QtPlayer: getting frame in audio/video threads safely

include/ReaderBase.h

@@ -88,6 +88,8 @@ namespace openshot
 	 */
 	class ReaderBase
 	{
+	    CriticalSection getFrameCriticalSection;
+
 	public:
 		/// Information about the current media file
 		ReaderInfo info;
@@ -106,6 +108,9 @@ namespace openshot
 		/// @param[in] number The frame number that is requested.
 		virtual tr1::shared_ptr<Frame> GetFrame(int number) = 0;
 
+	    /// A thread safe version of GetFrame.
+	    tr1::shared_ptr<Frame> GetFrameSafe(int number);
+
 		/// Test method to draw a bitmap on a Qt QGraphicsScene
 		void DrawFrameOnScene(string path, long _graphics_scene_address);
 

src/AudioReaderSource.cpp

@@ -82,7 +82,7 @@ void AudioReaderSource::GetMoreSamplesFromReader() {
 		if (frame_position == 0) {
 			try {
 				// Get frame object
-				frame = reader->GetFrame(frame_number++);
+				frame = reader->GetFrameSafe(frame_number++);
 
 			} catch (const ReaderClosed & e) {
 			break;

src/Qt/PlayerPrivate.cpp

@@ -90,7 +90,7 @@ namespace openshot
     tr1::shared_ptr<Frame> PlayerPrivate::getFrame()
     {
 	try {
-	    return reader->GetFrame(position++);
+	    return reader->GetFrameSafe(position++);
 	} catch (const ReaderClosed & e) {
 	    // ...
 	} catch (const TooManySeeks & e) {

src/ReaderBase.cpp

@@ -215,5 +215,8 @@ void ReaderBase::DrawFrameOnScene(string path, long _graphics_scene_address) {
 
 }
 
-
-
+tr1::shared_ptr<Frame> ReaderBase::GetFrameSafe(int number)
+{
+    const GenericScopedLock<CriticalSection> lock(getFrameCriticalSection);
+    return GetFrame(number);
+}