100hz LCD TV to PC via HDMI

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Infrasound

13 posts

Geek

# 42478 5-Oct-2009 20:29

Hello, I'm in the market to purchase a nice new LCD TV to replace my Dell 2007WFP and have a few questions if someone would be so kind.

As I understand it, LCD TV's produced for the New Zealand market which feature an internal 100hz refresh rate accomplish this by generating "fake" or "artificial" intermediate frames, rather than actually accepting a 100hz source, such as could be provided by a 100hz capable videocard in a PC.

I also believe that we in New Zealand have 100hz rather than 120hz capable LCD TVs due to our using the PAL video format, which refreshes at 50z, rather than NTSC at 60hz.

This then would make me assume that for the 100hz "fake frame" technique to function, the source would need to be a common multiple of 100, which leads me to my main question - what happens when a 100hz LCD TV is connected to a PC providing a 60hz signal?

Since 60hz is no longer a common multiple of 100, do moving images on a 100hz LCD TV connected to a PC stil possess the smoothness associated with 100hz TVs?

Also, if you were playing content on your PC at a strange frame rate, say for example a PC videogame and getting 32fps, how would the 100hz "fake frame" technique deal with this? Would it generate a huge number of intermediate frames to cope?

As you can see I'm quite confused and I'm not even gonna bother putting such a question to a salesman in a shop, as he would be clueless.

Cheers.

buzzy

217 posts

Master Geek

# 261696 6-Oct-2009 14:19

The combination of refresh rates and resolutions depends on the logic inside the TV as well as the display panel capabilities. The panels themselves are usually capable of a lot of different frequencies and resolutions. For example, the 1080P standard specifies a 24Hz refresh rate (among others).

60Hz has long been a common refresh rate for VGA or DVI connections. Most TVs with PC input support 60Hz refresh even though it's not a multiple of the 50Hz PAL signal.

Usually the TV manuals are the best place to look; the PC Input section usually has a matrix of supported resolutions and refresh rates. Pick a TV model and reseller you like, and ask the reseller if you can have a look at the manual to determine the supported PC inputs. If they can't be bothered, shop elsewhere :)

Incidentally, regarding the Frames Per Second (FPS) in a game, that's the number of frames rendered per second and it's independent of the refresh rate. If you're running a 60Hz refresh rate and the game is drawing 32FPS then on average each frame will be displayed twice. The video card will keep sending the same frame every 1/60th of a second until the next frame is rendered, at which point it'll start sending the new frame every 1/60th of a second, until the next frame is rendered, etc (that's a simplification, but it'll do as a rough explanation of how FPS and refresh rates correlate).

Cheers
Buzzy

Infrasound

13 posts

Geek

# 261799 6-Oct-2009 18:33

Hello, thanks for the reply - I'd still like to know if the 100hz motionflow interpolation effect will function on a 60hz signal though.

This could also be an issue when playing back a NTSC (60hz) standard DVD over RCA inputs.

Does anyone actually own one of these 100hz sets and could offer their experiance?