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4k by 2k or Quad HD...lots of rumors? thoughts? - Page 111

post #3301 of 3670
Quote:
Originally Posted by Richard Paul View Post

I do not see how motion judder could be caused by the even repetition of frames and that sounds like a myth.
Quote:
Originally Posted by coolscan View Post

Motion Judder comes from low framerate, like 24fps, of that there is no discussion.

No. This is my attempt to show native 24fps with and without 2:2 repeat frame judder. It's an extremely close simulation from my experience. To get 24fps @ 24Hz two frames of every 3 (then one of every 2) were blanked inside of a 60fps source. This 3;2 progression doesn't cause 3:2 type judder because there are no frame repeats or time-shifted frames. To get 24fps @ 48Hz with frame repeats fill in the blanks with duplicates (except one to avoid 3:2 type judder). 2:2 judder is undershot 20% this way I think. In reality it's worse. For 15fps @ 15Hz (labeled 16fps), every 3 of 4 frames of a 60fps source were blanked and that is not a simulation. Included also is 60fps. You guys can make up your own mind.




Edited by borf - 7/8/13 at 8:54pm
post #3302 of 3670
Quote:
Originally Posted by borf View Post

Quote:
Originally Posted by Richard Paul View Post

Here is a link to an article from Ericsson and it covers many of the aspects of UHDTV including motion judder. Ericsson states in their section about frame rates that "motion judder is caused by angular change" and that frame rates of at least 50/60 fps are needed to "minimize motion judder".

That's a good example of how "judder" is used to describe different things:

1) flicker
2) low frame rates
3) pull-down
4) double strobes

Different causes/ different effects here. Would they mean #2 or possibly #1. Unclear. In my experience, "authoritative" sources like John Watkinson (standards conversion) refer to #4.

 

Whoa.

 

#1: Please no.  I'd rename this as "jitter".  I see "flicker" as an issue primarily with the persistence of vision, and flicker is possible when viewing a dead still image at very low rates with a pulse style of light.

 

But absolutely: I've been dying to chime in here during this sword fight of loosely defined terms.  I want people to stay clear of the term Judder if at all possible because when people seem to use it, it causes this odd splintering in the discussion while people talk past each other with meanings.  Oye.  Ban the word already.

post #3303 of 3670
Jitter generally refers to uneven timing when you are talking about audio/video.
Flicker has nothing to do with judder.

Low framerates and repeated frames introduce judder.
Pull-down also introduces judder but that's generally referred to as 3:2 judder or something similar, not just "judder" on its own. And it's really a thing of the past these days.
post #3304 of 3670
Out of curiosity, I did a test of 60fps @ 120Hz on a CRT, to see if it would judder like 30fps @ 60Hz (or 24fps @ 72Hz) does.

Result? No judder. Still looks better than normal LCD.

I don't have a lightboost LCD, but I would guess that 60fps @ 120Hz (with flicker) would look better than 60fps @ 60Hz (without flicker).
post #3305 of 3670
Quote:
Originally Posted by Chronoptimist View Post

Jitter generally refers to uneven timing when you are talking about audio/video.
Flicker has nothing to do with judder.

Low framerates and repeated frames introduce judder.
Pull-down also introduces judder but that's generally referred to as 3:2 judder or something similar, not just "judder" on its own. And it's really a thing of the past these days.

 

"Jitter" refers to audio/video timing??

 

The 3-2 (2-3) pulldown related judder is "Telecine Judder".  From my limited research on it, it's the only consistent usage of the term I've seen when viewing various white papers.  Other than that, it's usually motion blur, or motion handling, or probably a bunch of other colloquialisms.

post #3306 of 3670
Quote:
Originally Posted by Chronoptimist View Post

Flicker has nothing to do with judder.
That said, 2:2 pulldown on CRT's (24fps@48Hz CRT) and impulse displays, exhibit a flickering-edge effect -- double-edge effect that is flickering at half refresh rate. Same effect as videogame 30fps@60Hz.

Also, adding black periods between Hz, can cause the judder to look different (changes the shape of the sawtooth).
For example, 2:2 pulldown on 24fps@48Hz short-strobes such as CRT (symmetric rise-fall sawtooth) has very different-looking judder than 2:2 pulldown on 24fps@48Hz sample-and-hold LCD (asymmetric rise-fall sawtooth).
Quote:
Low framerates and repeated frames introduce judder.
The motion can have different appearances (different sawtooths):
(1) Regular sawtooth, same rise-and-fall (e.g. 2:2 pulldown on CRT, 24fps@48Hz or 30fps@60Hz)
(2) Regular sawtooth, asymmetric rise-and-fall (e.g. playing 24p on sample-and-hold displays)
(3) Varying sawtooth, different peak heights for different frames (e.g. 3:2 pulldown)

For (1) the image bounces back and forth rapidly, catchup and fallback is at the same speed (e.g. symmetric flickering edge effect like playing a videogame 30fps@60Hz CRT). Symmetric rise-fall sawtooth means the image is jumping back and forth between the old and the new position, without any apparent difference in speed how it falls behind versus how it catches up.
For (2) the image slowly falls back and suddenly catches up. More easily seen at 12 frames per second than 24 frames per second, but it's quite apparent the motion is different from (1). Image falls behind gradually (as your eyes continues tracking the motion vector in an analog manner; as your eyes are not digital stepper motors), image instantly catches up to next position as the next frame is shown.
For (3), the catchup is slightly erratic-ish, because of more repeats for some frames than others. (Frame shown 3 times, then 2 times, then 3 times, then 2 times), so a frame is shown for 2/60th of a second, then 3/60th of a second, then 2/60th of a second, then 3/60th of a second. It can look different on strobed versus sample-and-hold displays, but regardless, the erraticness of 3:2 pulldown is apparent on either.

As you turn on/off strobing during 2:2 pulldown for 24fps@48Hz (comparing 48Hz LCD versus 48Hz CRT), the motion vibrating-edge effect changes between (1) and (2) - it's quite obvious that the motion vibrating-edge effect becomes more symmetric versus asymmetric. Some call this vibrating-edge effect as "judder". Some call it "judder" only when it is asymmetric ("judder" looking worse for 24p on 48Hz LCD versus 48Hz CRT). However, "judder" is a loaded word subject to misinterpretation, obviously. What's the definite truth is that the strobing (flicker) vs abscence thereof, changes the motion look enough that people do notice. And even regardless of the display's strobing (or abscence thereof), the back-and-forth vibration of motion, can create the flickering-edge effect that is seen.

Either way, flicker does affect judder/unsmoothness/motion erraticness/motion smoothness/vibrating edge look-and-feel/motion fluidity (choose your favourite word or phrase, depending on how it is defined), indirectly, because of all the above.
Edited by Mark Rejhon - 7/7/13 at 12:20pm
post #3307 of 3670
Quote:
Originally Posted by tgm1024 View Post

"Jitter" refers to audio/video timing??

The 3-2 (2-3) pulldown related judder is "Telecine Judder". From my limited research on it, it's the only consistent usage of the term I've seen when viewing various white papers. Other than that, it's usually motion blur, or motion handling, or probably a bunch of other colloquialisms.
I should have been more clear. Jitter refers to timing variance in the audio or video signals, for example: http://www.benchmarkmedia.com/appnotes-d/jittercu

I was not meaning uneven timing of the frames, such as 3:2 judder.
Quote:
Originally Posted by Mark Rejhon View Post

That said, 2:2 pulldown on CRT's (24fps@48Hz CRT) and impulse displays, exhibit a flickering-edge effect -- double-edge effect that is flickering at half refresh rate. Same effect as videogame 30fps@60Hz.
Yes, I would class this as judder (caused by repeating frames) when you said flicker, I immediately thought of refresh rate flicker. (i.e. CRTs, scanning backlights)
post #3308 of 3670
I have no problem with using the word "judder" if it's understood as "pulldown judder" or "telecine judder". That usage is long-established and the meaning is clear and precise.

I don't like seeing "judder" used for anything else. IMO, it's too conducive to confusion and misunderstanding.
post #3309 of 3670
yeah,There's only so much the human eye can detect.
10.gif
post #3310 of 3670
Quote:
Originally Posted by martaxi View Post

yeah,There's only so much the human eye can detect.
10.gif
It's as easy to see as the difference between 3:2 pulldown and 2:2 pulldown; you just need to know what it looks like side-by-side, in order to recognize the specific looks of motion. People don't pay attention until it is pointed out, then they begin to notice. Same for the other types of motion fluidities -- e.g. 2:2 pulldown (specifically) on impulse-driven displays versus 2:2 pulldown (or any 24p) on sample-and-hold displays.
post #3311 of 3670
How fast does the frame rate have to be so that people will not notice FLICKER? I've heard it said that most people do not notice FLICKER when you get to a frame rate of 72. Is that correct?
post #3312 of 3670
Quote:
Originally Posted by Artwood View Post

How fast does the frame rate have to be so that people will not notice FLICKER? I've heard it said that most people do not notice FLICKER when you get to a frame rate of 72. Is that correct?
It depends on the duty cycle of the display. (how long each frame is held on-screen)
The lower the duty cycle, the more flicker you will see, but the better motion handling is. 72Hz is not nearly enough to be flicker-free on a display with a low duty cycle.
post #3313 of 3670
The short answer for me is that it's acceptable on my crt. 85hz is better. For you it might be a little different. There are lots of factors influencing flicker perception.
post #3314 of 3670
I work on a CRT monitor @ 72 Hz and don't find it uncomfortable. But then again I am from a group of people which barely notices flickering on plasmas.
post #3315 of 3670
I don't remeber if the Intel media box and content service has been mentioned in this thread before, but a rerun can't hurt;
The Upcoming Intel Media Box Could Be the Gateway to 4K

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post #3316 of 3670
Quote:
Originally Posted by Artwood View Post

How fast does the frame rate have to be so that people will not notice FLICKER? I've heard it said that most people do not notice FLICKER when you get to a frame rate of 72. Is that correct?
There are many variables:
-- Duty cycle of flicker. (shorter flashes = easier to see flicker)
-- Brightness of screen.
-- Brightness of ambient environment.
-- Viewing distance.
-- Peripheral vision.
-- Whether you are moving your eyes (e.g. seeing stroboscopic effects)

...There are situations where people cannot see flicker at 48Hz (e.g. darkened movie theater, old fashioned film projector showing each frame twice in 50%-50% duty cycle, using a 180-degree shutter).
...Likewise, there are situations people can see flicker at 100Hz+ (e.g. flicker sensitive people, peripheral vision, short duty cycle with large black period, bright environment)
...And there are people who can see indirect artifacts of 360Hz flicker via fast eye movements (e.g. DLP rainbow artifacts, PWM motion artifacts)
...It does not even end there. Scientific tests have shown 1000Hz flicker can be indirectly detectable via the stroboscopic / phantom array effect. (not as direct flicker)

There is no exact specific value, but 72Hz tended to be a good compromise back in the days of CRT computer monitors. Many also did 85Hz which was even better than 72Hz, and some could even go beyond 120Hz.
Edited by Mark Rejhon - 7/11/13 at 9:59am
post #3317 of 3670
Quote:
Originally Posted by Mark Rejhon View Post

There is no exact specific value, but 72Hz tended to be a good compromise back in the days of CRT computer monitors. Many also did 85Hz which was even better than 72Hz, and some could even go beyond 120Hz.

 

72 used to hurt my eyes after a while.  I was never sure if this was because of a beat-frequency against the ambient CFL's or what.  But it also hurt my eyes (though differently) in a pitch black room, so perhaps not.  85 was rock solid by comparison and did not hurt in either scenario.

 

I had some very dumb older CRT monitors once that had no governance at all on what it would take for a refresh rate.  I drove one at 120 Hz once and some component within it produced a high pitch whine---absolutely no clue what it was.  A co-worker mentioned he did the same thing once and it bricked his monitor, so I put it back down to 85 on mine.

post #3318 of 3670
LG Rolls Out First 55 & 65-inch Ultra HDTVs with LED Local Dimming Backlights

http://hdguru.com/lg-rolls-out-first-55-65-inch-ultra-hdtvs-with-led-local-dimming-backlights/#more-10862

"LGs new LED backlit local dimming 55-inch is called the 55LA9700, the 65-inch is the 65LA9700. They are UPP priced at $5999.99 and 7999.99 respectively.

Both models divide the screen into 144 zones for local dimming. "
post #3319 of 3670
Both models will exhibit significant haloing due to the low contrast of LG's IPS panels.
post #3320 of 3670
Please explain? I was unaware of this...Is it just your opinion or has this been mentioned elsewhere???
post #3321 of 3670
Quote:
Originally Posted by ordo View Post

Please explain? I was unaware of this...Is it just your opinion or has this been mentioned elsewhere???
Local dimming really improves contrast on an LCD display, but it's still an LCD display with a relatively low native contrast ratio. The higher the native contrast ratio, the better the panel is at blocking out light that shouldn't be there. (haloing)

IPS has been stuck around 1,000:1 native contrast for years at this point. Previous LG models that used local dimming exhibited severe haloing, and I wouldn't expect anything different from these.
post #3322 of 3670
Interesting technological development in motion tracking that should fit nicely into the recent discussion that's been going on in this thread.
post #3323 of 3670
This shows how immature is 4K with respect to computer monitors: Currently there are no timing controllers that support 4K@60p. In order to drive the asus/sharp at 4K@60p, two separate TCONs are used. This is why this monitor has the unique capability of supporting dual HDMI. Each HDMI port feeds into its own TCON.
There is no 4K display that can do 60Hz without tiling. 4K@60p TCONs are supposed to start shipping in small amounts this year and in mass quantities in 2014.


The same concerns TVs. Hopefully next year 4K displays will have support for the 60Hz frame rate without tiling.
post #3324 of 3670
4k TV's are not going to support 4k60p until HDMI 2.0 is out. Current HDMI standard only supports up to 4kp30.
post #3325 of 3670
Quote:
Originally Posted by Jeff_DML View Post

4k TV's are not going to support 4k60p until HDMI 2.0 is out. Current HDMI standard only supports up to 4kp30.
And if HDMI 2.0 will only support 2160p at 60Hz, why, when the broadcasters are testing 100/120/150 and 120 fps is already one of the ITU UHDTV standards?
post #3326 of 3670
Quote:
Originally Posted by Joe Bloggs View Post

And if HDMI 2.0 will only support 2160p at 60Hz, why, when the broadcasters are testing 100/120/150 and 120 fps is already one of the ITU UHDTV standards?

All I said was was HDMI 1.4b current supports a max up to 4kp30 and if you want p60 support you need to wait for HDMI2.0. I am not sure what the max frame will be for HDMI2.0.
post #3327 of 3670
This review of Asus 32" 4K monitor shows even better current problems with the 4K. There is in fact no real 4K electronics to drive 4K panels which is amazing taking into account efforts put to make those ultra high-end panels. If everything goes well the 4K electronics might become available mid-2014.
Edited by irkuck - 7/20/13 at 12:38pm
post #3328 of 3670
Quote:
Originally Posted by irkuck View Post

This review of Asus 32" 4K monitor shows even better current problems with the 4K. There is in fact no real 4K electronics to drive 4K panels which is amazing taking into account efforts put to make those ultra high-end panels. If everything goes well the 4K electronics might become available mid-2014.

 

I'm guessing you're mostly talking about the lack of 4Kp60 timing controllers mentioned on page 3?

 

By the way, here's a great quote from that article.  LOL!!

 

From the article above:
By far the worst part about this monitor is the button panel along the right hand side.  It is the mushiest, least user-friendly array of buttons I have ever used, and I don't say that lightly.  ASUS does include a sticker that you can put on the front bezel so you can at least SEE what you are doing, but that doesn't stop the fact that pushing them feels like pressing a breath mint into warm playdough.
post #3329 of 3670
Quote:
Originally Posted by tgm1024 View Post

I'm guessing you're mostly talking about the lack of 4Kp60 timing controllers mentioned on page 3?
By the way, here's a great quote from that article.  LOL!!
By far the worst part about this monitor is the button panel along the right hand side. It is the mushiest, least user-friendly array of buttons I have ever used, and I don't say that lightly. ASUS does include a sticker that you can put on the front bezel so you can at least SEE what you are doing, but that doesn't stop the fact that pushing them feels like pressing a breath mint into warm playdough.

Notice there are also problems with this monitor even when operating in the tile format. It is incredible manufacturers are so shameless to release such unbaked product which is supposed to be ultra-high-end super-professional category and costing loads of money.
post #3330 of 3670
It's a first generation product, and if you need that resolution, you don't have many other options. This is nothing new.
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