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Hey everyone,


Question: I owned an LG 52LD550 LCD TV. After a few days it started buzzing so I took it back. I got a Samsung PN58C550 plasma.


The LG LCD had the 120hz "Tru Motion" thing that makes movies look weird but video games look awesome. You could turn it on and off. Cool.


The Samsung claims 600hz and a 0.001ms (seriously) response time. I know that it's just wordsmithing to make the less-informed go "WOW!!! 600HZ!!! HOLY S**T BUY IT!!!" but I figured that there has to be some degree of truth to the refresh rate of the plasma. There is no "Tru Motion" equivalent and nothing to turn on/off, it is what it is. It also claims that "fast action and sports look razor sharp!"


Here's the thing: not really.


The LCD "Tru Motion" thing really did its job. I could tell because I hated it. I turned it off during everything but video games.


The plasma...not so much. Everything is "motion blurry". ESPECIALLY "fast action and sports". There is a lot of lag and judder and image ghosting (sorry, "judder" is a fairly new word to me and I'm not sure if I'm using it correctly). It is not clear and razor sharp. At all. There are no settings to play with. I thought plasma kicked all ass at the lag-free, judder free, razor sharp so-real-it's-creepy thing.


Clearly I'm missing something here.


And my Blu Ray discs are showing up as "24 hz" and are all ghosting and lagging and motion blurring. My SD DVD's are showing up as 60hz. Again, no settings to play with.


Thoughts? Ideas?


Thanks!
 

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I thought plasmas naturally had that typ of refresh rate but only started to advertise it now because of the LCD 120/240hz marking?
 

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Quote:
Originally Posted by Goatse /forum/post/0


snake oil. Same with 240hz lcd. All they are doing is flashing the backlight fast to make you think there are more frames then there are.

Agree on snake oil but there is no backlight for plasma. It is marketing battle of Hz between the 2 tech and conceptually they are very different. Comparing apple to oranges but easier for J6P to understand heuristically.


Plasma is best for native 24Hz. OP should try using movie mode. Similarly using game mode for gaming. And ask these questions in the TV model thread of this forum. But OP on right track that something is not setup right.
 

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That would be 10 times per frame and all plasmas have that technology. The Y sustain takes a frame and sends it to the X or Z sustain depending on the brand and it gets bounced back and forth 10 times. Making the 60hz picture a so called 600hz picture.
 

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Plasma displays generate a single video frame by compiling together 10 partial frames (subfields). To do this the panel has to be scanned 10 times per frame in order to supply data to all the subpixels for each and every partial frame (subfield).

1 frame = 10 partial frames compiled


in other words:


1 frame = 10 subfields

.

.

60 frames = 600 subfields

.

.

60 frames/second = 600 subfields/second

.

.

60Hz refresh = 600Hz subfield refresh



It is just marketing against LCD high refresh claims because even though the panel does in fact refresh the pixels at 600Hz only 1/10th of that information is full frames. Not to mention the fact that Plasma has operated this way always (Pioneer used 840Hz for 10 years).

Regarding Motion


Subfield refresh does help improve motion but not the same way that LCD interpolation does. The use of weighted subfields to compile a single video frame creates a inherent strobbing effect (flicker). Out of the 10 subfields in each frame only 3 or 4 of them are very bright and the other 6 or 7 are relatively dark. This creates an effective duty cycle of 30-40% (ie - 3 or 4 out of every 10 subfields is bright).


Please see the following graphic which describes this effect of weighted subfields. The height of each bar corresponds to individual brighntess of each of the 10 subfields. The graphic below represents an attempt to reduce flicker by rearranging the subfields.



29-1: 100-Hz Video Upconversion in Plasma Displays

J. J. L. Hoppenbrouwers and R. van Woudenberg

SID Symposium Digest 33 922 (2002)
 

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Quote:
Originally Posted by mirzai_m /forum/post/19615234


The Samsung claims 600hz and a 0.001ms (seriously) response time.

In addition to the post above explaining 600Hz I will add that the .001ms response time claims are also some funky marketing.


The blue phosphor does have response times in this magnitude but the red and green phosphors are 1000 times slower (milliseconds)


Modern Plasma displays (2009-2010) have RG phosphors with ~3-6ms fall time.


They may also be describing the gas discharge response time and not the phosphors themselves.
 

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Its not snake oil, you just dont understand it yet. Pioneer started it, and it makes the picture smoother overall. It does this by dividing up each frame into 10 sections that look like a checkerboard. Each next subfield fills in the checkerboard more and more. This way they can process less at a time and draw motion better. It has absolutely nothing to do with 120hz or 240hz, that stuff is interpolation.
 

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Ya we don't understand it when snakeoil salesman say we can see frames in 0.8ms


However it does feel good to know that we have superman's vision.


As per xrox it reduces the duty cycle to mitigate hold effect, rather than we being able to perceive a 600Hz image.
 

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Quote:
Originally Posted by xrox
...Subfield refresh does help improve motion but not the same way that LCD interpolation does...
Have you come across any papers etc. detailing whether such subfields actually provide ~1080 lines of effective vertical motion resolution? Believe hdguru (hdguru.com) mentioned 600-Hz subfields are responsible for what seems to be a dramatic boost in vertical resolution. ~1080 lines effective motion resolution seems to bypass the Kell factor vertical resolution reduction (~0.7 X line count), and it also exceeds the measured vertical resolutions (static and dynamic) of the mid-90s ATSC-approval committee ( table derived from table 2.3 in the committee's final technical report).


AIUI, this motion vertical resolution test for plasmas involves a special procedure that moves the test camera, supposedly simulating eye movement to track motion details. That seems "convenient" for fantastic test results that differ so radically from early tests (CRT-based), which showed only 400-line motion vertical resolution (interlaced) for 1080i and only 420 lines for 720p (table links above). -- John
 

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Quote:
Originally Posted by John Mason /forum/post/19619240


Have you come across any papers etc. detailing whether such subfields actually provide ~1080 lines of effective vertical motion resolution? Believe hdguru (hdguru.com) mentioned 600-Hz subfields are responsible for what seems to be a dramatic boost in vertical resolution.

From the very beginning of Plasma almost every company employed 480Hz subfield refresh (8 subfields). Pioneer was the exception by using 840Hz (14 subfields).


As I explained in my previous post the subfield refresh creates an effective ~10ms blanking period each frame that gives Plasma its motion performance advantage over conventional LCD.


Now Panasonic and others have moved up to 600Hz (10 subfields). Your question is essentially "does moving from 480Hz to 600Hz account for claimed increases in motion resolution up to 1080p".


Honestly, the only possible way I can conceive this happening is that they have used the extra 2 subfields to extend the blanking period (which I doubt!!). In reality if you read Panasonics papers on the subject they suggest the motion resolution is improved by using faster green and red phosphors along with sub-pixel rendering.
 

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When they were first introducing 600hz, I thought I read somewhere that it was less about motion and more about increasing color gamut/shades of gray. Doing a google search now, I don't find anything on it, did I make this up?
 

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Quote:
Originally Posted by xrox /forum/post/19626220


From the very beginning of Plasma almost every company employed 480Hz subfield refresh (8 subfields). Pioneer was the exception by using 840Hz (14 subfields).


As I explained in my previous post the subfield refresh creates an effective ~10ms blanking period each frame that gives Plasma its motion performance advantage over conventional LCD.


Now Panasonic and others have moved up to 600Hz (10 subfields). Your question is essentially "does moving from 480Hz to 600Hz account for claimed increases in motion resolution up to 1080p".


Honestly, the only possible way I can conceive this happening is that they have used the extra 2 subfields to extend the blanking period (which I doubt!!). In reality if you read Panasonics papers on the subject they suggest the motion resolution is improved by using faster green and red phosphors along with sub-pixel rendering.

Thanks, xrox. Not sure my skepticism about ~1080-line vertical motion resolution came across, then. Was mostly curious about all those ~1080-line test reports for motion, not various subfield rates (480,600, 840 Hz).


What those vertical resolution measurements for plasmas claim, it seems, is that using a CRT for HD viewing (interlaced) means some 400-lines vertical motion resolution for 1080i, or only 420 lines for 720p. Switch to plasma viewing and vertical motion resolution jumps to ~1080 resolvable lines for 1080i converted to 1080p for plasma display. Hard to follow.


Also, having used a high-end 9"-gun CRT RPTV from 2000-2009 for HD, then a 65" 1080p Panny plasma since, can't say vertical resolution--not based on test patterns--seems to have jumped that dramatically, although my generalized Panny review outlined some improved plasma PQ.


This part of my query above cited sources and links to some earlier vertical motion resolution readings:
Quote:
~1080 lines effective motion resolution seems to bypass the Kell factor vertical resolution reduction (~0.7 X line count), and it also exceeds the measured vertical resolutions (static and dynamic) of the mid-90s ATSC-approval committee ( table derived from table 2.3 in the committee's final technical report).



It's not clear whether the test patterns used for all those ~1080-line vertical motion resolution results for plasmas are based on non-sampled (computer, generator) test patterns versus the apparently camera-sampled patterns used for the early ATSC-approval tests (two links just above). However, the special plasma test procedure, detailed in early threads here, uses a camera to simulate eye tracking as I recall. The ATSC final technical report (2nd link) notes they used a rotating (15 rpm) pattern for their 400-line vertical motion resolution reading (1080i), with vertical motion resolution varying directly with the rate of vertical motion. And of course sampled video for HD viewing (cameras, telecines) provides less resolution than non-sampled (computer, generator) patterns because of required Nyquist filtering.
 

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Quote:
Originally Posted by John Mason
Thanks, xrox. Not sure my skepticism about ~1080-line vertical motion resolution came across, then. Was mostly curious about all those ~1080-line test reports for motion, not various subfield rates (480,600, 840 Hz).


What those vertical resolution measurements for plasmas claim, it seems, is that using a CRT for HD viewing (interlaced) means some 400-lines vertical motion resolution for 1080i, or only 420 lines for 720p. Switch to plasma viewing and vertical motion resolution jumps to ~1080 resolvable lines for 1080i converted to 1080p for plasma display. Hard to follow.


Also, having used a high-end 9"-gun CRT RPTV from 2000-2009 for HD, then a 65" 1080p Panny plasma since, can't say vertical resolution--not based on test patterns--seems to have jumped that dramatically, although my generalized Panny review outlined some improved plasma PQ.


This part of my query above cited sources and links to some earlier vertical motion resolution readings:





It's not clear whether the test patterns used for all those ~1080-line vertical motion resolution results for plasmas are based on non-sampled (computer, generator) test patterns versus the apparently camera-sampled patterns used for the early ATSC-approval tests (two links just above). However, the special plasma test procedure, detailed in early threads here, uses a camera to simulate eye tracking as I recall. The ATSC final technical report (2nd link) notes they used a rotating (15 rpm) pattern for their 400-line vertical motion resolution reading (1080i), with vertical motion resolution varying directly with the rate of vertical motion. And of course sampled video for HD viewing (cameras, telecines) provides less resolution than non-sampled (computer, generator) patterns because of required Nyquist filtering.
Hi John,


I can find you a reference as to how Panasonic and others evaluate motion resolution. According to Panasonic automation with a tracking camera is not necessary. They use a scroll burst test pattern. I'll just have to look it up as I forget the title. I actually don't recall them ever evaluating a CRT as reference.
 

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^^^Okay, thanks. xrox. Seems like a scrolling burst pattern would approximate the 15-rpm pattern used by the ATSC test committee. If a camera isn't involved (to simulate eye tracking), then the vast difference between plasma vertical motion resolution claims and the committee results (outlined/linked above) might be the difference between sampled and non-sampled test signals. -- John
 

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Hi John,


I managed to put together a list of journal references you might want to look at. Please PM me if you would like some further information.

Recent:
Advances in Moving Picture Quality of Recent PDPs

IDW 2010

I. Kawahara

Panasonic Plasma Display, Japan

APDC., Japan

Image quality of PDP has been greatly improved in recent years,

including native contrast and moving picture performance. Especially,

moving picture resolution, through elaborate signal processing and fast

phosphors developed for 3D plasma shows stunning superiority also

in 2D mode over other devices. Comparison between latest models is

also covered.

Older

Advantages of Sinusoidal-Burst Based Measurement of Moving Image Performance

The Correlation of MPRT and Moving Picture Resolution with Actually Perceived Moving Image Qualities

Measurement of Moving Picture Resolution for Displays Using Scrolled Sine-Bursts

New Findings on Display Performance in Large-Sized PDP


Edit: Also please take a look at this compilation of test patterns for flat panel analysis:
http://icdm-sid.org/Public/Documents...s/NISTSU01.pdf
 

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Many thanks, xrox, for compiling those references. Wish my SID membership hadn't lapsed, although some full pdfs may be on my '05, '07, '08 special-sections CDROMs or duplicated elsewhere online. I'll browse to attempt confirming whether the many ~1080-line vertical motion resolution measurements relate only to non-sampled test patterns. -- John
 
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