I converted one of my movies that was an Avi format to a MPG format so i can burn into a vcd later. bUt when i converted i noticed the size of the screen is smaller

i used TMpgEnc and i followed all step
i used 1:1 VGA for source aspect ratio
and also i used full screen keep aspect ratio
and i tried both highest and high quality

can someone tell me when i put it on vcd will it be as clear as the avi? i mean its smaller.. so its gotta be worse resolution when brought to a full screen right?
limme know thanks u guys!