[PATCH v2 0/1] 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.

--
  v2: mf/session: Avoid dropping samples delivered from transform in session_request_sample_from_node().
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/2012

[PATCH v2 1/1] mf/session: Avoid dropping samples delivered from transform in session_request_sample_from_node().

[Paul Gofman]

From: Paul Gofman <pgofman(a)codeweavers.com>

---
 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);
 }
 
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/2012

[Paul Gofman (＠gofman)]

v2:
 - dropped the second patch (as per discussion with Nikolay, delivering unsolicited marker is likely incorrect);
 - renamed the first patch.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/2012#note_23762