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Discussion Starter · #1 ·
I wanted to share my not-so-little adventure in attempting to split DVI signal to a flat panel display (FPD) and a HDTV. I don't pretend to be

any kind of expert, I'm just some guy who spent a bunch of time and research on this and hoped what i learned might be of use to someone else.


Goal

^^^^

Simultaneously output DVI video to FPD and a HDTV


Issues

^^^^^^

* The HDTV is located across the room from the computer, about 35-40 feet

away.

* Output 3-d screensaver and winamp visualizations to HDTV



Pieces (see below for results)

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

* Dell Dimension 8200 running WinXP, 256MB RAM


* Dell 17' FPD


* Panasonic Tau ct-34wx50 HDTV (1080i compatable)
http://www.panasonic.com/consumer_el...v/tau_hdtv.asp


* ATI AIW 8500dv
http://www.ati.com/products/pc/aiwra...0dv/index.html


* ATI DVI-I --> HDTV component adapter
http://www.ati.com/products/pc/hdtvadapter/index.html


* Gefen DVI splitter box http://www.gefen.com/kvm/product.jsp?prod_id=1403


* Pacific Custom Cable DVI Digital Male to 2 DVI Digital Female Splitter

Cable (Returned)
http://www.pacificcable.com/Picture_...ataName=DVIY-2


* Pacific Custom Cable DVI-I F/F Gender Changer
http://www.pacificcable.com/Picture_...ataName=DVIIFF


* Pacific Custom Cable DVI-D Extender 66 ft. DVI Digital to multimode

fiber
http://www.pacificcable.com/Picture_...aName=DDI-A020


* Monster Y-Pr-Pb cable


* A couple 6' DVI cables (one came with the Dell for it's FPD; the other

came with the Gefen DVI splitter box)


The Story

^^^^^^^^^

I thought this project would be pretty straightforward at first, but

quickly found otherwise. Because DVI is so new, many vendors still don't

have much expertise with it, and when I would call tech support for the

various equipment producers, they inevitably wouldn't know anything about

compatibility issues between their product and others. So, i decided to

just start buying a configuration I though had the best chance of

succeeding, while minimizing the amount of work I would have to do.


The Card

^^^^^^^^

One of the first things i had to decide was weather or not to stick with

my current graphics card, an ATI AIW 8500dv with but one display output.

My preliminary research indicated that I might have an easier time of it if

I used a dual-output card such as the Matrox Millennium G550 Dual-DVI

(which won't work for me because I need good 3d performance), or something

like the ATI Radon 9700 which has both DVI and VGA but is very expensive.

In the end i decided to stick with the 8500dv and try and split the

signal.


DVI splitter cable

^^^^^^^^^^^^^^^^^^

The first thing i tried was PCC's DVI splitter cable (see PARTS section

above). It was relatively cheap and easy, if it would only work. No one

could really tell me if it would. So when it came with the rest of the

equipment i ordered from PCC, I plugged the male end into the 8500dv, and

the DVI cable into one of the female ends... but no dice. The monitor

was getting some kind of signal, but no display. So i returned it and

bought the active DVI Gefen splitter box.


The DVI Splitter Box

^^^^^^^^^^^^^^^^^^^^

At $299 it wasn't cheap, but I knew it would work, and also liked the fact

that it's a splitter and signal booster at the same time. Sure enough

when it came, it worked like a charm, outputting display to the FPD from

both output ports.


All for naught

^^^^^^^^^^^^^^

My minor success above was met with major defeat when I connected the

rest of the equipment up like so:
Code:
Gefen

Computer--Splitter-->FPD

||

\\/

66' M-M F-F ATI Component

Optical -->Adapter --> Adapter --> HDTV

The FPD was working fine, but the HDTV wasn't getting any signal at all.

Perhaps it was the optical cable? I hooked the computer the the optical to

the FPD, and everything was fine. AFter some more useless dorking, I

decided to cut out everything I could to troubleshoot, and set up the

following by moving the computer across the room:


Computer-->DVI --> F-F -->ATI Component-->HDTV

Cable Adapter Adapter


Failure. No signal. Damnit, what now? I then realized that I could (and

should) simplify even more, and removed the DVI cable and the F-F Adapter

from the equation, resulting in:



Computer-->ATI Component-->HDTV

Adapter


Success!! I was getting a virtual desktop and some overscan issues, but

both of those were expected issues i could deal with later. And the

picture was indeed beautiful.


At this point I thought I'd identified the problem as either a bad DVI

cable, or a bad F-F DVI adapter. To test, I hooked up both DVI M-M dvi

cables to the F-F adapter, resulting in a 13' DVI cable. Plugged on end

into the computer, and the other into the FPD and... Damn, there's

perfect display! I was expecting no signal... What the?!


I need some help at this point, so I decided to call David at PCC, who has

been pretty helpful in the past. They have a great DVI tutorial on their

site and really know what they're talking about. I call and get David

almost immediately (what? no 30min hold??), and explain the situation to

him. After about 5 minutes, he asks me to look at the DVI cable I'm using,

"what's it look like? Does it have the 4 pins around the blade?


"Nope, just the blade"


"So it's a DVI-D cable, right"


"Yes that's right, single-link DVI-D"


"Well that's your problem. That's a digital only cable, it will only pass

digital signal. Your adapter probably needs analogue signal"


Ah crap! I immediately know he's right and feel like a dummy. This throws

a serious monkeywrench into my plans as the 66' optical cable that i need

to get across the room is also DVI-D, and they don't sell it with DVI-I.

So it's useless to me. And the DVI spec sez that copper DVI can not go

further then 15 feet.


Alternate solutions

^^^^^^^^^^^^^^^^^^^

I guess at this point I can think about getting a dual display card and

run a long VGA cable across the room, but i'm worried about ground-loop

interference problems that I know exist in this building (I need to run

the final cable under the floor, and it will take at least 45' this way).


Conclusion

^^^^^^^^^^

Go out and have a drink. Think about it tomorrow.
 

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Discussion Starter · #2 ·
Hi I"m a big dumb newbie!! grrrrrrr


It's just not my day. I didn't intend to post this yet, i accidently hit the "post" button by mistake.... i just wanted to preview it first. boo hoo. my ascii diagrams are all screwed up and I see you can't add html into posts.


oh well. now it's *really* time to go have a few drinks.
 

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I was running about 50 feet of SVGA cable from my 8500 without problem. I'm currently using a SVGA hub that I bought for $10 on ebay, but only because I'm splitting the signal between 2 displays. Don't worry about cable length until you've had a chance to experiment.


By the way, you can edit posts and redeem yourself!
 

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Thanks for the good information, this will be very helpful to a number of us who would like to find a way to drive a HDTV and LCD display from a 8500DV or other single DVI based card.
 

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I may not completely understand what you are doing.


Are you using the ATI HDTV adapter to convert form DVI to Component?


I thought that once you boot to Windows and the OS recognizes that the adapter (doggle) is attached, you loose the DVI output. Wouldn't this hamper your ability to split the DVI signal?
 

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Per wienerdog,


I think you may have trouble getting the DVI port to drive both an RGB (FPD) and YPrBr (HDTV) display simultaneously with this setup. For this to work, I suspect ATI's DVI-I-to-component adapter would need to passively convert RGB to YPbPr. Unfortunately, I think it needs a little help from the Catalyst drivers to get the YPbPr rolling.


Maybe with Powerstrip, but I have my doubts. I'll be curious to see your results though. Cuz maybe I'm wrong about all this.


If you simply want to switch between the two displays, that may be more doable.
 

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My interpretation is that you want to directly drive the HDTV and the LCD (although probably a CRT would work better directly from the DVI. He is using the DVI splitter box to get clean amplified DVI signals, and would probably set the ATI resolution (or using scaler) to the native HTDV resolution.


The one problem I see is that the resolutions would have to match, and we all know that LCD screens usually look very bad when not matched to their native resolution. Since we also want the native (and possibly uncompatible) resolution of the HDTV, this may not be a very workable solution (and a $299 DVI splitter box kind of defeats any cost saving over a new video card).


Perhaps a dual DVI graphics would be the better way to go, or using an analog driver for one of the outputs and using the more readily available dual monitor capable ATI cards. Unfortunately I believe all ATI cards are either dual monitor or AIW and not both. I would believe that within the next 12 months we will start to see video card makers providing this kind of support directly, probably providing a component video and DVI with a HDTV AIW single card solution.
 

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The component dongle definitely does NOT convert RGB to YPrPb component. It simply tells the ATI card: "HEY I'M A COMPONENT ADAPTER" and the card switches internally to rendering YPrPb, which would of course make your other DVI or VGA output worthless. If you don't believe it, try hooking up the HDTV dongle to the DVI port, boot the computer, and then plug a monitor into the VGA port or hot-swap another monitor into the DVI port. The colors will be very wrong.
 

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Quote:
Unfortunately I believe all ATI cards are either dual monitor or AIW and not both.
I spent a bunch of time researching this a few months ago and I believe my conclusion (per information on the ATI website) was that this is true for all of the ATI cards except the ATI AIW 9700 Pro. I believe it has the ability (with a dongle) to support component output to one screen and analog output to an LCD monitor simultaneously. I had wanted to use the LCD monitor for PC UI stuff and the component outputs would be used to display video files only.


I never got deeper into this because the $400+ price of the card at the time made me decide to put off my dreams until this card came down in price some more.


If anyone else actually set this up I'd be interested in hearing about it.


Doug
 

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Discussion Starter · #12 ·

Originally posted by wienerdog



Are you using the ATI HDTV adapter to convert form DVI to Component?


Yes. That's all you *can* do with it. See it's URL on the parts list.


I thought that once you boot to Windows and the OS recognizes that the adapter (doggle) is attached, you loose the DVI output. Wouldn't this hamper your ability to split the DVI signal?


Which is why you need the component adapter after you split the DVI signal. If my ascii diagram's hadn't gotten munged you'd see that's exactly what i did...
 

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Discussion Starter · #13 ·
Quote:
Originally posted by ADU
Per wienerdog,


I think you may have trouble getting the DVI port to drive both an RGB (FPD) and YPrBr (HDTV) display simultaneously with this setup. For this to work, I suspect ATI's DVI-I-to-component adapter would need to passively convert RGB to YPbPr. Unfortunately, I think it needs a little help from the Catalyst drivers to get the YPbPr rolling.
My FPD is not RGB. it's native DVI. I"m using "Flat Panel Display" interchangeably with LCD display...


So i'm not doing anything involving RGB, just DVI and YPrPb


--goolz
 

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Discussion Starter · #14 ·
Quote:
Originally posted by RichCarling
My interpretation is that you want to directly drive the HDTV and the LCD (although probably a CRT would work better directly from the DVI. He is using the DVI splitter box to get clean amplified DVI signals, and would probably set the ATI resolution (or using scaler) to the native HTDV resolution.
Yes, this is what I'm trying to do.

Quote:


The one problem I see is that the resolutions would have to match, and we all know that LCD screens usually look very bad when not matched to their native resolution. Since we also want the native (and possibly uncompatible) resolution of the HDTV, this may not be a very workable solution (and a $299 DVI splitter box kind of defeats any cost saving over a new video card).
This is one of my issues. I can't find what the native resolution(s) of the Panasonic HDTV is/are. I think Panasonic's tech support was quite possibly the worst joke I've ever had the misfortune of hearing. I called them, spent 25 minutes on hold, and the moron on the other end knew nothing other then what was on her computer screen. She even tried to tell me i didn't have an HDTV.


Any ideas on how I could find out what resolution it supports? It sez it's "1080i compatable" but that's a timing thing not a resolution thing right?

Quote:
Perhaps a dual DVI graphics would be the better way to go, or using an analog driver for one of the outputs and using the more readily available dual monitor capable ATI cards. Unfortunately I believe all ATI cards are either dual monitor or AIW and not both. I would believe that within the next 12 months we will start to see video card makers providing this kind of support directly, probably providing a component video and DVI with a HDTV AIW single card solution.
As i said in my original post, the only dual DVI I'm aware of is the Matrox (at least the only one in a reasonable price range, say under $400), and it doesn't have acceptable performance...
 

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Discussion Starter · #15 ·
Quote:
Originally posted by DWAnderson
I spent a bunch of time researching this a few months ago and I believe my conclusion (per information on the ATI website) was that this is true for all of the ATI cards except the ATI AIW 9700 Pro. I believe it has the ability (with a dongle) to support component output to one screen and analog output to an LCD monitor simultaneously. I had wanted to use the LCD monitor for PC UI stuff and the component outputs would be used to display video files only.


I never got deeper into this because the $400+ price of the card at the time made me decide to put off my dreams until this card came down in price some more.


If anyone else actually set this up I'd be interested in hearing about it.


Doug
Yes, this was one of the alternate configurations I was considering. I think you're right about the 9700 pro supporting dual output. It seems to have come down to about $300 right now...
 

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Discussion Starter · #17 ·
I just got some email from Dave and Pacific Custom Cable... I basically said that I was concerned about getting DVI-A cables to go to the ATI

component adapter, because it's labeled as a "DVI-I to YPrPb" adapter. So doesn't it require a DVI-I cable?


Dave said, " Analog signals are all you can use to component. DVI-A is it."


The nice thing about the DVI-A cables is that long ones are supported; they sell a 15 meter (50 foot) DVI-A cable for 40 bucks.


I'm still nervous about it. Anyone have any impressions?
 

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Discussion Starter · #19 ·
Quote:
Originally posted by Karnis
Why not go DVI directly to your FPD and use a transcoder on the VGA port to your HDTV?
I may be misunderstanding your questions, but the 8500dv and the dvi splitter only have DVI outputs. THere are no VGA outs in my current configuration.


The other issue is that if i do anything other then DVI, i can't use the ATI component adapter and therefore loose the increased resolution that it affords. Unless there is something else on the market that will convert VGA into hi resolution YPrPb HDTV signal. Gefin makes such a box, but it's $400.
 

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Ah ha, sorry 'bout that.

Seeing in your previous posts in this thread, money is not a problem? I would upgrade your video card with a 9500/9700, or something like that with DVI & VGA ports, send the DVI to your FPD, get a transcoder (
 
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