bmd: keep notification interface in BMDNotificationCallback

I am not entierly sure if releasing IDeckLinkNotification in register
fuction actually doesn't cleanup the state. It seems it does not  but
just to be sure.

Author: MartinPulec

src/blackmagic_common.cpp

@@ -1355,11 +1355,14 @@ print_status_item(IDeckLinkStatus *deckLinkStatus, BMDDeckLinkStatusID prop)
 }
 
 // from BMD SDK sample StatusMonitor.cpp
-class NotificationCallback : public IDeckLinkNotificationCallback
+class BMDNotificationCallback : public IDeckLinkNotificationCallback
 {
       public:
-        explicit NotificationCallback(IDeckLinkStatus *deckLinkStatus)
-            : m_deckLinkStatus(deckLinkStatus), m_refCount(1)
+        explicit BMDNotificationCallback(
+            IDeckLinkStatus       *deckLinkStatus,
+            IDeckLinkNotification *deckLinkNotification)
+            : m_deckLinkStatus(deckLinkStatus),
+              m_deckLinkNotification(deckLinkNotification), m_refCount(1)
 
         {
                 m_deckLinkStatus->AddRef();
@@ -1404,10 +1407,18 @@ class NotificationCallback : public IDeckLinkNotificationCallback
         }
 
       private:
-        IDeckLinkStatus   *m_deckLinkStatus;
-        std::atomic<ULONG> m_refCount;
+        IDeckLinkStatus       *m_deckLinkStatus;
+        IDeckLinkNotification *m_deckLinkNotification;
+        std::atomic<ULONG>     m_refCount;
 
-        virtual ~NotificationCallback() { m_deckLinkStatus->Release(); }
+        virtual ~BMDNotificationCallback()
+        {
+                m_deckLinkNotification->Unsubscribe(bmdStatusChanged, this);
+                m_deckLinkStatus->Release();
+                m_deckLinkNotification->Release();
+        }
+
+      public:
 };
 
 /**
@@ -1425,7 +1436,7 @@ class NotificationCallback : public IDeckLinkNotificationCallback
  * @todo
  * Print some useful information also normally (non-IP devices).
  */
-IDeckLinkNotificationCallback *
+BMDNotificationCallback *
 bmd_print_status_subscribe_notify(IDeckLink *deckLink, bool capture)
 {
         IDeckLinkProfileAttributes *deckLinkAttributes = nullptr;
@@ -1474,8 +1485,9 @@ bmd_print_status_subscribe_notify(IDeckLink *deckLink, bool capture)
                 return nullptr;
         }
 
-        auto *notificationCallback = new NotificationCallback(deckLinkStatus);
-        assert(notificationCallback!= nullptr);
+        auto *notificationCallback =
+            new BMDNotificationCallback(deckLinkStatus, deckLinkNotification);
+        assert(notificationCallback != nullptr);
 
         result = deckLinkNotification->Subscribe(bmdStatusChanged,
                                                  notificationCallback);
@@ -1488,32 +1500,16 @@ bmd_print_status_subscribe_notify(IDeckLink *deckLink, bool capture)
                 return nullptr;
         }
 
-        deckLinkNotification->Release();;
-
         return notificationCallback;
 }
 void
-bmd_unsubscribe_notify(IDeckLink                     *deckLink,
-                       IDeckLinkNotificationCallback *notificationCallback) {
+bmd_unsubscribe_notify(BMDNotificationCallback *notificationCallback)
+{
         if (notificationCallback == nullptr) {
                 return;
         }
 
-        // Obtain the notification interface
-        IDeckLinkNotification *deckLinkNotification = nullptr;
-        HRESULT result = deckLink->QueryInterface(IID_IDeckLinkNotification,
-                                          (void **) &deckLinkNotification);
-        if (result != S_OK) {
-                MSG(ERROR,
-                    "Could not obtain the IDeckLinkNotification interface - "
-                    "result = %08x; cannot unsubscribe\n",
-                    result);
-                return;
-        }
-        deckLinkNotification->Unsubscribe(bmdStatusChanged,
-                                          notificationCallback);
         notificationCallback->Release();
-        deckLinkNotification->Release();
 }
 
 ADD_TO_PARAM(R10K_FULL_OPT, "* " R10K_FULL_OPT "\n"

src/blackmagic_common.hpp

@@ -190,11 +190,10 @@ using bmd_dev = std::tuple<std::unique_ptr<IDeckLink, void (*)(IDeckLink *)>,
 std::vector<bmd_dev> bmd_get_sorted_devices(bool *com_initialized,
                                             bool  verbose      = true,
                                             bool  natural_sort = false);
-IDeckLinkNotificationCallback *
-bmd_print_status_subscribe_notify(IDeckLink *deckLink, bool capture);
-void
-bmd_unsubscribe_notify(IDeckLink                     *deckLink,
-                       IDeckLinkNotificationCallback *notificationCallback);
+class BMDNotificationCallback;
+BMDNotificationCallback *bmd_print_status_subscribe_notify(IDeckLink *deckLink,
+                                                           bool       capture);
+void bmd_unsubscribe_notify(BMDNotificationCallback *notificationCallback);
 
 #endif // defined BLACKMAGIC_COMMON_HPP
 

src/video_capture/decklink.cpp

@@ -173,7 +173,7 @@ struct device_state {
         unique_ptr<VideoDelegate>  delegate;
         IDeckLinkProfileAttributes *deckLinkAttributes    = nullptr;
         IDeckLinkConfiguration     *deckLinkConfiguration = nullptr;
-        IDeckLinkNotificationCallback *notificationCallback = nullptr;
+        BMDNotificationCallback    *notificationCallback  = nullptr;
         string                      device_id = "0"; // either numeric value or device name
         bool                        audio                 = false; /* wheather we process audio or not */
         struct tile                *tile                  = nullptr;
@@ -1519,8 +1519,7 @@ static void cleanup_common(struct vidcap_decklink_state *s) {
         }
 
         for (int i = 0; i < s->devices_cnt; ++i) {
-                bmd_unsubscribe_notify(s->state[i].deckLink,
-                                       s->state[i].notificationCallback);
+                bmd_unsubscribe_notify(s->state[i].notificationCallback);
                 RELEASE_IF_NOT_NULL(s->state[i].deckLinkConfiguration);
                 RELEASE_IF_NOT_NULL(s->state[i].deckLinkAttributes);
                 RELEASE_IF_NOT_NULL(s->state[i].deckLinkInput);

src/video_display/decklink.cpp

@@ -508,7 +508,7 @@ struct state_decklink {
         IDeckLinkOutput            *deckLinkOutput;
         IDeckLinkConfiguration     *deckLinkConfiguration;
         IDeckLinkProfileAttributes *deckLinkAttributes;
-        IDeckLinkNotificationCallback *notificationCallback = nullptr;
+        BMDNotificationCallback    *notificationCallback = nullptr;
 
         DeckLinkTimecode    *timecode{}; ///< @todo Should be actually allocated dynamically and
                                        ///< its lifespan controlled by AddRef()/Release() methods
@@ -1604,7 +1604,7 @@ static void display_decklink_done(void *state)
                                "DisableVideoOutput");
         }
 
-        bmd_unsubscribe_notify(s->deckLink, s->notificationCallback);
+        bmd_unsubscribe_notify(s->notificationCallback);
         RELEASE_IF_NOT_NULL(s->deckLinkAttributes);
         RELEASE_IF_NOT_NULL(s->deckLinkConfiguration);
         RELEASE_IF_NOT_NULL(s->deckLinkOutput);