VGA vs HDMI vs Refresh Rates

[RetroZA]

TV-Server Version: TV-Server 1.0
MediaPortal Version: MediaPortal 1.0 RC3
MediaPortal Skin: Monochrome 2.2
Windows Version: XP MCE SP2
CPU Type: Intel 2.4ghz
HDD: 20gig IDE & 500gig SATA
Memory: 1GB DDR400
Motherboard: Intel865G/ICH5
Video Card: Geforce FX5200
Video Card Driver: Nvidia 175.19
Sound Card: Realtek ALC650
Sound Card AC3: Optical S/PDIF out
Sound Card Driver: Realtek Avance AC97
MPEG2 Video Codec: ffdshow
MPEG2 Audio Codec: ffdshow
h.264 Video Codec: CoreAVC
HTPC Case: Aopen XC Cube EY65
Power Supply: 220W
Remote: Microsoft MCE
TV: Sansui 40" LCD (720p)
TV - HTPC Connection: VGA

Ok, a couple of different issues. I recently installed a new graphics card, only to remove it again because it was too noisy. When I installed the old graphics card again I also updated the drivers. After that the video quality with MP's internal player was horrible. Lots of lines across the screen and flickering. It still played fine with Windows Media Player and Media Player Classic. After a bit of searching on the forum, I saw someone suggesting to rather use older drivers. So I uninstalled the new drivers and installed the old ones (175.19) again. Perfect! Well almost...

When I have the refresh rate on 60mhz, everything plays fine, as soon as I make it higher, I get scan lines and a flickering screen again. I'm happy to stay on 60, but everything else in Windows (text etc.) are all scrambled. You can still read the text, but it's not as clear as it should be. When I up the refresh rate, I get perfect quality, but then the problem with the player again.

So yesterday I decided to try to output to the HDMI port on my LCD, from DVI on my pc. When I'm using the VGA cable, I run the resolution on 1360 x 768. On HDMI it picks up the resolution as 1280 x 720. Which is fine, but the desktop area is too big for the screen. You have to scroll to reach the end of the desktop area. There are options with the Nvidia Control Panel to fix it, but I can't get it perfectly right. Is there an easier way to fix this? And is it in any way better to use HDMI instead of VGA?

[SEALen]

Can't you output 1366x768 on the DVI? Or maybe 1360x768? If not I guess your LCD don't have 1:1 pixelmapping on the HDMI port (just like mine) so I always use the VGA port since it's 1:1 pixelmaped at 1360x768.

The big difference between VGA and HDMI is the quality of the cable you need to use. A crap $5 VGA cable will ruin your picture at these high resolutions but a $5 HDMI cable will probably work nicely since it's digital. If you got a good VGA cable I doubt you can see much difference between a VGA fed and a HDMI fed screen at 1366x768.

[mikildemion]

On the refresh rate, all LCD's run 60, don't bother changing it.

For the resolution, it sounds like your LCD's native resolution is 1280x720 anything larger than that will cause it to scroll. This is the nature of LCD's. they have a fixed size. Unlike CRT's where they will scale (up to a max). I would suggest using the HDMI, set the resolution to 1280x720 and then is you need to use the adjust display wizard (in nvidia control panel) or you can do a custom resolution to fit your TV if you need to. But 1280x720 is considered HD, so your not loosing much from your other resolution. Plus HDMI will give a clearer picture over VGA or TV out, due to keeping the signal digital from your computer to the display.

[5Hundred]

@milkidemion 60hz is not preferred for PAL countries, we use 50HZ, so you're first sentence is incorrect

[RetroZA]

Originally Posted by mikildemion

On the refresh rate, all LCD's run 60, don't bother changing it.

For the resolution, it sounds like your LCD's native resolution is 1280x720 anything larger than that will cause it to scroll. This is the nature of LCD's. they have a fixed size. Unlike CRT's where they will scale (up to a max). I would suggest using the HDMI, set the resolution to 1280x720 and then is you need to use the adjust display wizard (in nvidia control panel) or you can do a custom resolution to fit your TV if you need to. But 1280x720 is considered HD, so your not loosing much from your other resolution. Plus HDMI will give a clearer picture over VGA or TV out, due to keeping the signal digital from your computer to the display.

Well, like I said, 60 is fine for watching the movies, it's just the text in Windows that's not clear.

In the manual for the LCD tv it shows the resolution as 1360 x 768 (or 1366). So I'm guessing it's better to run it at this resolution?

[SEALen]

Yes, you probably have a native resolution of 1366x768 but that resolution is not in the VGA standard so many LCDs only allow 1360x768 that is in the VGA standard. However many LCDs also don't have 1:1 pixelmapping on the HDMI port only allowing 720p or having some sort of overscan on the input.

5Hundred: All LCDs still run 60Hz refresh rate even if PAL countries run 50Hz in the power socket.

[5Hundred]

Sealen, you dont know what you're talking about. refresh rate and the frequency of the AC supply are totally unrelated. In the UK, NZ and many other countries our PAL tv's operate at a 50hz refresh rate.

[Slurm]

Just to clear it up:

PAL uses 50fps (even and odd half-frames, a total of 25 full frames), so it would be best to display it at 50Hz.

VGA (Sub-D) on LCDs only works at 60Hz (some LCDs accept different Refresh Rates but I haven't heard of one accepting 50Hz).

To display PAL content the way it should be displayed you need a multiple of 25. This can be done through HDMI or with less picture quality through RCA connector, S-Video or Component on a PAL capable TV.

For 24fps content (mostly HD content from Blu Ray or HD-DVD) it's the same - you need a multiple of 24 to view it stutterfree - but you can also do a pulldown to display it on 60Hz Devices (though there is a slight stutter on horizontal scrolls).

You can display any content on any Refresh Rate but if fps and RR don't match you will see more or less stutter.

Oh, and RR and AC supply are totally unrelated as 5Hundred already said, but there is a historical connection between them.

[5Hundred]

Good last point Slurm, i'd never connected the two but of course at some point in the past the refresh rate would have been determined by the AC supply. Presumably thats why NTSC and PAL have the refresh rates that they do.

Thanks for the info

[SEALen]

Ahh well, Slurm did put the whole thing correct above. LCDs run at 60Hz refresh rate no matter what TV system you are using. The electronics in the screen or in the computer do some magic to get it to look right.