"The Big Judder Problem and the Overhyping of 24p"

Do not forget that HTPC user's can use the Reclock ultility to speed-up 24p content to play at 25p (effectively 2:2 pulldown at 50Hz)................thx Nielo!

This is my perfected method for watching HD-DVD and US TV rips on my setup. I do not need Reclock for PAL sourced material, but use it anyway, as it gives more accurate PC clock timings.

(I use MPC-HC in renderless EVR mode for vsync correction, in case anyone wants to try it)

Clearly not an ideal solution as the pitch has to be altered to avoid chipmunk type voices (roughly 8% faster.....25/24), and not applicable to consumer equipment. But a better compromise for me. If my TV displayed 24p or 48p natively (like some CRT projectors), then that would be the way to go.
 
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Thanks

With the X360, it's a bit more complected as 99% of the games have artificial motion blur enabled by default.

Also, majority of X360 games are rendered at 30fps. So the motion blur produced by games and displays actually help to keep the frame transitions appearing smooth/soft. If you remove the blur, motion will appear harsh and it'll be very hard to play.

Trust me, I know. I've tested few games on my bro's CRT monitor and I found it hard to keep track due to the harsh motion. However, this is not a problem with interlaced CRT.

PS: In dark scenes/areas, the motion will appear smooth but smeared. That's due to the pixel response time, which is still an issue.

That's a really interesting post.

I still haven't grasped the concept between hard and soft motion. And as you have stated, hard motion would make the game hard to play... I think I would need to see the two side by side to get a clearer picture in my head.

What you mentioned about pixel response time and dark scenes is really interesting!! Let me explain: Many people and myself including, have mentioned they see really prominent smearing when playing either Xbox or PS3 on the Samsung series 6 LCD tv. This smearing only happens with dark areas, but it's absolutely shocking when it happens. I don't understand how it can be response related, as the TV has a stated response time of 6ms, where with this dark smearing, you can see the pixel trail / remains for nearly 1000ms! How is this possible?
 
BTW, when you change the motionflow to low, mid and high, does the screen turn black for less than a sec?

If it doesn't, I think the display frequencies are fixed. So all 50Hz contents are displayed at 100Hz while 24 and 60Hz contents are displayed at 120Hz via pull-down.

This means the level of motionflow simply determines the level of frame interpolation without changing the panel's operating frequency.

No there is no change-of-display-frequency black screen. On the Sony there are 2 settings - standard and high. So yes you must be right about everything getting displayed at the higher frequencies as a matter of course and motionflow just controls the degree of interpolation.

I've learnt a lot today - thanks :smashin:
 
Do not forget that HTPC user's can use the Reclock ultility to speed-up 24p content to play at 25p (effectively 1:2 pulldown at 50Hz).

This is my perfered method for watching HD-DVD and US TV rips on my setup. I do not need Reclock for PAL sourced material, but use it anyway, as it gives more accurate PC clock timings.

Clearly not an ideal solution as the pitch has to be altered to avoid chipmunk type voices (roughy 8% faster.....25/24), and not applicable to consumer equipment. But a better compromise for me. If my TV displayed 24p or 48p natively (like some CRT projectors), then that would be the way to go.

I believe you meant 2:2;)

But yes, HTPC is simply the best imo. The possibilities are endless
 
That's a really interesting post.

I still haven't grasped the concept between hard and soft motion. And as you have stated, hard motion would make the game hard to play... I think I would need to see the two side by side to get a clearer picture in my head.

What you mentioned about pixel response time and dark scenes is really interesting!! Let me explain: Many people and myself including, have mentioned they see really prominent smearing when playing either Xbox or PS3 on the Samsung series 6 LCD tv. This smearing only happens with dark areas, but it's absolutely shocking when it happens. I don't understand how it can be response related, as the TV has a stated response time of 6ms, where with this dark smearing, you can see the pixel trail / remains for nearly 1000ms! How is this possible?

This only a theory, so...

1. Not all LCD panels are prefect and overdrive sometimes gets incorrectly configured that causes overshoot, which results in slightly elevated pixel response time (highly noticeable in gray/dark tones)

2. Pixel response times are not fixed and can be affected by numerous factors including temp. Also, it would seem pixels take long times to switch between darker shades of color.

3. When dark contents are displayed, very little light is emitted from the backlight. This may allow us to see motion trailing due to the (near) absence of motion blur

Anyway, run the Pixel Persistence Test (click here to download) and select flag and chase test. See which tones produce the longest streaks
 
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This only a theory, so...

1. Not all LCD panels are prefect and overdrive sometimes gets incorrectly configured that causes overshoot, which results in slightly elevated pixel response time (highly noticeable in gray/dark tones)

2. Pixel response times are not fixed and can be affected by numerous factors including temp. Also, it would seem pixels take long times to switch between darker shades of color.

3. When dark contents are displayed, very little light is emitted from the backlight. This may allow us to see motion trailing due to the (near) absence of motion blur

Anyway, run the Pixel Persistence Test (click here to download) and select flag and chase test. See which tones produce the longest streaks

Thanks, I shall have a go when I get to use my Samsung TV later this evening.
 
Excellent thread.

I've been bemoaning this 24p problem on the thread for the new Philips 42PFL9803H LED Backlight panel:

http://www.avforums.com/forums/lcd-...l9803-led-backlight-2-000-000-1-contrast.html

I've owned the TV for almost 2 months and along with several other owners, i've been disturbed by this problem when playing 1080p Blu-ray.

I see there's confusion over the definition of the problem, between 'Low-motion' and 'Judder'. The effect we're seeing on this set is what i'd call a stutter on slow camera moves (tracks & pans); it looks as though i'm only seeing 12fps instead of 24. Is this 'low-motion', or 'judder'?

Obviously with Philips' HD Natural Motion' (HDNM) switched on, the 'stutter' is gone - movement is fluid. But as it's been said, this artificial video look is undesirable (it also gives movement an erratic speeded-up look). BTW, the HDNM has 3 settings: OFF, Minimum & Maximum (there seems to be very little difference between Min & Max ).

Oddly the Philips manual for this TV says it displays 1080p at 24Hz, 25Hz, 30Hz, 50Hz, 60Hz. You can see the full technical data on p.50 here:

http://www.p4c.philips.com/files/4/42pfl9803h_10/42pfl9803h_10_dfu_eng.pdf

So am i write in thinking that if the TV can process 1080p at 24Hz there should be smooth motion (with HDNM switched off)?
If so, then why are we seeing this stutter?

(FYI, when i switch HDNM on/off the screen goes black for less than a second, though not when switching from MIN to MAX HDNM.)

To be honest this TV cost us a fortune, so we'd be pretty gutted if it wasn't doing what it was supposed to.

Hope you can help. Cheers.

BTW, I use a Sony 350 BD player through a Sony 820 receiver/amp as well as a PS3. Stutter is the same whatever configuration i use, with or without the amp.
 
Obviously with Philips' HD Natural Motion' (HDNM) switched on, the 'stutter' is gone - movement is fluid. But as it's been said, this artificial video look is undesirable (it also gives movement an erratic speeded-up look). BTW, the HDNM has 3 settings: OFF, Minimum & Maximum (there seems to be very little difference between Min & Max ).

.

There is a difference on how it handles a panning & moving camera.
Ie. moving on rails , and turning following a moving object.
Whilst both Min & Max exhibit the same (video) type motion , Min does tend to reduce the amount of blurring in high movement scenes.

So am i write in thinking that if the TV can process 1080p at 24Hz there should be smooth motion (with HDNM switched off)?
If so, then why are we seeing this stutter?

This is what the consumer expects , but if you watch on a display that is not 24hz compatible , trust me the Stutter turns to JUDDER which is a big problem.
 
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You are right, it's low-motion. I and many others see the same thing with pan scenes when watching blu-rays. It looks like it's running at far less than 24 frames per second doesn't it?! Don't get this mixed up with judder though, as judder, as which has been well discused in this thread, will give the appearance of inconsitant motion, like it's speading up and slowing down...
 
Thanks, I shall have a go when I get to use my Samsung TV later this evening.

I had a very quick play with this last night. I did the chase test, and the results were very good from what I could see. The screen exhibited very little blurring, and the different colours made no difference. This is absolutely nothing compared to what I've been noticing when playing certain games. How odd... Maybe it's just a "feature" of the Samsung TV.
 
Obviously with Philips' HD Natural Motion' (HDNM) switched on, the 'stutter' is gone - movement is fluid. But as it's been said, this artificial video look is undesirable (it also gives movement an erratic speeded-up look). BTW, the HDNM has 3 settings: OFF, Minimum & Maximum (there seems to be very little difference between Min & Max ).

Interesting. Frame interpolation technology must vary a lot between manufacturers. The lower of the 2 Motionflow settings (Standard) on my Sony also solves the low motion problem but has only a marginal effect on the filmic look. There is however a very noticeable difference between this and the High setting which does give an unacceptable very "videoy" look.
 
I had a very quick play with this last night. I did the chase test, and the results were very good from what I could see. The screen exhibited very little blurring, and the different colours made no difference. This is absolutely nothing compared to what I've been noticing when playing certain games. How odd... Maybe it's just a "feature" of the Samsung TV.

Have you tested gray flag or box against black or darker shade of gray

You may also want to test the darker tones as well.
 
As for Duncanc and and others



1. The TVs you guys have mentioned simply cannot process 24p properly, in which case, frame interpolation many be of some use.

2. The TV has not been configured correctly. There must be a setting that's causing the issue.



PS: This is unrelated to 24p, but few days ago, someone ask me for help regarding stutter and frame drops. As it turns out, a feature (Cinemotion) was enabled which was causing the issue.

So check each settings to make sure that it isn't caused by incorrect configuration.
 
24p simply shows the movie as it was shot. If that original movie had lack of smoothness in pans, then so will the bluray.

I much prefer that to the artificial solutions which add frames to smooth things out. They often end up looking like they were shot on video - too smooth.


I'd be happy for movies to use a higher frame rate, and to watch that on my TV. But until then I want it authentic. Just like I want my b&w movies not to be colourised.
 
Thanks for your replies. I've got answers for a few:

24p simply shows the movie as it was shot. If that original movie had lack of smoothness in pans, then so will the bluray.

I've seen Bladerunner at the cinema and the pans have no stutter - very smooth - same goes for Black Hawk Down. On my 9803 there's stutter (low-motion).

1. The TVs you guys have mentioned simply cannot process 24p properly, in which case, frame interpolation many be of some use.

I'd really appreciate it if you could look at p.50 of the specs (i gave a link below) and tell if this TV is supposed to do this. It says '1080p 24Hz processing...'
2. The TV has not been configured correctly. There must be a setting that's causing the issue.

I've tried turning all settings to OFF, but still the same stutter. BTW, the TV has a 'MOVIE' setting, which turns off HDNM, but it still stutters (it also locks the Tint to 'warm', rather than 'natural' which is annoying!)

PS: This is unrelated to 24p, but few days ago, someone ask me for help regarding stutter and frame drops. As it turns out, a feature (Cinemotion) was enabled which was causing the issue.

Maybe a dumb question, but how is this stutter unrelated to 24p, when it's only when watching 24p movies that this stutter happens?

Interesting. Frame interpolation technology must vary a lot between manufacturers. The lower of the 2 Motionflow settings (Standard) on my Sony also solves the low motion problem but has only a marginal effect on the filmic look. There is however a very noticeable difference between this and the High setting which does give an unacceptable very "videoy" look.

Very slight difference on the 9803 - the video look is badly apparent on the MIN setting.

You are right, it's low-motion. I and many others see the same thing with pan scenes when watching blu-rays. It looks like it's running at far less than 24 frames per second doesn't it?! Don't get this mixed up with judder though, as judder, as which has been well discused in this thread, will give the appearance of inconsitant motion, like it's speading up and slowing down...

Thanks, i'll refer to it as 'low-motion' from now on. However, the inconsistent motion you describe as 'judder' is exactly what i get if i switch on HDNM (the equivalent to 'Motionflow').

There is a difference on how it handles a panning & moving camera.
Ie. moving on rails , and turning following a moving object.
Whilst both Min & Max exhibit the same (video) type motion , Min does tend to reduce the amount of blurring in high movement scenes.

It does reduce bluring, but it makes Black Hawk Down look like an episode of Neighbours:suicide:

This is what the consumer expects , but if you watch on a display that is not 24hz compatible , trust me the Stutter turns to JUDDER which is a big problem.

As i said, it'd be great for someone with better knowledge of this (anyone but me) to look at the specs on this telly - it says '1080p 24Hz processing'. If the TV's not actually compatible with 24p, then surely this is false advertising!

Thanks everyone for taking the time to reply:)
 
Maybe a dumb question, but how is this stutter unrelated to 24p, when it's only when watching 24p movies that this stutter happens?

Because that was 24p source @ 60Hz using the X360. It was also a US BRAVIA model

I was just using that as an example
 
Because that was 24p source @ 60Hz using the X360. It was also a US BRAVIA model

I was just using that as an example

Doh! Sorry, i misread your reply - i thought you meant that my post was unrelated, but you meant your comment:suicide:
 
Thanks for your replies. I've got answers for a few:


Thanks, i'll refer to it as 'low-motion' from now on. However, the inconsistent motion you describe as 'judder' is exactly what i get if i switch on HDNM (the equivalent to 'Motionflow').


That's probably something to do with all the processing that's going on with the MotionFlow. If it's predicting frames to add in between frames, who knows what the result will look like!?
 
That's probably something to do with all the processing that's going on with the MotionFlow. If it's predicting frames to add in between frames, who knows what the result will look like!?

Rubbish! That's what it looks like ;)
 
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I've just watched a segment of Apocalypto on BRAVO and it would appear fast moving segments were filmed with lower shutter speed or motion blur was artificially added to make the motion appear smoother.

It's effective, but also appears unnatural/artificial


PS: One doesn't have to use high-motion to achieve fluid motion. One can simply use 29.97fps coupled with motion blur to achieve fluidic motion. If you'd like a sample, try and get hold of Final Fantasy XIII and vs XIII DKS3713 trailer.


I think next gen consoles may feature an advanced real-time motion blur technique, which I would love to see. I'm sure most of you're aware, the current implementation doesn't always work. At times, I prefer the motion to be raw without any filters.
 
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I've just watched a 3 minute segment of Lara Croft 2 on my computer and the motion was tad smoother than PAL DVD @ 25p.

The video was an HD sample encoded at 24p and the monitor's refresh rate was set to 72Hz (3:3 pull-down).

So yes, something else must be causing the problem for you guys. I may go down to my local Comet to test few sets and see what could be causing the effect, but I can't promise anything.


PS: I've also tested few other 24p contents and they all appear to be equal/slightly better than 25p.
 
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That is due to the TV failing to process 24p properly.

I'm well aware of that

btw, 2:3 doesn't drop any frames. It simplt displays one longer than the other.

I'm well aware of that too, but thanks for the clarification. My terminology isn't exactly accurate.

I think that called film jitter (vibration). But I'm not 100% sure

Jitter I've not seen except on anologue channels when the reception has been poor. At least that would be my definition.


No it doesn't

Are you telling me that LCD's do not contain fluorescent lighting or that it does not flicker? I beg to differ on both CCFL means Cold Cathode Fluorescent Lamp which I'm sure you are aware of. And lighting can and does flicker, especially fluorescent lighting. It tends to happen if it's out of phase with other factors - like electricity supply at a certain hertz or the opening and closing of pixels on a panel. Much like the blades of a helicopter look out of phase at certain speeds/angles and to certain people. So it's a rough analogy, but it still applies.



oh where to begin

VERY RUDE! You may know more than a lot of people on this forum, but acting like some kind of authority on the subject does not give you the right to make people look stupid or small. Maybe helping some of us to understand better by putting explanations in laymen terms or useful analogies would be more useful than short shrift, "yes, no, I'm smarter than you" remarks.

Do you buy any chance have Xbox live and mic?

No I don't have Xbox
 
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I'm well aware of that





VERY RUDE! You may know more than a lot of people on this forum, but acting like some kind of authority on the subject does not give you the right to make people look stupid or small. Maybe helping some of us to understand better by putting explanations in laymen terms or useful analogies would be more useful than short shrift, "yes, no, I'm smarter than you" remarks.



No I don't have Xbox

M8 he's not being rude - just saying it's a huge topic and is offering to help and explain to you further over xbox live!
 
Are you telling me that LCD's do not contain fluorescent lighting or that it does not flicker? I beg to differ on both CCFL means Cold Cathode Fluorescent Lamp which I'm sure you are aware of. And lighting can and does flicker, especially fluorescent lighting. It tends to happen if it's out of phase with other factors - like electricity supply at a certain hertz or the opening and closing of pixels on a panel. Much like the blades of a helicopter look out of phase at certain speeds/angles and to certain people. So it's a rough analogy, but it still applies.
It does flicker, but most of the time it's beyond out visual capacity to detect it.

If I remember correctly, you said it flickers at 50Hz, which is absolutely wrong cos at that level, everyone can detect image flicker/trailing.





VERY RUDE! You may know more than a lot of people on this forum, but acting like some kind of authority on the subject does not give you the right to make people look stupid or small. Maybe helping some of us to understand better by putting explanations in laymen terms or useful analogies would be more useful than short shrift, "yes, no, I'm smarter than you" remarks.


No I don't have Xbox

I wasnt being rude lol

I don't have the time to answer each one in detail, especially now (uni). That's why I offered to help via live.
 
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When a TV manual says it 'processes 1080p at 24Hz' and lists 24Hz among the frequencies for 1080p in its format list, does that mean that the panel will refresh at 24Hz, or that a 50/60Hz panel will process 24Hz using a pulldown?
 

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