You know phase and frequency are quite convolved Mathematicians will entertain you ad nauseam... Simply put phase error will result from frequency error. The relative phase also 'slips' depending on the freq error.
Originally Posted by Ex-Cyber
When you get rid of the freq and phase error there is nothing to tear apart. Everything is smooth as butter. That includes no visual tricks whatsoever and is also provable to be 'perfect'.
Last edited by vesa; 07-20-2009 at 11:45 AM.
Cool sounding project - I've been looking into getting a decent lcd monitor for some time, but none of the specs I've seen go down to 50Hz.
Originally Posted by vesa
Have you found that it is possible to underclock LCDs?
I think the some V(YXZ)GA spec starts officially from 56 Hz. It is easy to test and makes no damage in modern monitors. I've also noticed that some panel sizes don't usually support 50 Hz. Benq had in their P-series a monitor that started from 24 Hz. I guess every 'pro' stuff starts from 24 Hz. http://www.benq.com/products/LCD/?pr...specifications at least says 50 Hz. I'm no way affiliated with Benq and currently run ViewSonic VP171s (that I specifically bought because of 50 Hz and paid some premium back then) and LG L1950S. LG only does down to 60 Hz, but WS 48 Hz too, so kind of underclocking, but that much tolerance should be there anyway.
Originally Posted by legume
48, 50 and 60 Hz would be everything I need.
The ideal tear-free solution is a CRT monitor that supports run at 120Hz. 24p, 30p, 60i and 60p display perfectly, without touching timings or changing modes. You still have to drop to 100Hz for 25/50p, but such material is rare so it's not a problem.
That said, almost everyone has switched to TFTs nowadays which tend to lock at 60Hz. A few can do 72Hz or 48Hz, but that's relatively rare (plus you have to add custom timings because these modes are (usually) not reported automatically.
Bottom line: for perfect video, grab a CRT while you still can, or connect to an external TV that supports 24p-60p natively.
Lots of TFT can use 75 Hz too - even if they don't advertise that. One older FSC TFT even uses 75 Hz as default DCC setting. Instead of 48 you could use 72.
Games, mostly. Right now a PC that can put out 200fps on max settings for most current games is within the budget of even normal people. I've seen TV ads for LCD televisions that already go that high, so apparently there is a market for this sort of thing.
Originally Posted by bridgman
Thanks for the links - it's good to know there is hope, but it does seem like a bit hit or miss, what with some modern monitors seeming to have their own scalers & input lag etc. I saw a review site which claimed some ran at their own internal rate whatever the mode (and people couldn't get their games to vsync on them).
I've seen 75Hz on VGA input frequently, but I also read on one site that when they tested the monitor was just dropping frames to achieve this. I am not saying they all do this of course.
I have a CRT so can do SD 50i stuff with my monitor @50 or 100Hz.
Perceptually there is a difference, only 50Hz is correct. Not that easy to notice on normal video, but if you look at a worst case test stream like a fast white pendulum on black @50fps you will not perceive it as solid with monitor @100Hz because of the two flashes per frame.
I can also see this effect by say forcing a game fps to cap at 1/2 monitor refreshrate.
Mordern high end TVs with high refresh rates actually interpolate intermediate frames to avoid motion blur/judder.
In practice I still use 100Hz as I perceive flicker too much @50 and current wait for vline vsync tends to fall apart when fps=refresh (and it's worse than just the odd skip/double with mplayer)
Well INTERNALLY those tvs provide 100/200 hz. But i highly doubt that they provide those modes to direct use. Do you know how rare are 120 Hz capable TFT for use with Nvidia shutter glasses?
BlackStar, yes that kind of CRT would be nice, but 1080p @ 120 Hz means 560 MHz pixel clock. That's nothing cheap or common. One also has to put video DACs right at the CRT gates to preserve needed analog signal bandwidth. I once had ECP 3100 tube projector running 1280x960 @ 50 Hz and was going to put it in use as 100 Hz interlaced system. The graphics card/drivers didn't support interlacing then and would also need frame locking, so it was forgotten. Nothing beats the quality of good CRT, but good ones cost too much.
Kano, 72 Hz would be fine if link bandwidth allows. My understanding is that 1920x1200 @ 60Hz is the limit for single link DVI. On smaller resolution it is workable though.
Ant P., I doubt that much over 120 Hz is of any real value visually and it includes interleaved 3D stereo. That's up to debate and rigorous testing of course
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