Force GL to block after the current frame instead during the next frame

app/streaming/video/ffmpeg-renderers/eglvid.h

@@ -33,6 +33,7 @@ private:
     unsigned int m_VAO;
     int m_ColorSpace;
     bool m_ColorFull;
+    bool m_BlockingSwapBuffers;
     PFNGLEGLIMAGETARGETTEXTURE2DOESPROC m_glEGLImageTargetTexture2DOES;
     PFNGLGENVERTEXARRAYSOESPROC m_glGenVertexArraysOES;
     PFNGLBINDVERTEXARRAYOESPROC m_glBindVertexArrayOES;