[bruno silva]"I've tried various programs but no one seem allow me to keep that frame size. HELP"
Please read the sticky at the top of this forum about getting the fastest help. If you can't take the time to explain what "various programs" are then there's very little direction anyone can offer. I can say "various programs" may work with proper settings but that wouldn't be very useful, would it?
Try Telestream Episode (my preferred) or Sorenson Squeeze.