720p or 1080i OUTPUT to 1080p Set?

I've been hearing that some cable boxes don't have this pass through option. My friend recently purchased (past 2 days or so) a 50" plasma screen and a hd cable box. I was over watching and the HD was not that great. Seeing as the cable box was set to 1080i I figured there had to be a way to set it to 720p. I figured 720p would clear up the fuzziness and overly soft pictures. Navigating through the box I couldn't find the option to change the output resolution of the box but stumbled across the pass-through option behind a menu that I thought had nothing to do with video output. Needless to say the HD signal now looks like a true HD signal. I mean it looks worlds different. Bottom line: cable boxes suck when it comes to scaling to a particular resolution. If you are absolutely sure there is no pass-through, toss the box and get cable card if that is an option. If you are stuck with box scaling everything to one resolution or another, you probably are missing a potentially even better viewing experience. I will go back to her house tonight to see if I can get the model number and what menu option I found it under.

In the current poll trbarry is running in the hardware forum, there seems to be mixed results whether 1080p owners see differences between 720p or 1080i feeds on their 1080p displays.


As far back as I've read AVS, there are many posts--well before the 1080p era--from HD viewers saying 1080i appears sharper than 720p. Most earlier/current displays, of course, can't quite resolve the finest detail delivered via 1080i. And lots of 1080i programming, such as films, still falls short of 1080i's often-mentioned resolvable-detail 'maximum' (without oversampling/downconversion) of roughly 1450 lines.


Seems surprising, after these earlier typical results of 1080i/720p comparison, that 1080p display owners wouldn't continue noticing sharper HD images from 1080i sources. But, as always, there are lots of variables: As the recent C-NET 1080p shootout found, at least one 1080p DLP model (a Mits) only resolved ~1440 lines with a signal generator, presumably gradually blurring lines up to that point. And as Greg Merson's deinterlacing test showed, some 1080ps reduce vertical resolution too much with continuous 540p bobbing. Some displays lacking 1080i inverse telecine (24p frame extraction) wouldn't be showing film or 24p tape to best advantage. But it seems like bad news if displays that are finally capable of full 19020X1080 resolvable detail--never delivered, except for test patterns--have arrived and owners can't see 720p versus 1080i differences.


The often-reported contrasts between the two formats are live crowd scenes at sports events, or distant shots of players. In the past, most say 1080i delivers more detailed images, as you'd expect, primarily given the differences in the limiting resolution of the two main HD formats.


BTW, some 720p programming boosts this limiting resolution close to the full format (1280X720p) by downconverting 1080/24p master tapes (telecined films) or using newer TV cameras or systems that downconvert 1080/60p to 720/60p. That would narrow the perception gap of fine details between 720p and 1080i/p, although for some scenes such as distant live crowds, or fine scenic details (1080/60i travelogues or documentaries) captured with HDCAMs, 1080i/p, logically at least, should still have the sharper images. -- John