[John Haghighi]

Can someone explain if using a DVI DVD player with a RPTV will make a noticeable difference in PQ? From what I have read, it seems that the pure digital connection benefits DLP displays more than RPTV's as there is a stage of digital to analog conversion here.


So what's the point in spending the extra money to get a DVI capable player if you have a good Progressive Scan player already?

 

[steviec]

I believe you may be right.they work best with plasma because their black level is not as good as crt displays.The dvi connection does not show all the info below black,hence you will get better rez using component on a rptv.

 

[Ragermac]

Many people have posted improvements using DVI connections on their RPTVs. Do a search on the subject and you will see. Alot depends on your TV. The Hitachi's have been shown to benefit from the DVI input.

 

[tboo]

Quote:

Originally posted by Ragermac . The Hitachi's have been shown to benefit from the DVI input.

I concur. before I got my 50 Panny LCD RPTV. I had a Hitachi 51swx20b & the picture was better using my Samsung 931(upconverted to 1080i) via DVI than with my old Denon 2900 & component cables

 

[scarey1999]

steviec almost hit the nail on the head. I know I am a noob on this forum, but I have been researching this topic for a while now. The consensus seems to be that using the DVI out from a DVD player to a plasma screen will give you better results since it can replicate pixel for pixel due to the true full digital nature of the connection. While DVI out from a DVD player to a RPTV will not give you the same level of improvement as you would see on a plasma screen, you will still see marked improvement in picture quality since you are not losing information by converting digital to analog with DVI as you do with component out. Hope that helps!

 

[Babula]

RPTV using Cathode Ray Tubes (CRT) is analog technology. The electron guns of the CRTs "paint" the phosphorescent screen line by line and no real control over individual pixels. I don't believe DVI would present a better picture as the final CRT display is controlled by the physics of the CRT system design. I would think that all one is doing by feeding DVI to the display processing circuitry of the RPTV is adding a conversion process that does not mean anything. Analog to Digital to Analog.


LCD and Plasma devices controll their pixels, pixel by pixel, not scanning line by scanning line.

 

[mnilan]

John:

Read the review of the Bravo D1 DVD player in this month's Widescreen Review. It has a cogent discussion of DVI and what benefits are possible with which types of displays.

 

[scarey1999]

Quote:

Originally posted by Babula I would think that all one is doing by feeding DVI to the display processing circuitry of the RPTV is adding a conversion process that does not mean anything. Analog to Digital to Analog.

I had read in threads elsewhere that the conversion is a problem and lead to worse pq due to information loss/degredation. DVI does not have these conversions and thus you are able to attain better pq. Is this information incorrect?

 

[zxe018]

I am no expert, but from research I believe by using DVI, you are bypassing the internal scalar of the RPTV. You will see improvement if the scalar in the DVD player is much better than the one in the TV. Plus, having the deinterlacing and scaling all in the digital domain also helps.

 

[DiamondDave]

Chris is correct. The biggest benefit with the DVI connection is on sets like the Samsung DLPs, where the native resolution is 720p. When you set the 931 to 720p as well, there is no signal conversion from the player to the screen. For me, the difference was huge. For RPTVs, it seems to vary depending on the TV.

 

[mnilan]

Folks:

Just a semantic point here. Digital Light Processing or DLP is a technology that has been implemented in front projection systems and in rear projection TV systems (i.e., RPTV). Most of the content in the RPTV area is referring to DLP RPTVs.

 

[Darin]

Quote:

Originally posted by Babula RPTV using Cathode Ray Tubes (CRT) is analog technology. I would think that all one is doing by feeding DVI to the display processing circuitry of the RPTV is adding a conversion process that does not mean anything. Analog to Digital to Analog.

There are a couple of important steps you are forgetting. A: the video starts out in the DVD player as digital. B: Many HD sets convert an analog standard def signal into digital to do upscaling and other "enhancments".


So in the case of a CRT set, who's output is analog in nature, your "analog to digital to analog" is really either:


"standard" DVD player: digital to analog to digital to analog


DVI output player: digital to analog.


IF the TV does no digital conversion, then in both cases, it's: digital to analog. The only difference is WHERE that conversion takes place... in the DVD player, or in the TV.

 

[sjyang]

John:


I've read the thread. An RPTV can incorporate at minimum four display technologies: CRT, DLP, LCD or LCoS (with more on the way). The DLP, LCD and LCoS (whether an RPTV or Front Projector) are all fixed pixel technologies and can really benefit from the signal staying digital until it actually hits the "display chip".


I have a Samsung DLP RPTV and it looks particularly crisp when going through DVI.


Not having looked at CRT based RPTVs or Front View CRTs with DVI, I can't really comment. Though some on the forum have tried it to mediocre results.

 

[Joe Murphy Jr]

>>>The dvi connection does not show all the info below black

 

[sspears]

Quote:

Whether information "below black" is shown is a manufacturer's choice

And not showing it means the product is out of spec and not worth owning, it should be dumped in the trashcan because it will not produce correct video, period end of story!


CCIR 601 defines luma from 1 to 254 with nominal black at 16 and white at 235. If you do not get 1 to 254, then you are not getting the full 8-bits of video, you are getting something closer to 7.5-bits.

Quote:

The dvi connection does not show all the info below black

When properly implemented it does.

 

[Joe Murphy Jr]

Quote:

Originally posted by Joe Murphy Jr At this point in time, I think any DVD player that can't pass PLUGE on every output should be recalled.

Don't trash 'em, make 'em do it right!


Unfortunately, passing PLUGE is not a mandatory spec for DVD players. Obviously, neither videophiles nor audiophiles were consulted when issues of picture and sound quality arose on the DVD drawing board.

:-(

 

[pnichols]

........... and even if your DVI transmission format is putting out bits 0 to 15 off the DVD .......... what is your fixed pixel display doing with them, if anything?


Are they ANY fix pix displays (outside of TI's 3-chip $6-figure theater DLP projectors) available yet for HT that are not leaky enough to in fact show any dark detail using those bottom bits?


I'd like to see a spec on fixed pixel displays showing their light output resolving capability on bits below some criteria threshold - say perhaps below bit 20. The fix pix adds/specs I see so far seem to talk about their CR, but don't mention how leaky they are in the low end.

 

[Joe Murphy Jr]

Now, Phil, you know damn well that while DLP sets don't display blacks very well, they do a wonderful job of displaying red, green, blue, indigo and violet. Hey, aren't those the colors in a...

 

[pnichols]

Joe,


If I can afford it, I'll buy the 1st DLP projector that can deal with that doggone black garage scene from "Space Cowboys"........ IMHO the reference black scene in a movie. It took me several days of tweaking to get my analog setup to deal with that baby!


(I will admit that there isn't any indigo or violet in that scene though.)

 

[John Haghighi]

So basically don't waste my money on the DVD DVI player for a CRT based RPTV. I suppose the same applies with and HD STB w/DVI..currently I'm using the DTC-100..