PC --> TH-42PX over DVI-HDMI, resolution settings?

globalist

Novice Member
Hi all,

I just bought the Panasonic TH-42PV45EH (euro version) plasma and all is uber great but one thing- I have my PC hooked up over DVI-HDMI (input 1) cable and no matter what I do I always end up with small black borders around the plasma screen.

The only way to get rid of them is to set the secondary monitor (which is the Panny) resolution to 1920x1080 but then I lose some portion of the picture on the left and right sides of the screen...

It looks to me as if the reported res of (say) 1280x720 were displayed more like 1274x714 on the plasme screen and the rest is filled with black...

Anyone able to explain to me what I'm doing wrong?

How do you guys hook up your PC to your plasma (1024x768 native res) over HDMI and what res are you using?
 

Gussie

Active Member
Hi all,

I just bought the Panasonic TH-42PV45EH (euro version) plasma and all is uber great but one thing- I have my PC hooked up over DVI-HDMI (input 1) cable and no matter what I do I always end up with small black borders around the plasma screen.

The only way to get rid of them is to set the secondary monitor (which is the Panny) resolution to 1920x1080 but then I lose some portion of the picture on the left and right sides of the screen...

It looks to me as if the reported res of (say) 1280x720 were displayed more like 1274x714 on the plasme screen and the rest is filled with black...

Anyone able to explain to me what I'm doing wrong?

How do you guys hook up your PC to your plasma (1024x768 native res) over HDMI and what res are you using?

It's not easy with the PX/PV TVs.

With acknowledgement to poster autosapien - he explained it very well ...

The VGA input can accept and display the native resolution of the plasma, ie. 1024 x 768 pixels. This means when you set your PC/Mac desktop to 1024 x 768, every desktop pixel is perfectly mapped to every screen pixel and the internal scaler of the screen is disabled. The result is a razor sharp desktop and text. So whatever video content you watch, it only needs to be scaled once, eg. PAL video is scaled by the PC/Mac from 720 x 576 to 1024 x 768 and sent to the display where it is displayed at 1024 x 768.

The HDMI (or Component) input cannot accept the native resolution of the display. It can only accept SD and HD video resolutions (ie 1280 x 720, 1920 x 1080) as opposed to PC resolutions such as 1024 x 768. So if you set your desktop to one of these supported video resolutions (say 1280 x 720), the PC/Mac will scale PAL video from 720 x 576 to 1280 x 720 and send that to the display. The display's internal scaler will then rescale the 1280 x 720 to the screen's native resolution of 1024 x 768, resulting in two scaling operations.

The only option to avoid this double-scaling via the HDMI input would be to set the desktop to 720 x 576. However, many cards may not support this resolution, and of course it's not HD!

In short, the scaling operations are as follows:

PAL video via VGA = 720 x 576 -> 1024 x 768
PAL video via HDMI = 720 x 576 -> 1280 x 720 (or 1920 x 1080) -> 1024 x 768

To make matters worse - Panasonic PX/PV series TVs overscan badly on HDMI and Component - I gave up with HDMI and Component from my HTPC and just used VGA instead - relying on a single re-scaling done by my PC graphics card - not ideal!

If you want better PC functionality - use VGA or if going HTPC - go for a panel solution or get a 1080p TV.

Gussie :)
 

globalist

Novice Member
The HDMI (or Component) input cannot accept the native resolution of the display. It can only accept SD and HD video resolutions (ie 1280 x 720, 1920 x 1080) as opposed to PC resolutions such as 1024 x 768.

Thanks for the thorough explanation, but it doesn't quite explain the 3cm black borders around my display does it? Plus I'm quite sure I was able to set the secondary desktop res to 1024x768 when I was tinkering with this last night...

Still a little baffled.
 

J_C_COOL

Active Member
Globalist did you sort this out at all?
I've just bought an HTPC for my px70 that arrives next week and am now worried that my x264 films are gonna look rubbish... :eek:
 

globalist

Novice Member
Globalist did you sort this out at all?
I've just bought an HTPC for my px70 that arrives next week and am now worried that my x264 films are gonna look rubbish... :eek:

Why yes, I had to set a "custom" resolution in Catalyst Control Center (my vid card is ATI X1950Pro) wherein the black borders would no more show up on the TV.

It's 1216x684 for me, but your mileage may vary. Either way the TV seems to be doing perfect pixelmapping at this res (tested with the Monitor Test utility) and I'm a happy camper now. x264 looks fabulous too :D
 

EmThor

Standard Member
You have the 42px70?

I've heard from a german forum, that from a laptop with ATI, you can use 1280x960, with minimal overscan and good picture quality via VGA!!
 

CHFels

Active Member
Why yes, I had to set a "custom" resolution in Catalyst Control Center (my vid card is ATI X1950Pro) wherein the black borders would no more show up on the TV.

It's 1216x684 for me, but your mileage may vary. Either way the TV seems to be doing perfect pixelmapping at this res (tested with the Monitor Test utility) and I'm a happy camper now. x264 looks fabulous too :D

Glad to hear it's working well:smashin: , since I may be doing the same soon (on a 70 or 700). But it can't be doing perfect pixelmapping if it's scaling 1216 down to 1024 and 684 up to 768, can it? Or does this magic number combo somehow fake perfect pixelmapping? The 684-to-768 part would have to add resolution, which I thought was not possible. :confused:

CHFels
 

EmThor

Standard Member
Here are the settings the mate said on the german forum: 1280x768 60Hz, with ati 1700, asus laptop, so its not the 1280x960 as I said wrong before.

maybe worth a try, he said the picture is sharp enough!
 

globalist

Novice Member
OK now that I've got an nvidia 8800gts card I cannot for the life of me figure out how to get the same perfect 1:1 display out of the card into my Panny. I simply cannot create the custom 1216x684 resolution as the test of that always fails.

Any ideas anyone?

Edit: I created the resolution and I can adjust the overscan using a registry tweak by nvidia but I can't seem to get the same sort of pixelmapping I got with my radeon... hmm.
 

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