returned to AVFilter solution

project/clip.cpp

@@ -29,6 +29,7 @@ Clip::Clip(Sequence* s) :
     closing_transition(NULL),
 	pkt(new AVPacket()),
 	replaced(false),
+	filter_graph(NULL),
 	texture(NULL),
 	fbo(NULL),
     autoscale(config.autoscale_by_default)

project/clip.h

@@ -21,6 +21,8 @@ struct AVFrame;
 struct AVPacket;
 struct SwsContext;
 struct SwrContext;
+struct AVFilterGraph;
+struct AVFilterContext;
 class QOpenGLTexture;
 
 struct ClipCache {
@@ -98,8 +100,13 @@ struct Clip
     QMutex lock;
     QMutex open_lock;
 
+	// converters/filters
+	AVFilterGraph* filter_graph;
+	AVFilterContext* buffersink_ctx;
+	AVFilterContext* buffersrc_ctx;
+
     // video playback variables
-	SwsContext* sws_ctx;
+//	SwsContext* sws_ctx;
 	QOpenGLFramebufferObject** fbo;
     QOpenGLTexture* texture;
     long texture_frame;