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HDMI poor quality displaying text compared to DVI

yf38 Community Member
Currently Being Moderated

Hi all,

The subject is:
With HDMI port of Intel integrated graphics I get a visibly lower quality of text display than when using the DVI port.

Hardware:
motherboards: DH67GD and also DG45ID using Intel graphics.
Display: HP 2159m native resolution 1920x1080 60Hz, no scaling at display, last revision of the "driver" defined as windows 7 compatible.

Software:
windows 7 x64 home premium, up to date, before and after upgraded to SP1, all drivers are the latest from Intel.

Observed:
When using HDMI port, the Intel graphics control panel enforces some overscan even when I select the first scaling option to keep the original size (no sclaling expected should be for me 1920x1080).
To fit the screen which is exactly 1920x1080 I need to select the second option to scale down with the value 50 to get the right size.
Doing this, a scaling is applied and the text is somewhat blurried (which I may understand).
The clear type tuning of windows 7 (applied before scalings) can't improve the text to make it as good as with DVI display.

What is wrong, in my opinion, is this extra overscan performed even when we select the option to keep the original size, and makes necessary a subsequent underscan.
This overscan is not present when using DVI port, only with HDMI.
Associated with HDMI the display monitor is defined as "digital television"  (and I have no choice) on the contrary of DVI where it is known as a

computer display.

A  Sapphire radeon HD4550 with the same systems, doesn't produce the same issue.
The scaling factor with this card allows an underscan only and if kept at 0% the text display is crisp like with DVI meaning that probably no scaling at all is performed in this 0% case.

Question:
Does somebody know a workaround to this issue, mainly in order to have no initial overscan in HDMI, to be capable of using the option to avoid scaling.


  • 1. Re: HDMI poor quality displaying text compared to DVI
    yf38 Community Member
    Currently Being Moderated

    Hi again,
    Googleing a lot I found somebody with the same issue and he proposed a solution to cancel the initial overscan that works.
    You can find it at:
    http://www.cybersprocket.com/2011/gadgets/hp-2509m-display-truncating-with-intel-hd-graphics/
    The interesting part is the chapter to cancel the initial overscan.
    In summary, in the Graphics control panel in advanced mode:
    Assuming you are with the HDMI monitor and have compensate the overscan as said in the first post:
    - create a custum resolution 1920x1080 60Hz 32bit with 0 underscan percentage (slide) and CVT-RB timing standard.
    - clic on add and accept to overwrite the existing resolution.
    At this moment the resolution is applied and the screen becomes underscanned.
    - go back to global parameters and cancel the scaling by selecting 100% on the two slides, and if available the first option to maintain the native size.(seems to have been removed with driver 2291).
    The image now is filling the screen and the text is as good as in DVI mode.

    Hope this will help people with the same issue, and not only for text because when text is fine video is even better.

  • 2. Re: HDMI poor quality displaying text compared to DVI
    Currently Being Moderated

    Thanks that help a lot

  • 3. Re: HDMI poor quality displaying text compared to DVI
    yf38 Community Member
    Currently Being Moderated

    Hi,

    With the newer drivers I didnt check if the issue and the solution are still the same. Reading your post it looks like yes.

  • 4. Re: HDMI poor quality displaying text compared to DVI
    Currently Being Moderated

    I've got a  http://www.newegg.com/Product/Product.aspx?Item=N82E16834230026 hooked up to a http://www.afterdawn.com/products/product_details.cfm/2753/vizio_l42hdtv10a

     

    It's an older TV, but man has it been amazing. Anyway, I'm having the same issues here. I went into the custom resolution and created 1280 x 720p (windows tells me thats its native even though it supports 1080p) with 0 underscanning. GTF timing will offset the entire picture to the right and the top and bottom of the picture will run off the side of the monitor. CVT will make it do the same thing except the picture offsets to the left and CVT RB will actually just make the tv flicker and it puts the picutre way way to the left... So far the way I've been using it is I've got it set to the non custom 1280x720 and I scale the ratio by 40 percent vertical and horizontal and it all fits on there in the center but the text is pretty lousy. Videos look fine though.

     

    Anyone got any ideas?

  • 5. Re: HDMI poor quality displaying text compared to DVI
    yf38 Community Member
    Currently Being Moderated

    Hi,
    setting a custom resolution in Intel graphics when the monitor is seen as a digital TV instead of a monitor, is a workaround to cancel the initial ovescan set by the driver.
    Any resizing of the picture has a bad effect more visible with text screens.

    The problem with your TV is probably that it does not accept a 1366x768 input resolution thru HDMI, only the more standard 1280x720 in TV world, and it performs a resizing to fit the 1366x768 native resolution of the screen.
    It would do the same if you send it a 1920x1080 data, resizing down.

    The only way to have no resizing would be to use a 1366x768 custom resolution  using a TV input doing no resizing.

    Try to connect the TV using a VGA cable and set everything to 1366x768 and no rescaling in TV menu if any.
    Analog is not as good as digital, but in this case it may be, provided your TV accepts this computer resolution in VGA.

     

    Instead of 60Hz it may be necessary to use 59. (also with 1920x1080 I discussed earlier).

    Because VGA does not carry audio, you should find another path for audio, from the line output.

  • 6. Re: HDMI poor quality displaying text compared to DVI
    Currently Being Moderated

    Well, I appreciate the advice but I'll probably stick with the hdmi. I'd have to use analog audio if I were to use RGB. Which looks great by the way.

  • 7. Re: HDMI poor quality displaying text compared to DVI
    cwatkin Community Member
    Currently Being Moderated

    I found a workaround to this issue for now. Basically, I took one of those DVI to HDMI converters and plugged the cable into the DVI port of my monitor instead of HDMI. So, I have an HDMI cable coming out of the laptop, then being converted to DVI on my monitor. The Intel HD no longer sees this as a digital TV and no longer runs at 59 HZ with the overscan issue.

     

    For those of you who have the same problem and have an unused DVI port on your monitor, there are several ways to adapt this without spending much money. There are plenty of cables and converters to choose from if you look at buying one online. I cannot say this would work on any monitor but it did on mine. I have an HP 2709m which is a 27 inch LCD and have seen others referencing the same problem with an HP 2509m so I guess it would work on that one too. The one issue is if you only have one DVI port and need it, you will then need to convert DVI to HDMI to input that data. Unless you are using the same Intel HD graphics, it may work fine. Also, maybe this would also work without overscanning??? I don't know.

     

    Anyway, I thought it was good to share this workaround.

     

    Conor

  • 8. Re: HDMI poor quality displaying text compared to DVI
    yudonglei16 Community Member
    Currently Being Moderated

    what is your cpu model in your laptop ?

     

    I've got a problem about connecting my laptop to lcd tv via hdmi-to-hdmi. The HDMI port is handled by SNB i3 2350m with the newest graphics driver. The resolution is OK and so does the scanning(non-over scanning).But the text on tv looks jagged or blurred or oversharpened also the colors looks washed out and over bright. I tried to adjust fuctions in OSD even in factory mode,didn't get any better. After that I found some information by searching. I've found that my lcd tv(actually most of lcd TVs) is able to recognize and deal with the  DVI signal via HDMI connection(be compatible with DVI-HDMI adapter) . In this way,text and colors go back to as normal as monitors. Someone force display adapter (nvidia) to send out DVI signal during HDMI-HDMI connection by editing the EDID hex value to disable EDID extensional block(contain extra information of HDMI input device ) then make an *inf file as driver of tv. It works well on nvidia cards but not on my SNB i3. I'm not sure if it's driver of graphics' fault or SNB Integrated Graphics can only send out HDMI mode signal via HDMI port.

     

    You have said that you connected monitor and laptop by HDMI-to-DVI converters successfully.  is it SNB ?

  • 9. Re: HDMI poor quality displaying text compared to DVI
    yf38 Community Member
    Currently Being Moderated

    Hi,

    With Sandy bridge and Intel's graphics drivers (up to now), when the monitor is detected as " digital TV" then there is an initial overscan done by the driver.

    This is with HDMI port.

    I gave, in the second post, a solution I found using a "customized resolution".

    This is not to define a different resolution, but just to workaround this damned initial overscan.

    There are other workarounds discussed here, all probabaly trying to make the driver no more detecting the monitor as a "digital TV", such as DVI / hdmi adapters or EDID hacking, but there is no need to use such workarounds to connect hdmi to hdmi,  if you apply the customized resolution one.

    You said  "resolution is good" maybe because you tuned at some moment the slide to resize within Intel's graphics menu, but this is not a solution.

    The solution is to check (again) in the OSD menu of the TV to cancel any resizing, any "improvement" effects, and select, if available, a choice such as "PC input" for your hdmi port.

    Some Sony TV have an option looking  like "display all pixels".

    Some hdmi ports on your TV may have different features than others.

    And then, or before, apply the "customized resolution" workaround.

  • 10. Re: HDMI poor quality displaying text compared to DVI
    yudonglei16 Community Member
    Currently Being Moderated

    I've tried another lcd tv of samsung which could disable all pre-processing inside the TV when turn to "pc mode" in OSD of TV. Turn out to be excellent in both text and color. That's exactly why I'm sure that there is no over-scanning via HDMI of SNB(driver of june,2011). Maybe it's the different treatment of TV between GTF and CVT RB rather than HD graphic itself,maybe.

     

     

    The reason why I want HDMI to transmit DVI signal is that: My TV (not samsung) came out in 2009. It does support HDMI but is lack of support of HDMI comes from PC, so there is no switch of pre-processing in OSD. VGA port is normal but not good enough because of noise and multi-ghosting. But I've just tried to connect my desktop PC to my TV via HDMI of nvidia card. Once I disable HDMI audio in nvidia display control panel(no such switch in intel driver) or load the "modified EDID to *inf"(won't work in intel), the nvidia card send out DVI signal (known from OSD of TV showed: "DVI in 1920*1080@60hz") via HDMI-HDMI and texts and colors come back to normal as I wished. That means my TV disables inside pre-processing automatically when in DVI mode of HDMI port.

     

    Because of the compatibility of HDMI and DVI. If HDMI port of HD graphics (SNB mobile) suppport to drive monitors by DVI inputs via HDMI-to-DVI cables or converters. then HD graphic of SNB is able to send out the DVI mode signal via HDMI output definitely from the hardware level.

     

     

     

    I'm still looking for any way to force HD graphic output DVI signal via HDMI-HDMI.

  • 11. Re: HDMI poor quality displaying text compared to DVI
    yf38 Community Member
    Currently Being Moderated

    Hi,

    You are probably right about the last rev. driver, for the first time I saw a different behaviour.

    I installed yesterday the release  ending by 2656, and switched back to HDMI to compare.

    Now it says that I have a digital TV (in fact may HP2159m monitor) with a 1920x1080 59p resolution.

    This 59pHz seems new compared to to 59Hz or 60Hz I had before, and there is also the choice for switching among the various standards proposed by the monitor, 50p, 50i,and so on.

    And there is no initial overscan as before, using "maintain the scale".

     

    You can try to switchoff sound from HDMI using windows sound properties to redirect it to a jack output, but I am not confident this will be understood as "no sound then DVI" instead as "silent sound" by the TV set.

     

    You  can also check if defining a new display with similar characteristics as your TV but  known as "standard monitor" in windows proposed displays, makes a difference.

  • 12. Re: HDMI poor quality displaying text compared to DVI
    yudonglei16 Community Member
    Currently Being Moderated

    I tried to disable HDMI audio in device manager at the very first time.

    It's "silent sound" as you estimated.

    I've found more information that prove intel HD graphics do not care much about custom *inf of TV or monitor driver.

    I've sent an email to confirm it and by the way get some help on this to the technical support since Friday, not replied yet.

    Looks like I'll have to wait the newer drivers of intel (kind of  waste times) .

    or back to the typical VGA port.

     

     

    thanks for reply

  • 13. Re: HDMI poor quality displaying text compared to DVI
    cwatkin Community Member
    Currently Being Moderated

    I just got your reply about the HDMI issue.  I have 4 laptops that don't play nice with this monitor.  All of them are HP's with Intel's latest Sandy Bridge HD video.  Two are Core i5's (identical units), one is a quad Core i7, and the other is a Core i3.  They are all very similar and the same chipset and graphics driver applies to all.  As stated by others, this is an overscan issue when the adapter sees the monitor as a Digital TV.  The custom resolution workaround works for me but reverts back to normal as soon as the computer is rebooted or the screen falls asleep and is woke back up.  This was extremely annoying but I got very fast as changing the resolution.  As stated by others, the text isn't nearly as clear when in the overscan/underscan modes.  It becomes crystal clear when I change the resolution or with the more permanent workaround below.

     

    Anyway, all the adapters in question here are Intel.  None are SNB and none are NVIDIA or ATI based.  This is why I posted my messages to an Intel forum instead of somewhere else.

     

    My current workaround is to use HDMI to DVI adapters and the monitor is no longer seen as a TV so it comes up correctly every time now.  The bad part about this is I now have to use a DVI to HDMI adapter so that I can connect other PC's that use DVI instead of HDMI.  This seems like a lot of work but it functions correctly and there is no issue with text display, etc.  I suspect that an Intel driver update might solve the problem but this works for now and I am not complaining.  I spent hours researching this online and even considered purchasing a new monitor and haven't looked at it since things are working with the cabling adapters.

     

    I think the monitor and adapter simply do not play nice together.  I found someone with the same series of monitor (25 inch version where I have 27 incher) that was having the exact problem on a Dell with the same chipset.  I don't think this is a computer issue.  I think it is related to the adapter/monitor playing well together.

     

    Let me know if this answers any questions.

     

    Conor

  • 14. Re: HDMI poor quality displaying text compared to DVI
    yf38 Community Member
    Currently Being Moderated

    Hi,

    Using custom resolution, try to define two custom resolutions, with the same parameters, except for the frequency, set 59 for one and 60 for the other.

    As I said in the previous post, it seems that the last revision 2656 (win7 x64)  solves this issue (nothing about  in the release notes).

    I installed it yesterday only, and checked this morning, however because I just upgraded the previous revision I am not 100% confident.

     

    For the previous driver updates, each time I updated the driver I had to redefine the custom resolutions to cancel overscan, for 2656 I had no need to do this and there is no more ovescan.

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