Ive used p tools off and on for sometime now. and i keep hearing about GOP i know it says the lower the number the less compression on it. Is this the only effecting compression? I also keep hearing the word Spanning Used alot with the gh2 on this site. can someone explain this too me.

Im trying to keep up with all these terms because im having problems with my camera as in when i hit record the video turns a weird green shift of colors. Ive seen some amazing videos from guys. i have a canon camera with Magic Lantern on it so I have hacked it and used its system. Ive used ptools so i know how to use it. but i feel some of you guys are doing something to the ptools or something. im not getting a good color.

is there some kind of link anyone knows of that can calabrate your gh2 screen to be right?