why cant you connect to a PC via HDMI/DVI?

[nineinone]

I'm looking at buying a 40' LCD TV to connect to my PC.

But seemingly even the highest end models from Samsung and Sony explicitly state in the manual NOT to connect to a PC via the HDMI/DVI In, and instead use the analog RGB/PC IN. this seems to make absolutely no sense!

is this really the case or just BS? why would these TV's accept DVI signals from everything OTHER than a PC?

[edDV]

To be blunt: They don't want to deal with the likes of you.

They want to sell these as TV sets not as PC monitors with all the issues that implies.

More questions?

[edDV]

If you come in over YPbPr, the burden is on you to supply a standard 480i, 480p, 720p, 1080i format. Most recent ATI and NVidia video oriented cards will do that over YPbPr.

Over DVI/HDMI th burden is on the TV manufacturer as to what they will let in or deny in the port ROM. Again they must allow 480i, 480p, 720p, 1080i formats to work with other manufacturer's equipment or even their own.

You probably want to feed some kind of VESA computer resolution. You are clueless. They don't want to spend more to allow that in hardware and support. Why? Because they would have to hire and train all those Indian or Southeast Asian support techs and that wouldn't be necessary if only they banned computer connection. They know you will generate more in support cost than they make on that TV.

Are you hearing me?

So, what do you do? You look carefully for computer support in specs for these monitors. You download the manual and see which VESA resolutions are specifically supported. If you like what they offer you buy it.

If it is in the spec and it doesn't work, then you can beat them up and refuse VISA/Mastercharge payment.

[ZAPPER]

To be blunt: They don't want to deal with the likes of you.

They want to sell these as TV sets not as PC monitors with all the issues that implies.

More questions?

Dude.

Rough day at work?

[nineinone]

jeez, look, I can understand plenty of the "evil" reasoning behind it as suggested, but what I cant understand is someone, other than say just the manufacturers, somehow defending this kind of thing like its reasonable, ie intentionally dumbing down new products.

the only real question now is, does it "really" not work? is the "dont connect this way" stuff just bravado to dissuade us? In fact, in one manual I saw, it actually has right on the diagram next to the HDMI slot, something like "dont connect your PC here" almost like advertising it, as opposed to just mentioning the RGB connection where it "does" work. They are actually going out of their way to say NOT to use the HDMI.

I mean, if it is just really a DVI signal coming into the display, are they actually intentionally telling the display not to accept the signal? I'm no expert obviously, but I dont understand why the TV should "care" if the DVD movie signal its getting is coming from a PC as opposed to a standalone DVD player? Or is this just similar to something like HDCP where it will just refuse to play a signal coming from a PC?

[edDV]

To be blunt: They don't want to deal with the likes of you.

They want to sell these as TV sets not as PC monitors with all the issues that implies.

More questions?

Dude.

Rough day at work?

Sorta rough yeah but I was trying to get to the point without the education. I did come back later with explanation.

[edDV]

...

They are actually going out of their way to say NOT to use the HDMI.

I mean, if it is just really a DVI signal coming into the display, are they actually intentionally telling the display not to accept the signal? I'm no expert obviously, but I dont understand why the TV should "care" if the DVD movie signal its getting is coming from a PC as opposed to a standalone DVD player? Or is this just similar to something like HDCP where it will just refuse to play a signal coming from a PC?

The HDTV manufacturer must accept defined video resolutions and frame rates over YPbPr (e.g. 480i, 480p, 1080i plus 720p sometimes and 1080p rarely).

Some provide a separate VGA DB15 connector with explicit PC connection specs and specific VESA resolutions and refresh rates. These are all square pixel. Some but not many will do this for DVI-D.

On the DVI or HDMI video connectors they have the power of the port fimware to let in what they please. This is a separate issue from port encryption (HDCP).

You can be assured they accept the basic SD resolutions like 720x480i/29.97 and 720x480p/59.94. On early sets but not all newer ones 640x480p/60 square pixel was a given.

PAL resolutions of 720x576i/25 and 720x576p/50 are a maybe.

HD resolutions of 1280x720p/59.94, 1280x720p/29.97, 1280x720/23.976, 1920x1080i/29.97, 1920x1080p/23.976 are optionally supported by the manufaturer because each needs specific image processing to map to the native HDTV display.

VESA square pixel resolutions of:

CGA | EGA | VGA | MCGA | 8514 | XGA | QVGA | VGA | SVGA | XGA | SXGA | SXGA+ | UXGA | QXGA | QSXGA | QUXGA | HXGA | HSXGA | HUXGA |

and the Widescreen variants

WXGA | WSXGA/WXGA+ | WSXGA+ | WUXGA | WQXGA | WQSXGA | WHXGA | WHSXGA | WHUXGA | WQUXGA

http://en.wikipedia.org/wiki/Image:Video_Standards.PNG

all would need specific resizing to the native HDTV panel resolution and refresh limits would have to be 60Hz +/- a fraction for NTSC or 50/100Hz +/- a fraction for PAL areas.

There would also be all the SD and HD letterbox and pillarbox issues.

Can you imagine training the customer service department to respond to all the, aspect ratio, resolution and refresh frequency complaints?

The easy solution is to limit supported formats in ROM at the port.

[MrSnake]

Well, "evil conspiracies" or not, I think it's very confusing from the manufacturers that you can't see which connectors support what outputs. I mean they list "1080p capable" and a whole list of connectors.

How can you possibly know?
Even if they have printed it in the manual, it'll be vague and you can't possibly ask for all manuals when buying a TV.

e.g. Sony Bravia 46" LCD-TV KDL-46X2000

It supports full 1080p, when you check the website it says they support 1080p, but when you check the manual they don't support 1080p... (except for some certain connectors, which wasn't very clear in the manual in my opinion).

So I hook it up on my PC via VGA/RGB etc... but the TV itself doesn't get any higher then 1360x768.
If you set it to 1920x1080 you get some severe overscan.

The only way to get the thru 1080p can only be done by HDMI connector, which I don't have yet.

I can imagine a lot of people will get misled by this kind of marketing.

[Krispy Kritter]

Well, "evil conspiracies" or not, I think it's very confusing from the manufacturers that you can't see which connectors support what outputs. I mean they list "1080p capable" and a whole list of connectors.

How can you possibly know?
Even if they have printed it in the manual, it'll be vague and you can't possibly ask for all manuals when buying a TV.

e.g. Sony Bravia 46" LCD-TV KDL-46X2000

It supports full 1080p, when you check the website it says they support 1080p, but when you check the manual they don't support 1080p... (except for some certain connectors, which wasn't very clear in the manual in my opinion).

So I hook it up on my PC via VGA/RGB etc... but the TV itself doesn't get any higher then 1360x768.
If you set it to 1920x1080 you get some severe overscan.

The only way to get the thru 1080p can only be done by HDMI connector, which I don't have yet.

I can imagine a lot of people will get misled by this kind of marketing.

You can't blame the manufacturer for the consumer not being educated.

[neomaine]

MrSnake,

I've heard of some success with setting your video card to 1920x1200 instead of 1920x1080 for 1080p capable TVs. Though this may be specific to the Sceptre 42" LCD (which I have but haven't hooked up to my PC yet) you may want to give it a try.

It also could very well be that the manufaturer, Sony in this case, only supports up to 720p on the VGA port. Not sure why they'd do that...but, I've heard of stranger things.

[edDV]

The VGA port supports VESA resolutions (see above) with a maximum resolution set in port ROM. Experiment.

1080i, 720p etc. are supported on YPbPr and HDMI

1080p may only be supported on HDMI.

Most TV products have downloadable manuals and you can call Sony for clarification before buying anything.

[sorinicu]

Even worse... For some 1080p sets, the 1080p is DISPLAYED resolution, but none of the connectors can accept more than 1080i. Some kind of upconversion to 1080p is done..

[painkiller]

nineinone said

why would these TV's accept DVI signals from everything OTHER than a PC?

From ATI's website -

Radeon® X1800 CrossFire™ Edition PCI Express® 512MB
part of its specs:
Display Support
Integrated dual-link DVI for high-resolution digital displays
DVI-I connector for digital CRTs or flat panels

My ATI XL800 series display card also has a DVI port on it.

Honestly, I don't see a problem. Provided the flat panel TV I buy actually has a DVI port.

[edDV]

Honestly, I don't see a problem. Provided the flat panel TV I buy actually has a DVI port.

This is true.

You don't understand the problem.

[painkiller]

For what it is worth to you, EdDV, I thought you and others (above) spoke well of the resolution issues as they related to this situation.

And I quite agree. I just didn't want to extend the same language that I thought all of you handled so nicely.

I just felt a short, quick message to the first individual - nineinone - maybe perhaps wasn't aware he could actually use (and perhaps didn't have) a display card that has a DVI connector.

I for one am not concerned that an OEM suggests that I do not use this connection.

After all, I can try it out for myself and make my own judgement if it is worth my time.

[edDV]

For what it is worth to you, EdDV, I thought you and others (above) spoke well of the resolution issues as they related to this situation.

And I quite agree. I just didn't want to extend the same language that I thought all of you handled so nicely.

I just felt a short, quick message to the first individual - nineinone - maybe perhaps wasn't aware he could actually use (and perhaps didn't have) a display card that has a DVI connector.

I for one am not concerned that an OEM suggests that I do not use this connection.

But the issue of computer connection by other than video resolutions (1080i, 720p, 576p, 576i, 480p, 480i and supported frame rates) remains.

TV sets normally don't support VESA computer resolutions even if they do have a DVI port. They aren't a multi-sync computer monitor and don't behave like one. They only support specific resolutions and frame rates as stated in their specifications in the manual. Understand what is supported before you buy.

On top of this HDCP encryption if and when implemented will inhibit copy protected playback unless both ends of the connection handshake with correct keys.

After all, I can try it out for myself and make my own judgement if it is worth my time.

Be aware that many early HDTV sets can be damaged by feeding unsupproted frame rates. This is unlikely to happen with DVI or HDMI because invalid requests are blocked at the port ROM.

[paulw]

You could possibly try one of these HDMI graphics cards
http://www.cdrinfo.com/Sections/News/Details.aspx?NewsId=16758

[sorinicu]

You could possibly try one of these HDMI graphics cards
http://www.cdrinfo.com/Sections/News/Details.aspx?NewsId=16758

Which none of them support HDCP. Without that you will not be able to play a HD DVD. Sure, the games will be in HD... but wait thre are allready better than HD on all the current videocards that support more than 1240x1024.
Anyway, is not what the initial topic was about - incapability of a LCD TV to support other resolutions than the standard HD ones. How a different PC video card can help with that is a secret I guess...

[kurbads]

They sell large LCD TVs without proper PC connection because people by them. The LCD market is 10% of TV set market and PC connectable LCDs are 10% of LCD market. It is 1%. Industry is not in a hurry to offer what is not demanded yet. When people will start realize and demand TVs with conection there will be a lot of TVs sold without it. People will have to throw out them and buy new ones. Thats an industrie's plan - no conspiracy. It is called product life cycle. The same thing was Mp3 support on DVD players. Since DVD already has mp2 decoder to play mpeg2 what was reason to support not mp3 initially?

[SingSing]

It has more to do with market focus and economic of scale.

The LCD monitor makers are not going to add video input and add cost, and loose their market share.

The LCD TV makers are not going to add PC input and add cost, and loose their market share.

There will be models made to capture the small segement of the market where people are willing to pay more to get what they want, and have the known how to make it work.

[edDV]

There seems to be a trend in the latest LCD TV sets to offer a "computer" VGA port that supports certain VESA resolutions like 1024x768, 1280x1024, or 1280x768 (wide), 1366x768 (wide) or even 1400x900 (wide). You really need to read the specs BEFORE you buy anything.

The "computer" input is intended for a PC desktop or MCE graphics card* connection. Usually there is no overscan on the VGA port. The DVI/HDMI video resolution inputs usually overscan 5-10% to keep the peeps from complaining about edge video crap. 5-10% overscan will cause edges of desktop XP menus to fall off screen.


* Fancy MCE cards like the "AVIVO" and "Pure Video" models provide overscan modes on the card.

[kurbads]

Quite expensive, but probably one of the ways to connect HDMI TV digitaly: http://www.apple.com/macmini/accessories.html

[edDV]

Quite expensive, but probably one of the ways to connect HDMI TV digitaly: http://www.apple.com/macmini/accessories.html

Please explain how a MacMini is any different at all? Isn't the problem mostly with the LCD-TV and the resolutions and frame rates it accepts?

The MacMini has the same DVI-I connector and a very basic Graphics processor by PC standards, an Intel GMA 950 same as is used on lowest end PC's. It does have a VGA split off DVI-I that supports up to 1920 by 1200 pixels, but so do many ATI and NVidia cards. So what is the advantage of any Apple Mac for feeding a LCD-TV? I don't see one.

http://www.apple.com/macmini/specs.html
"Graphics and Video Support
Intel GMA 950 graphics processor with 64MB of DDR2 SDRAM shared with main memory(1)
DVI video output to support digital resolutions up to 1920 by 1200 pixels; supports 20-inch Apple Cinema Display and 23-inch Apple Cinema HD Display; supports coherent digital displays up to 154MHz; supports noncoherent digital displays up to 135MHz
VGA video output (using included adapter) to support analog resolutions up to 1920 by 1080 pixels
S-video and composite video output to connect directly to a TV or projector (using Apple DVI to Video Adapter, sold separately)"


PS: Funny that an Apple.com "advanced search" for HDCP returns "no documents found", also "Did you mean DHCP ?”. Apple has been selling these >$2000 Cinema HD Displays, never informing the buyer that they won't play a HD or BD DVD with HDCP encryption turned on and never will short of a recall.

[kurbads]

I gave a link to page with MacMini accesories because they work for any PC too.
That page has following information:
"HDMI is electrically similar to DVI, but has a different physical connector that may include an audio signal. You’ll need a DVI to HDMI adapter, such as the Belkin PureAV HDMI to DVI cable to use these televisions. You may need a seperate audio cable (see below.)"


The link strangely refers not to DVI to HDMI adapter, but HDMI to DVI cable. And it costs $119. Thats why I call it expensive.

Probably it is just marketing trick, not a real LCD TV support.

[SingSing]

DVD player's optical cable is not very common because the coaxial cable fullfilled the same need.

The real need for a connection like HDMI is mostly digital video, because most consumer will run their audio thru a seperate surround sound amp/speakers.

If the HDMI cables persist at a very high cost. Cosumer will vote with another approach and their dollars - The ultimate specification.

[edDV]

I gave a link to page with MacMini accesories because they work for any PC too. ...

The link strangely refers not to DVI to HDMI adapter, but HDMI to DVI cable. And it costs $119. Thats why I call it expensive.

Probably it is just marketing trick, not a real LCD TV support.

But the problem is not only related to a hardware cable adapter from DVI-I to HDMI and a separate audio cable. It is much more complicated. BTW, you can get the Philips DVI-I to HDMI cable for around $20 at Sam's or Wal-Mart and less online if you shop.

The problems hooking a computer to a LCD-TV are as follows:

1. Most LCD-TV (also plasmas, etc.) don't accept normal VESA resolutions and frame rates that computer display cards put out. They want video resolutions* at 50 or 59.94Hz refresh. These refresh rates are too flickery for a windowed computer display but are fine for video display.

2. Most LCD-TV (also plasmas, etc.) overscan 5-10% for the video inputs (YPbPr, DVI, HDMI). This causes the edges of a windowed computer display (where the menus are) to fall off screen. Some display cards will shrink the window display to compensate for overscan. Others don't.

3. Some LCD-TV (also plasmas, etc.) will offer a "computer port" (usually VGA) or special DVI/HDMI modes that support a limited set of VESA square pixel resolutions and/or turn off overscan. Consider these the exception, not the rule. Make sure the HDTV will accept what your computer display card puts out before you buy the TV. Otherwise use a computer monitor, not an LCD-TV.

4. Even if the LCD-TV accepts computer resolutions, most will force you to use 59.94 or 50Hz refresh. I find 59.94Hz refresh flickery for windowed computer displays (black over white) and 50Hz unwatchable. Computer display refresh should be in the 75-85Hz and up range.


* Supported video resolutions are usually 1080i, 576i, 576p, 480i and 480p. 720p is not always supported but that is what you want for hooking a computer to the typical LCD or plasma HDTV display. 1080p is rarely supported even for 1080p displays. 1080p is usually up interpolated from 1080i or lower resolutions only.

[kurbads]

Computer display refresh should be in the 75-85Hz and up range.

75-85Hz is required for CRT displays. Optimal is 100Hz because the human eyes' refresh rate is about 98Hz.
This is not true for LCD displays. Most LCD monitors have only one refresh rate - 60Hz and I found it OK. The eyes do not tire.
All computer video cards offer 60Hz refresh rate which is almost 59.8Hz and any NTSC TV will most probably adopt to it.
To fight the overscan the start menu bar can be stretched up to appear on desktop. Other sides can be covered with blank Windows Desktop toolbars with Always on Top setting.
Of course, I will wait for normal 1920x1080 TV with DVI link for under 1.5$ in my city. It's just matter of time.

[edDV]

Computer display refresh should be in the 75-85Hz and up range.

75-85Hz is required for CRT displays. Optimal is 100Hz because the human eyes' refresh rate is about 98Hz.
This is not true for LCD displays. Most LCD monitors have only one refresh rate - 60Hz and I found it OK. The eyes do not tire.

How about Plasma and DLP?

[edDV]

To fight the overscan the start menu bar can be stretched up to appear on desktop. Other sides can be covered with blank Windows Desktop toolbars with Always on Top setting.

We are used to having H&V size and position controls on our PC monitors but LCD-TV's often lack these controls. The burden falls to the display card to resize and position the desktop.

[jlynn33]

I am currently looking at my 37" lcd tv that I use for a monitor 24 hours a day to type this reply. It is a Syntax Olevia and is super nice! The tv takes it's signal from a dvi port on my geforce 6800gt 256mb video card inside my pc. The picture resolution is set at 1280x720 and fills the screen. The tv only will accept up to a 1366x768 signal so 1280x720 is the closest with normal pc resolutions. I have heard you can use powerstrip to get it to 1360x768 but am not interested. Looks great at 1280x720! I would whole hardily recommend an lcd tv as a monitor! Now, I just need a bigger one! :P