diff --git a/MediaPlayer.cpp b/MediaPlayer.cpp
index ccbb51b..7cd4505 100644
--- a/MediaPlayer.cpp
+++ b/MediaPlayer.cpp
@@ -130,6 +130,11 @@ void MediaPlayer::open(string path)
 
 void MediaPlayer::execute_open() 
 {
+    // Create the simplest gstreamer pipeline possible :
+    //         " uridecodebin uri=file:///path_to_file/filename.mp4 ! videoconvert ! appsink "
+    // equivalent to gst-launch-1.0 uridecodebin uri=file:///path_to_file/filename.mp4 ! videoconvert ! ximagesink
+
+
     // build string describing pipeline
     string description = "uridecodebin uri=" + uri_ + " name=decoder !";
     if (interlaced_)
diff --git a/MediaPlayer.h b/MediaPlayer.h
index c4079fb..79db61b 100644
--- a/MediaPlayer.h
+++ b/MediaPlayer.h
@@ -19,7 +19,7 @@ class Visitor;
 
 #define MAX_PLAY_SPEED 20.0
 #define MIN_PLAY_SPEED 0.1
-#define N_VFRAME 3
+#define N_VFRAME 2
 
 struct TimeCounter {