Can someone tell me what's going on when I run these two commands. I am pulling a video off of my iPhone and then converting it to avi. The video is rotated so I rotate it with the second command.

My question is why is the file size shrinking after the rotation? I read through the documentation for the commands but nothing is jumping out at me. I'm guessing it has something to do with the codecs used with these commands. Any help or explanation would be helpful. Thanks.

Code:
ffmpeg -i chase_eating_noodles.mov -sameq -vcodec mpeg4 -acodec libmp3lame chase_eating_noodles.avi

mencoder -of avi -oac mp3lame -ovc lavc -vf rotate=1 -o chase_eating_noodles.avi cen.avi