where is my upconversion coming from? let's solve a mystery

[liquidice]

so I bought Beetlejuice today, and when watching the cartoon contained on the disc, they were stretched to fill my whole display. "Odd", I thought to myself, then continued watching. When the first episode was over, I hit 'stop' which usually takes me to the PS3 screen confirming I want to end the disc playback. Curious thing is, that menu screen was also completely stretched out also! This is not how it normally looks when quitting a typical blu ray. Well, I proceeded to verify the resolution which is being detected as 480p, and that is true. I then flipped to my AVR to ensure conversion is 'off', which it was. I then even messed around with the HDMI video settings which I flipped to 'off', but then the AVR menu became all huge and dumb. I set it to 'on', and messed with choices while flipping back and forth with the video, and nothing changed at all. I even went to the video menu option of the PS3 and turned upconversion completely off, and still no change to the video or the 'quit' screen. So, what in the world is causing this automatic upconversion if it's not the AVR or the PS3?...or is it one of them and I'm missing a setting somewhere? If anyone has Beetlejuice, please check this yourself on any of the three cartoon contained on the main disc.