Do TVs always have to scale material (CRT vs LCD)?


I'm trying to better understand the scaling/processing that goes on at the TV level for resolution stuff (e.g., displaying 480i on a CRT versus display on an LCD with a native resolution of 1080p). Say I have a CRT TV that says in the manual that it can display 480i, 480p, 720p, and 1080i. When I tell Roku to output 720p to the CRT, is scaling going on? If so, who is doing the scaling, Roku or the CRT?

 

Does displaying the image on an LCD change this in anyway? CRTs don't have a "native resolution" the same way that LCDs do. So if the native res of an LCD is 1080p, does the LCD have to do scaling of 720p material that the CRT does not before displaying it?

 

What about a DVD player? Since DVD is native 480i, if I wanted to avoid any processing I could set the player to output to the TV at 480i. Does the CRT have to scale/process this 480i image in any way before display? My understanding is that LCD can only display progressively, so the LCD would have to process the material from 480i to 480p (at a minimum) if the DVD Player hasn't already done it. But does the LCD also have to process the 480 to whatever its native resolution is (e.g., 1080), something the CRT does not have to do?