bigboss:
Gerrardasnails: Yes I do. Have you tried watching a DVD with your BD player set to 576i or whatever the native resolution is and then switching to 1080p?
Actually, it merely means that your blu-ray player is a better upscaler than your TV. When you set your BD player to 576i, your TV has to upscale the image, and when you switch to 1080p, your BD player upscales it.
This would still give the OP an example of upscaling, one by the screen and one by the BD player. You were right that he didn't understand what upscaling means.