Failing gapless playback with pygst

gistfile1.py

import pygst                                                                     
pygst.require("0.10")                                                            
import gst                                                                       
import sys                                                                       
import gobject                                                                   
                                                                                 
class Player:                                                                    
    def __init__(self, filename):                                                
        self.filename = filename                                                 
        self.player = gst.element_factory_make("playbin2", "player")             
        self.player.set_property("uri", filename)                                
        self.player.connect("about-to-finish", self.on_about_to_finish)          
                                                                                 
    def run(self):                                                               
        self.player.set_state(gst.STATE_PLAYING)                                 
        loop = gobject.MainLoop()                                                
        loop.run()                                                               
                                                                                 
    def on_about_to_finish(self, player):                                        
        print 'about-to-finish'                                                  
        player.set_property("uri", self.filename)                                
                                                                                 
if __name__ == "__main__":                                                       
    gobject.threads_init()                                                       
    player = Player("file:///usr/share/gnome-games/sounds/gnometris.ogg")        
    player.run()