lets try this

bin/oxframe

@@ -2,6 +2,8 @@
 # -*- coding: utf-8 -*-
 # vi:si:et:sw=4:sts=4:ts=4
 # GPL 2008
+import gobject
+gobject.threads_init()
 
 import os
 import sys

oxgst/video.py

@@ -45,16 +45,22 @@ class Video(gst.Pipeline):
 
         self.sbin.connect('pad-added', self._sbinPadAddedCb)
         self.set_state(gst.STATE_PAUSED)
-        self.get_state()
-        self.width = self.sink.width
-        self.height = self.sink.height
-        self.framerate = self.sink.framerate
-        self.getDuration()
-        self.frames = int((float(self.duration) / gst.SECOND) * float(self.framerate))
+
 
     def _sbinPadAddedCb(self, unused_sbin, pad):
         self.log("pad : %s" % pad)
+        pad.set_blocked_async (True, self._pad_blocked_cb)
+
+    def _pad_blocked_cb(self, pad, blocked):
+        if blocked:
+            #duration
+            if self.duration < 0:
+                q = gst.query_new_duration(gst.FORMAT_TIME)
+                if pad.query(q):
+                  format, self.duration = q.parse_duration()
+
             pad.link(self.csp.get_pad("sink"))
+            pad.set_blocked_async (False, self._pad_blocked_cb)
 
     def _frameCb(self, unused_thsink, frame, timestamp):
         self.log("image:%s, timestamp:%s" % (frame, gst.TIME_ARGS(timestamp)))
@@ -73,15 +79,6 @@ class Video(gst.Pipeline):
             # still some more thumbnails to process
             gobject.idle_add(self._getFrame, self.queue.pop(0))
 
-    def getDuration(self):
-        if self.duration < 0:
-            pads = self.sink.sink_pads()
-            q = gst.query_new_duration(gst.FORMAT_TIME)
-            for pad in pads:
-                if pad.get_peer() and pad.get_peer().query(q):
-                  format, self.duration = q.parse_duration()
-        return self.duration
-
     def getFrame(self, timestamp, callback):
         """
             Queue a frame request for the given timestamp,
@@ -90,12 +87,12 @@ class Video(gst.Pipeline):
         """
         
         self.log("timestamp %s" % gst.TIME_ARGS(timestamp))
-        if self.duration < 0:
-            self.getDuration()
+        #if self.duration < 0:
+        #    self.getDuration()
         
-        if timestamp > self.duration:
-            self.log("timestamp %s > duration %s" % (timestamp, self.duration))
-            return False
+        #if timestamp > self.duration:
+        #    self.log("timestamp %s > duration %s" % (timestamp, self.duration))
+        #    return False
 
         self.callback[timestamp] = callback
 
@@ -111,6 +108,11 @@ class Video(gst.Pipeline):
     def _getFrame(self, timestamp):
         if not self._ready:
             return
+        if timestamp > self.duration:
+            if self.mainloop:
+                self.mainloop.quit()
+            return
+
         self.log("timestamp : %s" % gst.TIME_ARGS(timestamp))
         self.seek(1.0, gst.FORMAT_TIME, gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
                   gst.SEEK_TYPE_SET, timestamp,
@@ -118,13 +120,13 @@ class Video(gst.Pipeline):
         return False
 
     def frame(self, timestamp):
-        mainloop = gobject.MainLoop()
+        self.mainloop = gobject.MainLoop()
         self._frames[timestamp] = None
         def callback(frame, timestamp):
             self._frames[timestamp] = frame
-            mainloop.quit()
+            self.mainloop.quit()
         if self.getFrame(timestamp, callback):
-            mainloop.run()
+            self.mainloop.run()
         frame = self._frames[timestamp]
         del self._frames[timestamp]
         return frame