[Big Jeff]

The RPTV I was considering can only do 480p or 1080i. It's the 55 phillips at Best Buy. We I be wishing it could do 720p ? I plan on getting OTA HD.

 

[John Mason]

Welcome to the forums. Those who can display true 720p (not many) say it appears somewhat better than 720p sideconverted to 1080i (most setups). My Philips RPTV and my HD cable converter does this sideconversion and 720p/1080i looks fine. The 480p feature, also built into my 28-month-old set, could be an advantage, since from numerous posts here it appears some newer models that upscale 480i to higher resolutions (540, 960, etc.) worsen image quality. -- John

 

[Big Jeff]

Do most HD tuners/Decoders with convert 720p to 1080i ?

I noticed some OTA channels are broadcast in 720p.

Thanks

 

[John Mason]

They all can perform a 720p-to-1080i sideconversion. And if you're buying a 720p-capable HDTV-ready set, you should check whether the tuner you acquire can be switched to a native 720p output (not sideconverted). -- John

 

[jeffmcclan]

Some RPTVs display 720p natively (ie. DLP sets) and others display 1080i natively. I don't believe there a limited number of sets that display both resolutions (without conversion to the other resolution).


Given that someOTA HD stations broadcast in 720P (ie. ABC) while others broadcast in 1080i (ie. CBS), the HD tuner or STB sideconverts the resolution so viewers can watch all channels.

 

[tbdombrosky]

I thought nothing was capable of native 1080i yet. Do you mean 1080i converted to 540p?


Tom

 

[CupertinoSlim]

Big Jeff, this question comes up in various ways on a fairly regular basis.


Sets have inputs, of course, and output, which is the screen. In RPTVs, the arrangement of pixels for the screen is not identical to standard HDTV inputs, so images need to be mapped to the different screen layout so the images have the proper aspect ratio. The screen might be 1364 x 738, for example, on a good set. It's not exactly 720, so the image is redistributed across the pixels.


"Upconverting" means that the input signal is converted to a standard one that has more pixels before being mapped to the screen. If the signal is non-HDTV, such as 480p or 480i, some take it to 720, some to 540, before mapping it. They all can map 1080 down to their screen layout.


All that said, is it inherently better to upconvert to 540 or 720? Since you're starting with the same information from the input, it might not make much difference. Many of us assume that upconverting to 720 implies that the processing is more sophisticated or that the screen has a greater number of pixels. It certainly sounds better to talk about it. Is it really better to upconvert to 720, which the set has to be able to map from? Or is it better to have a mapping algorighm specifically for some intermediate level or even for 480 directly?


Either could be better.