Quote:
Originally Posted by
tripod39 
Never had a 720 set (D450) before,always 1080.Should I reset my cable box output to 720p or leave it at 1080i.Will run BR today to compare to 1080.
Despite being marketed as '720p',
neither the 51" nor 43" versions of the D450/D490 match the broadcast standard of 1280x720p.
The best setting,
if one's DVR has it, and it works properly, is 'native passthrough'; that let's the DVR send any given channel's native broadcast signal to your TV, and lets the TV scale it to it's resolution.
Sometimes, there can only be one DVR resolution setting (or that's all that works properly), and then you must decide on one, of course.
The 51" versions are 1360x768p; that is more resolution than 1280x720p. A 1280x720p setting (on the cable box) would cause 1920x1080i to be downscaled to less than the TV's native res., and then upscale it; that's not good.
So, if you can only choose one setting, it should be 1920x1080i, IMO. (I've had a 50" 1366x768p TV for 8.25 years.)
The 43" versions are 1024x768p; that is less resolution than 1280x720p; (less horizontal resolution, but more vertical resolution). For the latter reason, a 1280x720p setting would still downscale the vertical res. to less than the TV's native vertical res., and then upscale it; again, not good.
So, I would choose the 1920x1080i setting for this TV, also.
Rule of thumb, (that I and some others have noticed), is that
it's worse to downscale the signal to less than TV's native res. (vert. and/or horiz.), and then upscale it to the TV's native res., because the removed resolution can't be recaptured in upscaling. It is better to upscale the signal, and then downscale to the TV's native res.
I tried to make that as easy as possible, but it does get a little technical. Basically, my eyes have agreed with the science of it.

YMMV