True HDMI signal vs Computer HDMI signal

Hello, I am trying to build an home theater computer, but I am having a problem with the HDMI. I need HDMI because I will be using a TV tuner card (in Japan) and they require HDCP.

The problem is that when I hook up my computer to my TV with HDMI the video is is limited to 1024x768. My tv is a 720p (1366x768) LG 32-lc2d . This tv has a restriction in the manual that says that VGA (D-sub) is limited to 1024x768. I can understand that, but why is HDMI also restricted? If I hook up an Xbox 360, PS3 or any other electronic video equipment by HDMI, I can get full screen with no problems at 720p or 1080i.

My computer is a Japanese Sotec(Onkyo) barebones. It is an unlisted OEM mother board, but it says ASUS on it. It is an NVIDIA 630i/ Geforce 7100 chipset with an HDMI port on the motherboard.

If I go into the Nvidia Control Center and change the resolution to TV: 720p, the image is overscaled( It doesn't all fit on the screen). 480p is the same also.

So the question is: Why does the 720p HDMI signal from my computer differ from the 720p output from say an Xbox 360 or such?

I am thinking of purchasing a new video card. Is there one that will put out a perfect HDMI signal? Is this chipset just too old? I can't output by component because I need HDCP for digital television. (True in Japan, but I don't know about the US)

So how can I fix this problem?

Thank you
5 answers Last reply
More about true hdmi signal computer hdmi signal
  1. need more info here. what graphics card are you running? what conection type are you using (ie an adapter attached to a VGA output for HDMI cable)?

    but it sounds like you need a new card.
  2. I am going off of onboard video, which is an Nvidia 630i / Geforce 7100 chipset. I am running the latest Nvidia drivers (190.38). I am not using any adapters. It is a strait HDMI connection from the Computer to the television.

    This computer is made to be a home theater system. It is in a slim case and has HDMI out on the motherboard. I want to make sure that it is a problem with this chipsets HDMI output. In order to get a new video card, I would have to purchase a new case and power suply, because this is a slim case. So it would be a big investment without even knowing if it will work or not.
  3. mroseneo said:
    Hello, I am trying to build an home theater computer, but I am having a problem with the HDMI. I need HDMI because I will be using a TV tuner card (in Japan) and they require HDCP.

    First off you do not have just hdmi for hdcp support. Dvi supports hdcp just the same as hdmi will. Second point is I would recommend using a stand alone card for your needs. It does not have to be very powerfully if all you are doing is watching tv/blueray. If you are set on using hdmi which is fine you can pick up a standalone card that has hdmi on it from ati.
  4. Thanks for the response. If i use DVI, i won't be able to get sound from the TV. There is no separate sound input when using the HDMI port on the TV.

    I can output 720p to my computer monitor no problem. I am just wondering what is it that differs about the output from a computer and the output from a consumer electronics device that would cause this kind of problem. There must be some sort of signal difference. Perhaps a certain video card will have a more "standard" video signal. What would you recommend for a video card?
  5. I have the same problem... I added an ATI Sapphire HD 4670 graphics card from a new Dell Inspiron 545 to an LG LH20 (26") and the screen is granular... much worse than 21" acer monitor... devices seemingly are reading ATI card... no clue how to fix...
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