Make sure InteropContext outlasts all player instances, track MediaPlayer lifetime and only startup/shutdown MediaFoundation when necessary

Author: axjxwright

samples/SimplePlayback/src/SimplePlaybackApp.cxx

@@ -19,7 +19,6 @@ namespace ui = ImGui;
 class SimplePlaybackApp : public app::App
 {
 public:
-
     void setup ( ) override;
     void update ( ) override;
     void draw ( ) override;
@@ -30,7 +29,7 @@ class SimplePlaybackApp : public app::App
     AX::Video::MediaPlayerRef     _player;
     AX::Video::MediaPlayer::Error _error{ AX::Video::MediaPlayer::Error::NoError };
 
-    bool _hardwareAccelerated{ false };
+    bool _hardwareAccelerated{ true };
     gl::TextureRef _texture;
 };
 

src/Win32/AX-MediaPlayerWin32DXGIRenderPath.cxx

@@ -50,10 +50,16 @@ namespace AX::Video
         bool                            _isValid{ false };
     };
 
+    // @note(andrew): Lazily initialize this but make sure
+    // it hangs around for the remainer of the application
+    // so that it outlives any of the players that depend on
+    // it being alive and valid
+
+    static std::unique_ptr<InteropContext> kInteropContext{ nullptr };
     InteropContext & InteropContext::Get ( )
     {
-        static InteropContext kInstance;
-        return kInstance;
+        if ( !kInteropContext ) kInteropContext.reset ( new InteropContext ( ) );
+        return *kInteropContext;
     }
 
     class DXGIRenderPath::SharedTexture
@@ -218,6 +224,7 @@ namespace AX::Video
         {
             if ( IsLocked() ) wglDXUnlockObjectsNV ( InteropContext::Get ( ).Handle ( ), 1, &_shareHandle );
             wglDXUnregisterObjectNV ( InteropContext::Get ( ).Handle ( ), _shareHandle );
+            _shareHandle = nullptr;
         }
     }
 

src/Win32/AX-MediaPlayerWin32Impl.cxx

@@ -25,6 +25,24 @@ using namespace ci;
 
 namespace
 {
+    static std::atomic_int kNumMediaFoundationInstances = 0;
+
+    static void OnMediaPlayerCreated ( )
+    {
+        if ( kNumMediaFoundationInstances++ == 0 )
+        {
+            MFStartup ( MF_VERSION );
+        }
+    }
+
+    static void OnMediaPlayerDestroyed ( )
+    {
+        if ( --kNumMediaFoundationInstances == 0 )
+        {
+            MFShutdown ( );
+        }
+    }
+
     class MFCallbackBase : public IMFAsyncCallback
     {
     public:
@@ -244,7 +262,7 @@ namespace AX::Video
         , _source ( source )
         , _flags ( flags )
     {
-        MFStartup ( MF_VERSION );
+        OnMediaPlayerCreated ( );
 
         ComPtr<IMFMediaEngineClassFactory> factory;
         if ( SUCCEEDED ( CoCreateInstance ( CLSID_MFMediaEngineClassFactory, nullptr, CLSCTX_INPROC_SERVER, IID_PPV_ARGS ( &factory ) ) ) )
@@ -608,12 +626,15 @@ namespace AX::Video
 
     MediaPlayer::Impl::~Impl ( )
     {
+        _renderPath = nullptr;
+        _hasNewFrame.store ( false );
+
         if ( _mediaEngine )
         {
             _mediaEngine->Shutdown ( );
             _mediaEngine = nullptr;
         }
 
-        MFShutdown ( );
+        OnMediaPlayerDestroyed ( );
     }
 }