[spiltrap]

I've recently started getting interested in building a home theatre based on a DLP projector. I've been looking at several different models and trying to learn as much as I can but can't seem to figure out what is really meant by HDTV support. At first I thought it had to do with the native resolution of the projector but I've found projectors with different resolutions that support HDTV. I thought that you needed 1080 lines to support HDTV yet there are 800x600 projectors that support HDTV. Can someone shed some light on exactly what is meant by HDTV support? It just doesn't seem to make much sense to me that an 800x600 projector can support it. Thanks

 

[Scott Gammans]

Basically, all that "HDTV support" means is that the projector can sync up with, accept and display an HDTV signal in whatever HDTV formats the projector supports (1080i, 720p, etc.) It does not mean that the projector can resolve every single pixel in the 1920 x 1080 matrix of a 1080i signal or the 1280 x 720 pixel grid of a 720p signal.


So, in a nutshell, if a projector is "HDTV compatible" it only means that it can accept an HDTV signal. It does not necessarily mean that it can display an HDTV signal at its full resolution.

 

[spiltrap]

Thanks for the quick reply. So is it safe to assume that if I'm using a HTPC to feed the video signal to a projector then any projector can be said to work with HDTV?

 

[Dean McManis]

Essentially, HDTV compliance with digital FPTVs comes down to the projector's internal scaler being able to input a HDTV signal and convert it to the FPTV's native resolution.


If you found a HTPC software or hardware product that could take in a HDTV signal and output at a projector's native resolution you could bypass the FPTV's internal scaler and display HD material on a non-HD compliant FPTV.


But generally those digital FPTVs that don't support HDTV input are lower resolution and don't do a great job with HDTV material compared to higher resolution models.


No consumer-priced FPTVs (digital or CRT) can fully resolve 1920 X 1080 resolution so far, but the higher the resolution capability of the display, the better it is likely to look.

Most XGA or better capable FPTVs will look quite good with a HD feed.


-Dean.

 

[William]

About two years ago CES or some other governing body came out with a set of rules for what could and could not be called HDTV compatable. This covered TV's, tuner boxes, and displays devives. Maybe someone could find and post the rules. I'm 98% positive in order for a display device to be called HDTV compatible it must fully resolve and display a minimum of 720x1280p. HDTV support on the other hand is almost meaningless. A HDTV signal goes in and something comes out. Support could mean to take a HDTV signal and downconvert it to a channel 3 RF signal played through a 12"B&W TV.

 

[Scott Gammans]

Quote:

Originally posted by spiltrap Thanks for the quick reply. So is it safe to assume that if I'm using a HTPC to feed the video signal to a projector then any projector can be said to work with HDTV?

No. If you are using an HTPC HDTV card like accessDTV or HiPix, you will still need to ensure that your projector can sync with an HDTV signal, since both of these cards send an actual HDTV signal to the projector when in full-screen mode (which I assume is what you would want, vs. watching HDTV in a desktop window).

 

[Dean McManis]

Scott,


I am unfamiliar with AccessDTV, but with the HiPix card (which I have) you can set the output resolution to XGA and it will downconvert the 1080i or 720p input to 1024 X 768 (576) resolution, so it should work OK even for XGA FPTVs without a HD compliant internal scaler. Although I haven't tested this out for sure because all of my displays are HD compliant.


-Dean.

 

[Scott Gammans]

Oops, my bad. The accessDTV card only outputs EDTV/HDTV signals (480p, 720p or 1080i) in full-screen mode from its own output VGA port on the card itself (in other words, in full-screen mode the HTPC's video card is bypassed altogether).