#11 mp4box concatenating

[Basil]

Hi,
In my project I am using your great mp4box to concatenate two or more mp4 files into one.
My purpose is to get only one video track. However, as I understood, mp4box can concatenate mp4 files into one with one video track only under certain conditions - some video parameters between the combining files that have to match. I could encode some files if i detect diff in parameters. But i dont know what parameters to look for. i tried to google it, read the documentation, but did not find the exact list of those parameters that have to match. I even looked in source code, and found, where mp4box display error "No suitable destination track found - creating new one (type vide)" but I dont know any programm languages even php and bash.
Could you give me a full list of video parameters (audio parameters would be also helpful), which have to be identical between concatenating files?