[PATCH 0/1] MR8462: mfmediaengine: Delay old presentation clearing until new toplogy was set.

[Bernhard Kölbl (＠besentv)]

Shutting down the media source, while it is still in an active topology, causes Windows' media session to fully shut down. To avoid this, only clear the old presentation on release, shutdown or when a new topology was successfully set.

(FWIW: This solution is definitely not the greatest)

[PATCH 1/1] mfmediaengine: Delay old presentation clearing until new toplogy was set.

[Bernhard Kölbl]

From: Bernhard Kölbl

Shutting down the media source, while it is still in an active topology, causes Windows' media session to fully shut down. To avoid this, only clear the old presentation on release, shutdown or when a new topology was successfully set.
---
 dlls/mfmediaengine/main.c | 40 ++++++++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/dlls/mfmediaengine/main.c b/dlls/mfmediaengine/main.c
index aab5fd64aa2..0c3a4efc1e2 100644
--- a/dlls/mfmediaengine/main.c
+++ b/dlls/mfmediaengine/main.c
@@ -164,13 +164,13 @@ struct media_engine
     IMFSourceResolver *resolver;
     IMFMediaEngineExtension *extension;
     BSTR current_source;
-    struct
+    struct media_engine_presentation
     {
         IMFMediaSource *source;
         IMFPresentationDescriptor *pd;
         PROPVARIANT start_position;
         struct video_frame_sink *frame_sink;
-    } presentation;
+    } presentation, old_presentation;
     struct effects video_effects;
     struct effects audio_effects;
     struct
@@ -913,6 +913,7 @@ static HRESULT WINAPI media_engine_callback_GetParameters(IMFAsyncCallback *ifac
 }

static HRESULT media_engine_set_current_time(struct media_engine *engine, double seektime);
+static void media_engine_clear_presentation(struct media_engine_presentation *presentation, CRITICAL_SECTION *engine_cs);

static HRESULT WINAPI media_engine_session_events_Invoke(IMFAsyncCallback *iface, IMFAsyncResult *result)
 {
@@ -965,6 +966,7 @@ static HRESULT WINAPI media_engine_session_events_Invoke(IMFAsyncCallback *iface

EnterCriticalSection(&engine->cs);

+            media_engine_clear_presentation(&engine->old_presentation, &engine->cs);
             media_engine_apply_volume(engine);

engine->ready_state = MF_MEDIA_ENGINE_READY_HAVE_METADATA;
@@ -1223,26 +1225,26 @@ static HRESULT media_engine_create_video_renderer(struct media_engine *engine, I
 }

/* must be called with engine->cs held */
-static void media_engine_clear_presentation(struct media_engine *engine)
+static void media_engine_clear_presentation(struct media_engine_presentation *presentation, CRITICAL_SECTION *engine_cs)
 {
-    if (engine->presentation.source)
+    if (presentation->source)
     {
         /* critical section can not be held during shutdown, as shut down requires all pending
          * callbacks to complete, and some callbacks require this cs */
-        LeaveCriticalSection(&engine->cs);
-        IMFMediaSource_Shutdown(engine->presentation.source);
-        EnterCriticalSection(&engine->cs);
-        IMFMediaSource_Release(engine->presentation.source);
+        LeaveCriticalSection(engine_cs);
+        IMFMediaSource_Shutdown(presentation->source);
+        EnterCriticalSection(engine_cs);
+        IMFMediaSource_Release(presentation->source);
     }
-    if (engine->presentation.pd)
-        IMFPresentationDescriptor_Release(engine->presentation.pd);
-    if (engine->presentation.frame_sink)
+    if (presentation->pd)
+        IMFPresentationDescriptor_Release(presentation->pd);
+    if (presentation->frame_sink)
     {
-        video_frame_sink_release(engine->presentation.frame_sink);
-        engine->presentation.frame_sink = NULL;
+        video_frame_sink_release(presentation->frame_sink);
+        presentation->frame_sink = NULL;
     }

-    memset(&engine->presentation, 0, sizeof(engine->presentation));
+    memset(presentation, 0, sizeof(*presentation));
 }

static void media_engine_clear_effects(struct effects *effects)
@@ -1268,8 +1270,10 @@ static HRESULT media_engine_create_topology(struct media_engine *engine, IMFMedi
     UINT64 duration;
     HRESULT hr;

+    memcpy(&engine->old_presentation, &engine->presentation, sizeof(struct media_engine_presentation));
+    memset(&engine->presentation, 0, sizeof(engine->presentation));
+
     media_engine_release_video_frame_resources(engine);
-    media_engine_clear_presentation(engine);

if (FAILED(hr = IMFMediaSource_CreatePresentationDescriptor(source, &pd)))
         return hr;
@@ -1550,7 +1554,8 @@ static void free_media_engine(struct media_engine *engine)
     media_engine_clear_effects(&engine->audio_effects);
     media_engine_clear_effects(&engine->video_effects);
     media_engine_release_video_frame_resources(engine);
-    media_engine_clear_presentation(engine);
+    media_engine_clear_presentation(&engine->presentation, &engine->cs);
+    media_engine_clear_presentation(&engine->old_presentation, &engine->cs);
     if (engine->device_manager)
     {
         IMFDXGIDeviceManager_CloseDeviceHandle(engine->device_manager, engine->device_handle);
@@ -2375,7 +2380,8 @@ static HRESULT WINAPI media_engine_Shutdown(IMFMediaEngineEx *iface)
     else
     {
         media_engine_set_flag(engine, FLAGS_ENGINE_SHUT_DOWN, TRUE);
-        media_engine_clear_presentation(engine);
+        media_engine_clear_presentation(&engine->presentation, &engine->cs);
+        media_engine_clear_presentation(&engine->old_presentation, &engine->cs);
         /* critical section can not be held during shutdown, as shut down requires all pending
          * callbacks to complete, and some callbacks require this cs */
         LeaveCriticalSection(&engine->cs);

[Nikolay Sivov (＠nsivov)]

Could you explain step by step what application is doing?