HOWTO: YPrPb component output on any Radeon for under $5 - Page 4 - AVS Forum
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Old 01-17-2003, 10:56 AM
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I'm curious if your observation directly includes the Key Digtal VTCA-2 model w/ VGA passthru. I've compared it to the direct RGBHV inputs on my Mits HDTV and have found the image quality to be VERY close, with the transcoder seemingly having a tad less contrast, after checking several AVIA test patterns. Again, just curious!

Hi Wayne,
If you've got a Mits that can do RGBHV, why bother with component at all? Unless you're using a red-push attenuator I can see no advantage to transcoding to component. I got red of my red-push attenuator once performing the I2C hack to correct my color decoder, so I'm quite happy with RGBHV.
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Old 01-17-2003, 11:05 AM
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One (big) advantage: Interlaced video overlay support.

Maybe one "sub-advantage"... The Mits still has color, tint, and the YPrPb service menu functions working even when feeding it a RGBHV input, which suggests that it transcodes the RGB into YPrPb to process before turning it back into RGB to drive the CRT's. Feeding it "native" YPrPb might actually result in an improved image. I guess it would depend on who has better RGB to YPrPb conversion, ATI or Mitsubishi?

If I can trick my Radeon in XP into thinking it has the component dongle, I should be able to continue using the RGB lines of my RGBHV cable as YPrPb, and FINALLY get a chance to see my HTPC at 960i or 1080i.

I still firmly believe ATI should FIX INTERLACED OVERLAY without a dongle, I'm also very happy with the RGBHV connection after reducing red push via the service menu.
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Old 01-17-2003, 11:17 AM
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I'm with Helzerr - at a deep fundamental subconscious level, I NEED 1080i overlay!

I am for the moment stuck in XP and would really like to see this trick work for us!

Has anyone tried putting a scope on the pins of an actual ATI dongle to see what it's doing so the card detects it? pulling a pin low or high, or shorting two pins together? or is it more complicated than that?
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Old 01-17-2003, 11:34 AM
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Quote:


Originally posted by JKohn
Hi Wayne,
If you've got a Mits that can do RGBHV, why bother with component at all? Unless you're using a red-push attenuator I can see no advantage to transcoding to component. I got red of my red-push attenuator once performing the I2C hack to correct my color decoder, so I'm quite happy with RGBHV.

My Mits has only 1 DTV input and I have 3 HD component sources....Hughes HD Directv STB, HTPC and MyHD output. My Yamaha has 3 HD component inputs, so its a matter of source switching convenience, that's all.
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Old 01-17-2003, 11:39 AM
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I'm sure the dongles have one of these VESA eproms that the PC polls for the display info via a serial protocol.

ATI says they're out of stock of the DVI dongles, so I may have to investigate building one. I wasn't able to find much Free info on the VESA standards, and ATI may have ignored the standard for the dongles.
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Old 01-17-2003, 11:52 AM
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One (big) advantage: Interlaced video overlay support.

That's not an advantage of a transcoder. Note I wasn't talking about the dongle. And frankly the dongle is of no use to me if I can't output DVD's at 1080i.

Quote:


The Mits still has color, tint, and the YPrPb service menu functions working even when feeding it a RGBHV input, which suggests that it transcodes the RGB into YPrPb to process before turning it back into RGB to drive the CRT's. Feeding it "native" YPrPb might actually result in an improved image. I guess it would depend on who has better RGB to YPrPb conversion, ATI or Mitsubishi?

Again, this could possibly be an advantage of the dongle (let's just say I'm skeptical there would be any noticeable difference), but I seriously doubt an external transcoder would have this advantage.
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Old 01-17-2003, 12:34 PM
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you can output movies at 1080i with the dongle
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Old 01-17-2003, 01:16 PM
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Looks like one of these is all that's needed:

DDC serial eeprom. Digikey has them for $0.59.

and we just need someone to dump the contents of the dongle's eprom using something like this:

read-edid
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Old 01-17-2003, 02:36 PM
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If that's the answer, it looks a lot easier than trying to trick the computer into seeing a dongle in software; this way you can remove the "dongle" and have it go back to normal without playing in the registry.
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Old 01-17-2003, 03:11 PM
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Anyone running Linux who has a DVI and/or VGA dongle willing to run read-edid and post the results? I wonder if the contents of the edid eprom are copyrighted?
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Old 01-17-2003, 03:39 PM
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you can output movies at 1080i with the dongle

If it requires ripping the disc to the hard drive first, I'm not interested. Too much trouble, and totally destroys usebility. When I want to watch a DVD, I want to be able to put the disc in and press Play in TheaterTek. If it doesn't require ripping first, please PM me with more info.

Although hopefully we'll be able to get interlaced RGB with the popular players using VMR 9 in the not too distant future...
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Old 01-17-2003, 07:04 PM
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Viewsonic has a utility that claims to read the EDID data:

EDID Utility
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Old 01-17-2003, 07:30 PM
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to view movies at resolutions and timings other than 480p all you need is DVD Idle. Costs 19.95 to register and works perfectly
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Old 01-17-2003, 08:08 PM
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Ok, I got my DVI-A to component video cable today. The only way I can get proper component video out is to hot swap the ATI HDTV component adapter out. Booting up with the DVI-A cable won't work. Tried adding the rule HDTVRULE_HDTVCONNECTED = 1 to 70 or so locations in the registry. That did'nt work for me either.

Slightly better picture quality with much less bulky cables. Hope somebody finds a solution for this case.

I'm running Windows XP and my video card is a ATI AIW 8500DV.
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Old 01-17-2003, 09:16 PM
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MadCat-

A software way to do it would be to write some code that Intercepts the EDID API in WinXP and return the appropriate data to the ATI drivers. I don't know if this is possible, but it might be.

This looks promising: Reading EDID
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Old 01-17-2003, 10:12 PM
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to view movies at resolutions and timings other than 480p all you need is DVD Idle. Costs 19.95 to register and works perfectly

In that case I'm definitely interested in getting 1440x960i working; hopefully somebody can figure out how to do this under XP.
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Old 01-17-2003, 11:30 PM
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So what IS the difference between a transcoder and this (or any like it) dongle?

Couldn't I just use this dongle with my Nvidia card, and use some custom timings from powerstrip?

Transcoders seem really expensive.
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Old 01-18-2003, 12:15 AM
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The difference is, ATI Radeon cards are apparently capable of internally rendering a screen directly to YPrPb output, or at least have transcoder circuitry built into them which is ideally matched to the VGA output it generates. This means all you need is a dongle that "tells" the card to output in YPrPb instead of RGB, and the same dongle replaces a VGA connector with a component connector. This -should- create a slightly better picture than outputting VGA into a cable, into a transcoder box that has a bunch of circuitry external to the video card, and then out to the TV. It's also a LOT cheaper since you already have the circuitry to do it on your card.
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Old 01-18-2003, 03:55 AM
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Quote:


Originally posted by 0db
I'm with Helzerr - at a deep fundamental subconscious level, I NEED 1080i overlay!

I'm surprised that so many people here are interested in interlaced resolutions. In a forum which is devoted to the best image quality, I'd think more people would be bothered by the inferiority of interlaced display. Personally I think interlaced looks like absolute crap, and you're better off just running in 540p or 480p. It's not like you can get something from nothing anyway, and all DVDs run at only 720*480p.
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Old 01-18-2003, 07:46 AM - Thread Starter
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Originally posted by jxm71
Does this mean if I already have a DVI to Component cable, all I need to do is add the "HDTVRULE_..." key to my registry and it wil work?

yeap. If you got Win9x that is. I dual boot when i just need that HDTV goodness
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Old 01-18-2003, 07:55 AM - Thread Starter
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Originally posted by BigggWilly
So what IS the difference between a transcoder and this (or any like it) dongle?

Couldn't I just use this dongle with my Nvidia card, and use some custom timings from powerstrip?

Transcoders seem really expensive.

Ok, couple things:



1) The dongle is quite different from a transcoder. A transcoder does exactly that - translates a code into a different code. In this instance, the VGA->YPbPr transcoder takes the VGA signal and interprets it into a signal that the TV can read. This what makes them so expensive --- they CHANGE the signal. The ATI dongle or those $20 VGA->RCA cables have no transcoding circuitry; the signal they output is the exact same one being input.

2) The dongles are specifically built to interface with ATI hardware, and none other (why you'd want to anyway is beyond me).

3) There are no dongles "like" it, because this is a genius idea (from a business perspective) from ATI alone. They can sell these $30 adapters that do absolutely nothing but tell your drivers to do something they can already do, then add $15 minimum shipping, and make a ton of money doing it. They probably cost in the range of about $0.50 each to produce. The cable adapters you see that might resemble these are just adapters, and always remember, if you see a price tag that's too good to be true, it probably is.

hope this helps. -deth
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Old 01-18-2003, 07:57 AM - Thread Starter
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Originally posted by JamesL
Viewsonic has a utility that claims to read the EDID data:

EDID Utility

sweet

nice lookin out. -deth
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Old 01-18-2003, 07:57 AM
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DVD can not be viewed at any other resolution than standard res like 480p or 480p in 540p timing, or 1776x1000i and 1080i thanks to ATI having virtual desktop enabled I widh I could find a way to disable virtual desktop.

What'll happen is you will get the top 1/4 of the video and it'll be zoomed in sort of to fill the overlay screen


==================================================
I'm surprised that so many people here are interested in interlaced resolutions. In a forum which is devoted to the best image quality, I'd think more people would be bothered by the inferiority of interlaced display. Personally I think interlaced looks like absolute crap, and you're better off just running in 540p or 480p. It's not like you can get something from nothing anyway, and all DVDs run at only 720*480p.
====================================================

I can tell you have never seen a good 1080i signal I thought the same thing but once you see it you'll see why

I even like to run my games at 960i since it is a higher (and interlaced) res the images on screen appear much sharper than at 480p or 540p resolutions, much more contrast as well
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Old 01-18-2003, 08:02 AM - Thread Starter
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Quote:


Originally posted by MadCat
Ok, I got my DVI-A to component video cable today. The only way I can get proper component video out is to hot swap the ATI HDTV component adapter out. Booting up with the DVI-A cable won't work. Tried adding the rule HDTVRULE_HDTVCONNECTED = 1 to 70 or so locations in the registry. That did'nt work for me either.

Slightly better picture quality with much less bulky cables. Hope somebody finds a solution for this case.

I'm running Windows XP and my video card is a ATI AIW 8500DV.

please read the disclaimer in the original howto. This mod is for Win9x only, because we don't have the keys to force it in XP yet. However, hot swapping in XP works? Now that's interesting. What if we had a piece of software fake the DDC info from the dongle (a tsr could do this) and send it to the drivers? I think we're getting close. Keep the tests coming!
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Old 01-18-2003, 08:23 AM - Thread Starter
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Quote:


Originally posted by JamesL
Anyone running Linux who has a DVI and/or VGA dongle willing to run read-edid and post the results? I wonder if the contents of the edid eprom are copyrighted?

you don't need linux. Look at the bottom of the webpage, there's a dos binary -- which i just tried -- that works.

Ok, i think i've got another idea. I really, REALLY like the idea of programming our own EDID eprom. If it's something as simple as sending an EDID signal back through a couple pins on the VGA port, i'm more than willing to build it. Being that i already trashed my dongle dissecting it (it didnt quite fit together afterwards, hmmm) someone else would have to dump the EDID for us. Which is actually quite easy. If anyone here owns a dongle and is interested (all it involves is running one program to grab the EDID and another to parse it, then forwarding me the results), please email me: dethnite@subdimension.com

-deth

i could build one of these in two days. Dayem, im getting excited!
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Old 01-18-2003, 08:26 AM - Thread Starter
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Originally posted by JamesL
Viewsonic has a utility that claims to read the EDID data:

EDID Utility

it won't work, because it doesn't support DDC2 correctly. Doesnt even find a monitor on my setup

but that command-line program, get-edid, is really sweet. It can even pipe the EDID to a parser or file for easy sharing.
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Old 01-18-2003, 09:24 AM
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Originally posted by dethnite
Last, download powerstrip (http://www.entechtaiwan.com/ps.htm), load it up, go to Color profiles -> Configure, then uncheck "Write directly to palette DAC" and "Enable color correction".

You only need to do that if you are using an old, pre-dongle version of PowerStrip.
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Old 01-18-2003, 09:48 AM
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too bad no one can figure out how to add certain interlaced resolutions without powerstrip disableing tile based rendering.... I can do it but once I do most of my custom interlaced resolutions do not work (any that have virtual desktop kick in)

1776x1000i and 1920x1080i are able to be displayed but 1280x960i and other resolutions in other timings (1280x1024 in 1080i, 1024x768 in 1080i etc) when tile based rendering is enabled

so I either have comaptibility with more resolutions and have tile based rendering disbaled or less resolutions availible and tile based rendering is on.......

For now most games are playable at 1280x960i but not quite as high FPS I cant run AA or aniso at all because of the stupid tile based rendering thing

I can run games at 720x480 and 640x480 in a 540p timing with 4xaa and 16x aniso but doesnt look any where near as crisp as 1280x960i does

Most games will not take 1776x1000i as a resolution to play in
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Old 01-18-2003, 10:14 AM
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please read the disclaimer in the original howto. This mod is for Win9x only, because we don't have the keys to force it in XP yet.

I saw the disclaimer. I wanted to play too. I'll be loading Windows 98 to see if I can get it to work from there for a baseline.
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Old 01-18-2003, 10:54 PM
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I hate doing this but -bump- don't want this thread to disappear - looks like a hot weekend on AVSforum and can't let this slip through the cracks!
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