How to join two video frames into one, so the final video plays two frames as one simultenously

Question

I want to connect two videos into one. Let's take two videos from Youtube as an example. I want my final video to have the height = height of first video + height of second video and width = max(width of first video, width of second video). In the upper part the first video is played whereas in the lower part the second video is played.

Do you know how to do it under Linux, the best possibility while using mencoder, ffmpeg or any other command line command?

Answer 1

I think I found the answer here: http://stackoverflow.com/questions/575705/how-can-i-tile-videos-create-a-video-montage I will have a closer look into the solutions posted in that thread.