No 1080p via 15m HDMI?

[flarkit]

Yesterday I hooked up the PC to a new 24" LCD via a 15m HDMI cable, using a DVI-to-HDMI adapter.

It wouldn't display 1920x1080, but works if I drop the resolution (for an 8800GT) to 1280x720, with the signal format set to 720p. Anything above that and the LCD only detects a horizontal frequency of 33.3KHz instead of 66.7KHz.

It's slightly irritating that I can't use the full potential of the LCD with a long cable which I was told should be fine and paid R450 for.

I tried using a 5m HDMI cable which seems to be the same thickness (24AWG I hope!) and was only able to get the resolution up to 1768x992 and it seems sharper at 1680x1050.

The next thing will be to try an HDMI extender like this: http://www.hdcabling.co.za/hdmi-cab...o-hdmi-cable-signal-up-to-30-meters-p-78.html

 

[I am Penguin]

Where did you get the cable from, what brand is it? I run a 15 meter cable between PS3 and LCD at 1080p no problem. Could it not be the display card rather than the cable? Check the HDMI specs.

 

[flarkit]

Where did you get the cable from, what brand is it? I run a 15 meter cable between PS3 and LCD at 1080p no problem. Could it not be the display card rather than the cable? Check the HDMI specs.

I bought it from Superiorvision. It's not branded. I suspect it might be that the 8800GT has an issue, but then I'd expect the same output on both the 15m and the 5m cable. The card has VGA, DVI and S-video outs. I'm using a DVi-to-HDMI adapter

 

[quovadis]

I'm using a DVi-to-HDMI adapter

That could be your problem - the adapter might not support 1080p

 

[I am Penguin]

I bought it from Superiorvision. It's not branded. I suspect it might be that the 8800GT has an issue, but then I'd expect the same output on both the 15m and the 5m cable. The card has VGA, DVI and S-video outs. I'm using a DVi-to-HDMI adapter

Maybe get a GPU with confirmed HDMI HDCP capability.

 

[flarkit]

An interesting discovery, after following this: http://www.avforums.com/forums/lcd-...dvi-hdmi-issue-le40m87bdx-blu-ray-8600gt.html

Enter nVidia Control Panel, Manage custom resolutions and click "Create".
(Custom display mode values)
Horizontal desktop pixels: 1920
Vertical desktop lines: 1080
GDI Refresh rate: 24
Bits per pixel: 32
(Back-end parameters)
Timing standard: Manual
Horizontal front porch: 638
Vertical front porch: 4
Active horizontal pixels: 1920
Active vertical pixels: 1080
Horizontal total: 2750
Vertical total: 1125
Horizontal sync width: 44
Vertical sync width: 5
Horizontal sync polarity: +
Vertical sync polarity: +

Horizontal scan rate should be: 27.00 (does not seem to matter if not displayed)
Pixel clock should be: 74.2500

Now click "Test".

It should display 1920x1080 @24Hz (press the INFO button on the TV remote to check).

If it does, click "Yes".

You should now have 24Hz as a Refresh rate option when you cick on "Change resolution" on the left of the window.

This did not work for me properly the first time but did after a reboot.

Now my windows desktop displays in 1920x1080 @24Hz.

By adding a custom resolution for 1920x1080 @24Hz, I have a desktop on the screen. It appears to insist on Interlaced (which I assume implies 1080i), instead of Progressive (or 1080p). The text and contents of windows are a little fuzzy and not perfectly sharp though. However, fullscreen video seems to be exactly the same as when played at 1280x720 (720p), which is stable and clear. So far I've only used the basic settings, without adding the so-called "back-end parameters" yet.

 

[I am Penguin]

An interesting discovery, after following this: http://www.avforums.com/forums/lcd-...dvi-hdmi-issue-le40m87bdx-blu-ray-8600gt.html



By adding a custom resolution for 1920x1080 @24Hz, I have a desktop on the screen. It appears to insist on Interlaced (which I assume implies 1080i), instead of Progressive (or 1080p). The text and contents of windows are a little fuzzy and not perfectly sharp though. However, fullscreen video seems to be exactly the same as when played at 1280x720 (720p), which is stable and clear. So far I've only used the basic settings, without adding the so-called "back-end parameters" yet.

As expected then I think the card is the main issue and not the cable.