i have a 1920 x 1080p TV. When i play the xbox on it, its at 1080p, when i watch a normal dvd on it with the xbox, its 580p.

 

If i have my laptop plugged in it's at the full 1920 x 1080 resolution, so if i watcha dvd through my laptop on the TV does it up-scale the picture????

 

Just that the picture looks better through the laptop, but could just be my brain??

Your assumption may possibly could be almost certainly might be correct about the laptop up scaling the image.

It all just depends on what decoder and chipset it's using.

I would have thought a DVD player, be it a stand alone or in a PC/laptop would play the disc at it's maximum quality anyway, but could be wrong.

i think it will upscale the image

yes, it will.