120mhz technology in plasmas?- help please!! (1 Viewer)

[mastermaybe]

hi e-one,
does it exist? I only ask as it seems to be vey effective in a lot of lcd models I have considered (namely the xbr4, which I am strongly considering purchasing).

It is my impression that plasmas are inherently better at handling motion, but wouldnt they (plasma's) benefit from this technology as well? Perhaps it is just my ignorance regarding plasma technology?

I've really only considered lcd to this point as the majority of plasmas I've seen personally seem exceptionally prone to glare from light sources (even though with "glare reducing coatings"), and I have a plentitude of natural and artificial light in my living room.

thanks for the help,
james

 

[Allan Jayne]

72 frames per second is occasionally used at the video screen instead of 60 fps so that film source (24 fps) can have equal time (3 screen flashes per film frame) instead of alternating 3 flashes, 2 flashes, 3 flashes, 2 flashes. But the video display must "change gears" back to 60 fps for live video which is 60 frames per second (or 60 half frames per second for interlaced video). There are probably some plasmas today that operate at 72 fps, which you don't notice (other than slightly less flicker) since the input is the same old 60 fps progressive scan or 30 fps interlaced video.

120 fps is a common denominator so the video screen can behave the same way for both film source and live video source.

The success of 120 fps is having 24 fps or 120 fps input, or having a dissector (more correctly an inverse telecine frame rate scaler) in the TV that identifies film source within the 60 fps or 60 field per second input format and picks out each of the 24 film frames per second content wise and gives them equal time on the screen, five flashes per film frame. Incorrect dissection or picking out will nullify the advantage of 120 fps, namely some film frames will get more screen time than others. There is already a 24 fps hi-def output standard for DVD players but I don't know of a 120 fps output standard, HDMI or otherwise.

Still better results can be had with 72 or 120 fps video if intervening frames can be synthesized from 24 fps film source literally coming up with 48 fps video. So far there are no inexpensive methods other than fading/blending, namely frame 1-1/2 is the average of frame 1 and frame 2.

An alternative reason for 120 fps for LCD's could be nothing more than a dirty secret. LCD has a slower response time resulting in such things as smeared motion. It is possible that 120 fps on the LCD consists of alternating video frames (60 per second) and black frames, the latter making the LCD turn opaque faster thus making the light output decay faster and reducing response time smearing. For 24 fps film source there could be three frame-times of video and two frame times of black for each film frame. When the frames are flashed on the screen fast enough, black gaps between frames are not noticed.

Video hints: http://members.aol.com/ajaynejr/video.htm

 

[Kevin C Brown]

I don't know of any plasmas that offer 120Hz. For the very reason you mention: plasmas simply do not have the problems with motion that LCDs do. That is it's sole function for LCD right now: to minimize motion blur.

LCDs are indeed better for rooms with a lot of ambient light. But yet the fact remains that plasmas typically have better blacks, contrast, and color rendition, giving a better representation of the movie going experience than LCD. LCDs are getting better, but you pay for it. The Sony XBR's and the Sharp D92's among others are approaching the best blacks that plasma has to offer. But, go ahead and compare prices between Panasonic and Pioneer plasmas vs those two at the same size. Plasma is a lot cheaper.