Wii: 480i actually a lower internal resolution than 480p?

[goatroper]

I've noticed that reviews/previews of the recently released Tenchu: Shadow Assasins for Wii mention that it runs in 16:9 widescreen, but only 480i resolution (regardless of aspect ratio).

This raises a simple question for me: does limiting to 480i output actually allow the developer to reduce the internal resolution at which the game is rendered?

My understanding was that 6th generation and above consoles would typically render to an internal resolution equal to or close to 480 pixels in height, prior to scaling and encoding into 480i or 480p, so games could basically do 480p "for free." Not so?

Doesn't the pixels to scanlines encoding "throw out" half the vertical resolution for games rendered at 480p/60 frames per second but displayed at 480i/60 fields per second? Please enlighten me.

 

[Endymion]

I'm pretty sure a lot of games render in the way that you describe, but if you think that the game in question must be rendering in fields instead then the above does not apply, right?

 

[Panajev2001a]

With interlaced displays you either render internally 640x480 at 30 fps and then display a field every 1/60th of a second (frame A, B, C, etc... : A's1st field, A's 2nd field, B's 1st field, etc...), or you render at 640x480 at 60 fps and someway (the CRTC or the GPU does it) you down-samplethe frame to a half-height field every 1/60th of a second, or you render directly in half-height buffers (the way some PS2 developers tried to do) losing some of the benefits of flicker-reducing filters.