def durationSeconds(self):
        """
        Returns the runtime duration of the video stream as a floating point number of seconds.
        Returns 0.0 if not a video stream.
        """
        f=0.0
        if self.isVideo() or self.isAudio():
            if self.__dict__['duration']:
                try:
                    f=float(self.__dict__['duration'])
                except Exception as e:
                    print "None numeric duration"
        return f
Returns the runtime duration of the video stream as a floating point number of seconds.
        Returns 0.0 if not a video stream.