480 input message with blue ray dvds

[elendilmir]

I have a SOny s350 player, which is wonderful. However, when I select the recall function, which pulls what I think is the input characteristics like input aspect and resolution, it shows 480 even when I have blu ray disks inserted. Do I need to activate the Blu Ray resolution, or are my disks just mastered in 480 and put out on blue ray disks? The display isn't static, as the aspect will change from 4:3 to 16:9.

Thanks for your help.