I am trying to create 1 video file that it size could be change and related to 2 video files. I want to combine video1 with vido2 and obtain only 1 video output and screen siz will be depended video1 and video2. Forexample video1 is 640480 and also video2 is 640480. But i want to change only video2 size (320*480) and combine it with video1. Is there any way about it?