LCD Screen Refresh Rates – More snake oil!!

LCD frame refresh rates get bumped up. Why??

What’s with all the hype regarding those higher refresh rates for LCD screens that are being pumped up beyond 60 Hz these days as the answer to eliminating those pesky video smears or blurs that occur in scenes that have high intra frame to frame motion?  Rates like 120Hz, 240Hz and now being extolled 480Hz. Since when is higher better in this case?

Let’s first take a look at why this phenomenom has come about. It looks like the LCD HD video panel has a problem with refreshing its individual color pixel elements in the panel array, that if too slow the next frame paint will show a blur or a smearing effect in those video frames that have high intra pixel to pixel changes between them — due to residual voltage charge still being resident in the pixel cells.  So slow pixels even with a 16.7ms refresh rate cause a problem.  Then, let’s bring on the 5ms, 2ms and 1ms vertical refresh rates. This in itself should be enough to address the problem, but no lets add some neat engineering tricks to ‘enhance’ the fix.

The ‘enhanced’ fix is to decrease the pixel well charge/discharge times so that one or more frame repeats can be done within the 60Hz constraint without any residual pixel charge still resident.  Keep in mind the original video source material is still only the 60hz field rate (24hz for film telecined material to 30fps). This is a LCD panel problem not a video content problem.

Did the directors of cinema movies miss something in film school so that their prime medium running at 24fps has a problem?  Ok, sure it’s limiting by todays standards and has a history, but workarounds in terms of applying creative production techniques has been leveraged to the benefit of the film maker.  The problem is the conversion of film and video being played back on an LCD screen. Again, an LCD technology deficiency. Not a medium problem.

Some manufacturers like Samsung and SONY have introduced anti-blur and anti-judder video processors to work in conjunction with the higher frame rates. Though much to their credit for great video processing technology, the net result doesn’t appear to bear the fruit expected. The technology creates new frames by interpolating existing and quasi inter frame information. In other words building new frames with a best guess.  In some cases the output video looks a little unreal when compared to the ‘slower’ refresh rate.

Don’t get me wrong I love highly creative application engineering, but at times it’s time to put down the pencils and see the forest for the trees.  Been there done that.  Lessons learned.  It’s disheartening to read the blogs and forums that perpetuate the technology fix without presenting more than the limited critical commentary out there now. The fast frame fresh rate technology appears to have a momentum all its own in an effort to troll for consumers that perceive value in higher and faster spec numbers.  After all higher and faster is better right!

Go with a quality name brand LCD or plasma panel that have the features that work for you and forget the snake oil of gizzilion contrast ratios, warp speed refresh rates and billions in Deep Color and save your self some money.

Oh yeah, the next fad, 3D TV, don’t get sucked into that vortex.  How about real 3D.  That has a real wow factor and no glasses to boot.

Ok, my next commentary article coming soon.