HDTV Forum

i currently have the samsung hl-t5676s 56" dlp and directv....i also have the the samsung ht-tx72 surround system.... my questions...

does directv 's hd reciever output in 1080i format? and if so does my tv convert it to 1080p for the best picture?

with the 5.1 surround it says it will upconvert a standard dvd to 1080i , and then the tv will convert to 1080p..is this correct?

and last my tv's specs says it will input 480i/p 720p and 1080i/p, does it automatically unconvert any of these formats to 1080p viewing....so basically anything i input to the tv will automatically convert to 1080p??? thanks

Since your TV is a microdisplay, it is only capable of displaying a 1080p picture regardless of the input. We'll ignore the debate on whether it's really 1080p if it uses a 920x1080 array that does half of the picture at a time.

Yes, your DirecTV receiver can output a 1080i signal and in this case that would be preferable.

Your TV will convert the 1080i signal to 1080p before it is displayed.
It will also convert a 480i/p or 720p signal to 1080p. It has to because it can only display 1080p.

CRTs had the ability to change their scan rates. Fixed pixel displays don't. So you get 1080p no matter what you feed it. The only question is whether to scale the image to 1080i/p before sending it to the TV. Generally speaking the scalers outside the TV are better than the one in the TV so you should try to scale it to at least 1080i first. But that's a guideline, not a rule and you might find that the TV scaler works better. Just try it and see.

ok so what your saying is its better to send the directv 1080i straight to the tv rather than sending it 480 to a reciever and then upconverting it to the tv??

and your also saying that its better to upconvert a dvd to 1080i then sending it to the tv rather than sending the dvd through a non upconverting player and letting the tv do the upconversion??

so my tv will display 1080p, and 1080p only?? is this tv a good choice for veiwing HD hinting that you say it uses 920x1080..is this a different picture than 1920x1080...

thanks again for your help

Basically - Yes to all your questions. If you have the option of letting the TV do the upconversion I'd try it both ways. Some of the newer TVs may scale better than some of the older video sources and it will vary by manufacturer. Just try it both ways and see which one looks better. Sometimes the TV takes a few seconds to change the input scan rate so take that into account if you're changing sources a lot.

I should have said 960x1080 on the actual DLP chip. I don't know if TI has come out with a chip that contains 1920x1080 mirrors but I assume they're still using wobulation to get the full display resolution from a 960x1080 chip with wobulation.

The way it works is similar to how interlacing worked on CRTs. Each mirror represents a pixel and that mirror is either on or off (reflects light or doesn't). Half of the 1080p pixels (960x1080) are displayed first, then the entire assembly is shifted over and the other half of the 1080p pixels get displayed 1/120th of a second later. So you get the entire picture every 1/60th of a second. As opposed to having a single chip with 1920x1080 pixels and displaying all of them at once. This technique is called wobulation. Some claim to see a difference between 720p chips with and without wobulation.

wow you couldnt have said it any better thanks again for your help!!

Wobulation is a less expensive way to provide 1080p rear projection displays and yes there is a difference between wobulated 1080p and real 1080p which is with real 1080p you can actually see the pixels if you are close enough to the screen. Full pixel matrix 1920X1080 DMD chips are used for front projection. Wobulation does cause a softening of picture detail when directly compared to a full matrix.

A great SD DVD player for your display is the OPPO DV-981HD Upconverting SD DVD Player

on the samsung tv mentioned above (hl-t5676s) will it still upconvert to 1080p if using a standard def dvd player with rca's or components or will it only upconvert via hdmi?

Read Akirby's post ....

if it is not 1080p from the source the TV HAS TO convert/scale that source to 1080p or you won't be able to view it.

The Oppo will definitely do a better job scaling to 1080p than your TV... Try out your current DVD player, recommend you set it for 480p, and if you are satisfied then you are done.

ok i wasnt sure...i understand that my tv only displays 1080p but i couldnt see how i would get that quality from an older dvd player through rca's compared to hdmi...

Quality is a different story. What Richard meant was your tv only knows how to display 1920x1080 pixels. Anything less gets upconverted. Your 480p dvd output will not look as good as a HD DVD or Blu-Ray 1080p. It can't. It's like taking a 4x6 picture and blowing it up to 8.5x11.

Concentrate on getting the best picture into your TV and you'll see the best picture quality.