (and also improving end of playback by fully delivering output including few last frames). And currently if session_deliver_sample_to_node() performs drain and that drain produces any samples we get a data sample processed but end marker silently dropped resulting in hanging session. That market gets to session_request_sample / session_request_sample_from_node but gets dropped in session_deliver_sample_to_node due to the reason first patch is fixing.

Thus also the second patch. I am not sure it is strictly needed, but the current handling of that seems fragile to me, I suppose we shouldn't ever drop markers.

[PATCH 2/2] mf: Never drop markers in session_deliver_sample_to_node().

[Paul Gofman]

From: Paul Gofman

---
 dlls/mf/session.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/dlls/mf/session.c b/dlls/mf/session.c
index 85baf07d05a..adda37e8df7 100644
--- a/dlls/mf/session.c
+++ b/dlls/mf/session.c
@@ -3162,6 +3162,10 @@ static void session_deliver_sample_to_node(struct media_session *session, IMFTop
     switch (node_type)
     {
         case MF_TOPOLOGY_OUTPUT_NODE:
+            if (!sample && FAILED(hr = IMFStreamSink_PlaceMarker(topo_node->object.sink_stream, MFSTREAMSINK_MARKER_ENDOFSEGMENT,
+                    NULL, NULL)))
+                WARN("Failed to place sink marker, hr %#lx.\n", hr);
+
             if (topo_node->u.sink.requests)
             {
                 if (sample)
@@ -3169,11 +3173,6 @@ static void session_deliver_sample_to_node(struct media_session *session, IMFTop
                     if (FAILED(hr = IMFStreamSink_ProcessSample(topo_node->object.sink_stream, sample)))
                         WARN("Stream sink failed to process sample, hr %#lx.\n", hr);
                 }
-                else if (FAILED(hr = IMFStreamSink_PlaceMarker(topo_node->object.sink_stream, MFSTREAMSINK_MARKER_ENDOFSEGMENT,
-                        NULL, NULL)))
-                {
-                    WARN("Failed to place sink marker, hr %#lx.\n", hr);
-                }
                 topo_node->u.sink.requests--;
             }
             break;

[PATCH 1/2] mf: Increment requests before session_request_sample_from_node() in session_request_sample().

[Paul Gofman]

From: Paul Gofman

---
 dlls/mf/session.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dlls/mf/session.c b/dlls/mf/session.c
index b2371763150..85baf07d05a 100644
--- a/dlls/mf/session.c
+++ b/dlls/mf/session.c
@@ -3388,8 +3388,9 @@ static void session_request_sample(struct media_session *session, IMFStreamSink
         return;
     }

-    if (SUCCEEDED(session_request_sample_from_node(session, upstream_node, upstream_output)))
-        sink_node->u.sink.requests++;
+    sink_node->u.sink.requests++;
+    if (FAILED(session_request_sample_from_node(session, upstream_node, upstream_output)))
+        sink_node->u.sink.requests--;
     IMFTopologyNode_Release(upstream_node);
 }