Problems with HTPC (IGP & HD4670) and Toshiba TV

[AndyHamp]

Hi,

I have a HTPC built around a Asus M3A78-EM MB and Powercolor HD4670 graphics card.

The Tv is a Toshiba 46RV555DB (UK version) with a 10bit 1080P panel.

There are a number of articles on the net, regarding problems with various HDTV's and ATI cards.

Using the TV's VGA input things work as expected (ie i can display images at the supported resolutions (WXGA, SXGA etc). Ok they're not ful screen, but they are crisp and sharp.

But via the HDMI ports i'm struggling to get anywhere.

I have two options.:

Firstly the motherboard IGP, using the HDMI port or the DVI port. This won't work at any resolution greater than 800x600. This seems to be widely reported, epecially with Tosh TV's.

Secondly the HD4670 card's DVI port. Now on the 4670 i can get a picture on the TV .... BUT it's truely horrible. sending what i think is a 1080P signal it's shown on the TV underscanned (i think this is the right term, but basically it got black borders). Any fonts show are fuzzy (dithered ?)

Anyone got any suggestions how to make this work to give me a true 1080P signal to the TV ... that the TV will accept ?

Cheers ... Andy

[jhhoffma]

You need to be absolutely sure you are matching both the resolution and refresh rate of your vido card with that of your HDTV. Otherwise you will get a converted sample.

Maybe you are outputting a 60hz signal to a 50hz TV?

[QuietOC]

Anyone got any suggestions how to make this work to give me a true 1080P signal to the TV ... that the TV will accept ?

Both AMD and nVidia have overscan options in their drivers.

[AndyHamp]

For the sake of completeness.... i managed to get this working correctly.

Using powerstrip i set the ATI cards output spec to the one stated in the Toshiba manual and the desktop is now full screen.

The horrible fonts were solved by playing with the TV's "sharpness" control. After turning this down everything is crisp. I'm actually impressed how well it now plays SD DVD's. There's almost no difference compared to my expensive Denon player. I may well be replacing it with the HTPC, which makes life so much simpler.

[Nick Geraedts]

I had a similar problem with my HTPC setup (using the onboard ATI 3200 card on my gigabyte board) with a Sharp LCD TV when I was using XP MCE as the OS. However, when I upgraded to Vista, the new drivers managed to get a proper 1:1 pixel mapping out of the box.

What version of Windows are you running?


Also, for the record - the VGA input on most TVs won't allow you to display anything of a "proper" resolution. By proper, I mean either something that is native to the TV, or a resolution that would make sense.

[AndyHamp]

What version of Windows are you running?

Windows XP with the latest 9.1 Catalyst drivers

Also, for the record - the VGA input on most TVs won't allow you to display anything of a "proper" resolution. By proper, I mean either something that is native to the TV, or a resolution that would make sense.

Agreed ... the Toshiba user manual is quiet specific about what resolutions are supported via VGA.


Andy

[NeoteriX]

I had a similar problem with my HTPC setup (using the onboard ATI 3200 card on my gigabyte board) with a Sharp LCD TV when I was using XP MCE as the OS. However, when I upgraded to Vista, the new drivers managed to get a proper 1:1 pixel mapping out of the box.

I too have a Sharp TV (and a 780g gigabyte mobo) and am coping with the lack of 1:1 pixel mapping (burred text when compared with a D-Sub VGA output at the same resolution) -- I was of the understanding that it is a display-side issue, not a function of the graphics card? How are you getting 1:1 pixel mapping through software?

[Nick Geraedts]

I too have a Sharp TV (and a 780g gigabyte mobo) and am coping with the lack of 1:1 pixel mapping (burred text when compared with a D-Sub VGA output at the same resolution) -- I was of the understanding that it is a display-side issue, not a function of the graphics card? How are you getting 1:1 pixel mapping through software?

I'm using HDMI as the connection now, but I had tried VGA back when I was thinking of using an Atom system to play media files. After I found out about the VGA problems, I switched to an HDMI capable system (Gigabyte 780G as well) and things worked much more smoothly.

[NeoteriX]

I'm using HDMI as the connection now, but I had tried VGA back when I was thinking of using an Atom system to play media files. After I found out about the VGA problems, I switched to an HDMI capable system (Gigabyte 780G as well) and things worked much more smoothly.

But you're saying you saw an improvement in the image fidelity over your HDMI connection when you switched from XP to Vista?

To more clearly explain myself, right now I'm running my HTPC over HDMI and I have to put up with blurred text. As far as I've read, it is bc my Sharp TV doesn't support 1:1 pixel mapping over HDMI; I have to revert back to VGA in order for the TV to enable 1:1 pixel mapping. I assumed it was a hardware issue (dependent on the TV), but it gives me new hope if you're saying that it may be remedied by software (as demonstrated by your move from XP to Vista)

[AndyHamp]

To more clearly explain myself, right now I'm running my HTPC over HDMI and I have to put up with blurred text. As far as I've read, it is bc my Sharp TV doesn't support 1:1 pixel mapping over HDMI

On my Toshiba i have the card set to 1920x1080 and it looked truly horrible (even though it's properly calibrated). After playing around for a while i discovered turning the "sharpness" control on the TV right down made the text crisp and sharp rather than fuzzy.

Might not be your issue but worth a try ....

Andy