Why some LCD TV's look fine as PC monitor while others dont? - AVS Forum
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post #1 of 11 Old 03-02-2011, 01:37 PM - Thread Starter
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What I'm referring to, and consider this prior to responding, isn't visible by everyone. If you're the kind of person that's immediately annoyed when you sit down at an LCD monitor on a PC that's set for a resolution other than the manufacturer's native resolution, you know what I'm referring to. Scenarios where a person increases the resolution to "make the fonts bigger" rather than keep the proper resolution and adjust the DPI.

I'd like to know if there's a word for this, or a proper description to define this specific difference and I'll do my best to describe:


In my living room, I have an LG 47LG70 LCD display, at 1080p and it's plugged into my A/V receiver which then has my HTPC plugged into it (amongst other things) via HDMI.

The text on my 47" living room TV is perfectly crisp and clear at 1920 x 1080. Small fonts, 9 point, at 96 pixels per inch look absolutely fine, just as nice as they do on a good quality LCD display advertised as a PC monitor.

However, I'm finding myself working with friends that buy expensive TV's, that look like absolute crap when interfaced with a PC via HDMI. They look nothing like my LCD TV on my HDMI PC. It's difficult to explain, but the text is not crisp and clear, not exactly fuzzy but it's not 'perfect' when it's a smaller point font. Really small fonts that look fine on my TV (up close) are almost illegible on their TV's. Furthermore, some colours over other colours, like system tray icons, produce an effect that looks like colour bleeding, or isolated ghosting.

So, when I have a person who tells me he wants to connect a big TV to his PC, what can I tell him to look for to ensure that the picture will be crisp and clear enough with a PC. "Expensive Sony TV" is not cutting it, there's something outside of price...

Anyone with learned advice that can provide me with accurate information? Much appreciated!


Note, I posted this in another forum as I completely forgot that this forum would be far more suitable; the responses I received there were good attempts but it's still a question of what it is. Note, in all instances of comparing, directly using HDMI (no adapters) and these are new LCD's advertised as 1080P and it doesn't look like an over scan issue, it looks like more of a quality problem.
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post #2 of 11 Old 03-02-2011, 08:16 PM
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One reason might be with the way the sub-pixels in the TV are aligned. Many LCD TV panels aren't specifically designed to be used with computers so text might not be as clear as LCD monitors. Some models that come to mind are Sharp and Panasonic TVs. LG on the other hand makes a lot of displays for PC monitors so there is a good chance their TV displays should look fine. Overall it really is a crapshoot with regard to how well text will look due to the fact that not all TVs use the same kind of LCD panel consistently even within identical models. If I had to choose I would stick to LG, Sony and Samsung.
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post #3 of 11 Old 03-02-2011, 08:21 PM
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Quote:
Originally Posted by urbanriot View Post

What I'm referring to, and consider this prior to responding, isn't visible by everyone. If you're the kind of person that's immediately annoyed when you sit down at an LCD monitor on a PC that's set for a resolution other than the manufacturer's native resolution, you know what I'm referring to. Scenarios where a person increases the resolution to "make the fonts bigger" rather than keep the proper resolution and adjust the DPI.

I'd like to know if there's a word for this, or a proper description to define this specific difference and I'll do my best to describe:


In my living room, I have an LG 47LG70 LCD display, at 1080p and it's plugged into my A/V receiver which then has my HTPC plugged into it (amongst other things) via HDMI.

The text on my 47" living room TV is perfectly crisp and clear at 1920 x 1080. Small fonts, 9 point, at 96 pixels per inch look absolutely fine, just as nice as they do on a good quality LCD display advertised as a PC monitor.

However, I'm finding myself working with friends that buy expensive TV's, that look like absolute crap when interfaced with a PC via HDMI. They look nothing like my LCD TV on my HDMI PC. It's difficult to explain, but the text is not crisp and clear, not exactly fuzzy but it's not 'perfect' when it's a smaller point font. Really small fonts that look fine on my TV (up close) are almost illegible on their TV's. Furthermore, some colours over other colours, like system tray icons, produce an effect that looks like colour bleeding, or isolated ghosting.

So, when I have a person who tells me he wants to connect a big TV to his PC, what can I tell him to look for to ensure that the picture will be crisp and clear enough with a PC. "Expensive Sony TV" is not cutting it, there's something outside of price...

Anyone with learned advice that can provide me with accurate information? Much appreciated!


Note, I posted this in another forum as I completely forgot that this forum would be far more suitable; the responses I received there were good attempts but it's still a question of what it is. Note, in all instances of comparing, directly using HDMI (no adapters) and these are new LCD's advertised as 1080P and it doesn't look like an over scan issue, it looks like more of a quality problem.


I read something about this the other day around here.Did you try searching for it ?
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post #4 of 11 Old 03-02-2011, 09:45 PM - Thread Starter
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Quote:
Originally Posted by Rightwing View Post

I read something about this the other day around here.Did you try searching for it ?

Yes sir, and the results were many... none of them related to my question.

So far two out of two brand new 37" 1080p Sony LCD TV's are not able to crisply display video on a PC. Passable, sure, but not 'great' and not something I'd live with.
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post #5 of 11 Old 03-03-2011, 10:51 AM
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Your TV apparently supports chroma 4:4:4. Their TVs do not.
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post #6 of 11 Old 03-03-2011, 12:24 PM - Thread Starter
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Quote:
Originally Posted by Lord Humongous View Post

Your TV apparently supports chroma 4:4:4. Their TVs do not.

Interesting, that's the first I've heard of this, thank you!

I searched the forum to find more information and happened upon this thread: http://www.avsforum.com/avs-vb/showthread.php?t=1292135

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Originally Posted by thepoohcontinuum View Post

I agree with Michael2000 on all points. The lack of 4:4:4 chroma will cause edges to blurry and color uniformity will be slightly off.

From what I read this chroma 4:4:4 support isn't standard and I'm 'lucky' in a way, that I accidentally purchased a TV that supports it. I tried to google information that directly states this, regarding my TV, and only found some people discussing it but no firm details.

Is it impossible to determine this information prior to buying an LCD, without speaking with other people that own this LCD and actually know what it means?

Thanks again.
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post #7 of 11 Old 03-04-2011, 02:43 PM
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It all comes down to matching the native resolution of the set to the PC output. If the output is anything but the set's matrix, then the set has to scale the image. This is the likely cause of the lack of crispness or focus. A HDMI output may be defaulting to a different resolution that what the PC thinks its outputing. Try DVI instead.
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post #8 of 11 Old 03-04-2011, 04:39 PM
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To the OP:

Check out the phrase "one to one pixel mapping" Also if the TV is set to 30HZ 1080i instead of 60HZ 1080P, it will look like crap. I found that out recently when updating my ATI drivers.
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post #9 of 11 Old 03-07-2011, 05:57 AM - Thread Starter
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Quote:
Originally Posted by DBLASS View Post

A HDMI output may be defaulting to a different resolution that what the PC thinks its outputing.

So, a brand new, name brand TV advertised as 1080p is actually not outputting at 1080p? I'd thought this hadn't been an issue in the past few years... ? At least not with higher priced LCD's.

Quote:
Originally Posted by DBLASS View Post

Try DVI instead.

I don't see too many displays these days with DVI ports, at least not the Sony's or LG's people are buying. I only wish they all had DVI, it would make my life easier. When my parents were shopping for a new TV two months ago, they had an impossible time finding a new 42" LCD with a DVI port.

Quote:
Originally Posted by PoppaC View Post

Check out the phrase "one to one pixel mapping" Also if the TV is set to 30HZ 1080i instead of 60HZ 1080P, it will look like crap. I found that out recently when updating my ATI drivers.

Thanks for the suggestions, issue I don't believe to be related to one to one pixel mapping or scaling, but I've added it to my text file of considerations for future LCD purchases. It seems this is less of an issue today than it was 4 - 5 years ago.

This isn't a frequency problem, but thanks for the suggestion. That setting has an effect that doesn't look the same as what I experienced that prompted this thread.

After reading more on related topics and 'chroma 4:4:4' subsampling, I'd say Lord Humongous was bang on with his suggestion, as further research has shown that a good friend's LG LCD that's plugged into his HTPC also supports it, his experience is as excellent as mine... while everyone else's LCD I've tested with a laptop, mostly Sony's, have been similar in experience to what prompted me to enquire about this issue. I only wish I could find out how I can officially verify an LCD supports 4:4:4 or not...
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post #10 of 11 Old 03-07-2011, 02:36 PM
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It's the PC that has to output to the TV. 1080P is 1920 x 1080 pixels. The PC has to output that to match the set. Otherwise, it is scaling which will cause a lack of crispness.
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post #11 of 11 Old 03-07-2011, 03:09 PM
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Is 4:4:4 only related to colored text? (i.e. red text on a black background).

I don't have experience myself, but I've heard certain TVs have (sometimes designated) HDMI inputs that can be renamed to PC. After renaming the input, text will be a lot more clear. I've heard this complaint many times for people using PC monitors via HDMI also. Try searching for that.
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