yes i am using time_step , but the videos load on the fly.
I would write a code to play all movies for a frame , just for loading them in memory , but the problem is that the same video that was playing before , ends up in lag if its playing again some time later. I am sure its the video codec i will try another way to compress my videos. Currently i used the "windows media Video9 (wmv3)" codec to compress the videos. If i am back home i will try other codecs ...