Difference Between 50 Hz And 60 Hz On Lcds

[llsTixll]

Hey guys

Does a 50 Hz and 60 Hz display output (either composite or component) look different on a LCD TV?

For example, I currently have a cheap SD tuner box (DGTEC) that only has composite out and I'm pretty sure it only outputs in 50Hz. Will this look crap on say a 32" LCD TV or will it look ok?

Maybe some theory into the 50 Hz/60 Hz technologies may help me out.

Cheers

[AndrewWilliams]

Most LCDs should support 50 & 60Hz these days. That said, a LOT of PC monitors still have a minimum refresh rate of 56Hz which is a bit annoying for Aussies wanting to watch TV with perfect smoothness on their PC.

I remember some LG & NEC plasmas a few years ago (among others) which didn't support 50Hz. They didn't synchronize the signal with the refresh rate which resulted in 'tearing' or 'shearing' Some people didn't even notice it but it's one of those things that once you see it, it drives you 'round the bend.

[llsTixll]

Ok, I think I get it.

If you have a PAL DVD (50Hz) and it is being displayed at 60Hz, then it is sort of 'accelerated' so frames are lost and looks stuttered.

So in terms of HD, if you're watching mostly Australian content (PAL) on a HD panel (LCD or plasma) then 50Hz is the optimum. But if you're watching it on a normal CRT, then 60Hz is better due to the way CRT refreshes the screen. Yes?

And if I plug my SD STB into an LCD via composite (and it only outputs at 50Hz) then that should be fine? (Except the fact that's it's composite and not as good as component).

Also, why does an LCD monitor via VGA look clearer using 75 Hz rather than 60 Hz in Windows XP?

And finally, if 50Hz is PAL, then why are some XBOX360 games in 60Hz only. Does that mean the XBOX360 has to be in 60Hz to play them? But if the 360 is in 60Hz and you play a PAL DVD, then won't you get the same stuttering?

Thanks

[llsTixll]

Anyone?

[Owen]

If you have a PAL DVD (50Hz) and it is being displayed at 60Hz, then it is sort of 'accelerated' so frames are lost and looks stuttered.

Frames have to be repeated to covert 50 to 60, resulting is stutter.

So in terms of HD, if you're watching mostly Australian content (PAL) on a HD panel (LCD or plasma) then 50Hz is the optimum. But if you're watching it on a normal CRT, then 60Hz is better due to the way CRT refreshes the screen. Yes?

Sort of, a CRT will have the same stutter problem if run at 60Hz to display 50Hz video, but there is also the issue of flicker on a CRT.

For flicker reasons CRT’s are usually operated at 75 or 100Hz. (1.5 or 2 times 50Hz)

And if I plug my SD STB into an LCD via composite (and it only outputs at 50Hz) then that should be fine? (Except the fact that's it's composite and not as good as component).

Some LCD’s operate at 60Hz internally only and will suffer stutter.

Also, why does an LCD monitor via VGA look clearer using 75 Hz rather than 60 Hz in Windows XP?

That should not be. Must be something specific to that display.

And finally, if 50Hz is PAL, then why are some XBOX360 games in 60Hz only. Does that mean the XBOX360 has to be in 60Hz to play them? But if the 360 is in 60Hz and you play a PAL DVD, then won't you get the same stuttering?

Virtually all HD displays sold here will accept 50Hz and 60Hz input so the Xbox should always display a picture, but if it is outputting 60Hz, 50Hz video will stutter.

Film source (24Hz) video stutters on a 60Hz display for the same reason.

Film sourced content like PAL DVD’s are normally sped up 4% to 25Hz for display on PAL 50Hz systems, resulting in no stutter.