BLURAY MOTION JUDDER

[aliEnRIK]

http://www.projectorcentral.com/judder_24p.htm

Quite a few of us are encountering 'judder' whilst watching blurays at certain points on a disc. Whilst you 'may' have set up wrong, the discs themselves are at fault (due to being 'only' 24fps)

"The industry standard 24 fps film rate is an albatross that we've been
stuck with ever since. As it turns out, it is way too slow to resolve
camera panning motion cleanly. So when a movie camera pans at an
unfortunate speed, you get motion judder. Sometimes you get it in
spades. The sad fact is, your high resolution 1080p/24 system is simply
showing you the picture as encoded on the Blu-ray disc in its authentic
naked form. We just never saw it in our homes quite as naked before the
advent of Blu-ray and HD DVD."

"As it turns out, the opposite is often the case. The motion judder in
native 24p can be atrocious. You can test it yourself if you have the
equipment to do it. We'll assume that if you have a Blu-ray player, you
are more likely to have a copy of Casino Royale than Casablanca.
If you do, find a messy panning scene in Casino Royale. There are lots
of them, but there's a real beauty in the 9th chapter, starting at 1
hour, 11 minutes and 13 seconds. The dealer is dealing, and the camera
pans slowly around the table."

"In 24p playback, this scene is a pure, unmitigated disaster. The people
seated at the table come apart at the seams, the tuxes flash and
strobe, the Casino Royale logo on the card table blinks like a neon
sign. Once you've replayed this travesty a few times, switch your
Blu-ray player to 60p output and run it again. Yes, it is still a mess.
But look at it closely ... the juddering effect is actually reduced.
That is because the 3:2 pulldown is blurring and masking some of the
latent motion judder in the film"

So whats happening is your bluray and tv are showing you exactly whats on the disc 'as is'. So the best you can hope for is a decent 'interpolation' on your tv (motion flow on sonys etc)

 

[Frank Harvey]

The only problem with relying on 'motion flow' and all other similar trickeries is that many of them look naff. Some people love it because it's smooth, but when I see 200 and 600Hz TV's I shudder (or is that judder?

) when I watch them. I personally couldn't live with any of the frame interpolation processes I've seen - TV's or projectors. Firstly because it looks unnatural. Secondly, it make everything look like it's moving faster than it actually is - try it - watch a film on a 600Hz Panny. Sorry, not for me! But then, I never really got on with 100Hz TV's either.

Oh, and when a film is played back at 24fps, it's running at the correct speed - Region 2 DVD's used to get on my nerves when a song I knew started in a film (Tears For Fears for example in Donnie Darko) and it was way too fast and higher pitched. Again, it's just wrong.

 

[ear]

it is not easy...bt that is true..one gets used to judder..but some movies have just to much of it

 

[Anonymous]

So does that mean that its blu-ray thats at fault or is it something else. Should the film be put on the disks differently or is the format not up to it and again we need a newer better system than blu-ray?

 

[aliEnRIK]

FrankHarveyHiFi:
The only problem with relying on 'motion flow' and all other similar trickeries is that many of them look naff. Some people love it because it's smooth, but when I see 200 and 600Hz TV's I shudder (or is that judder?

) when I watch them. I personally couldn't live with any of the frame interpolation processes I've seen - TV's or projectors. Firstly because it looks unnatural. Secondly, it make everything look like it's moving faster than it actually is - try it - watch a film on a 600Hz Panny. Sorry, not for me! But then, I never really got on with 100Hz TV's either.

Oh, and when a film is played back at 24fps, it's running at the correct speed - Region 2 DVD's used to get on my nerves when a song I knew started in a film (Tears For Fears for example in Donnie Darko) and it was way too fast and higher pitched. Again, it's just wrong.

I completely agree mate. All the 'motion' modes look awful to me. I must admit that sonys 'motion flow' is probably the best ive seen. But every so often the picture looks totally unreal (Especially on fast moving scenes)

So theres really not an awful lot anyone can do for a 'proper' fix (Or until the manufacturers actually release a motion process that DOES do what its supposed to)

What I dont get is that theres nothng to stop them creating a 'blurred' image to compensate anyways. Its just lazy encoding to me

 

[aliEnRIK]

eremis6:So does that mean that its blu-ray thats at fault or is it something else. Should the film be put on the disks differently or is the format not up to it and again we need a newer better system than blu-ray?

Its the encoding at fault. Theres nothing to stop them creating a slight 'blur' effect at the judder points.

Film is 99% of the time actually filmed in 24fps which is why theyve made blurays the same standard ~ no conversions necessary (Save the judder problem)

Until the whole industry changes its standard then this is all we have for now

 

[Anonymous]

Projector Central has taken the sales pitch of frame interpolation as fact. Frame interpolation is not needed due to the short comings of 24fps Blu-rays being made obvious by wonderfully revealing displays. But because of the failings of the display technology, it being incapable of displaying 24fps as it was intended to be shown.

Blu-ray 24fps does not have inherent motion judder. It does have inherent strobbing which is worse the brighter you display the image and the reason why 24fps are displayed as 48fps or 72fps in cinemas. Some people describe this strobbing as judder.

The only cause of motion judder inherent in the film is if the film makers make glarring errors in how the film pans, or moving objects are filmed exposing the limitations in 24fps filming that are well known and well documented and taught to every film maker and in every book about how to film motion pictures. These mistakes are not made by film makers as they are well known and glarringly obvious. They are limitations on what can be filmed and how it can be filmed, not causes of motion judder on the end product.

Tv programs have been traditionally filmed at 50Hz PAL or 60Hz NTSC for display on CRTs matching those refresh rates. Films are shot at 24fps for display at 48fps in a cinema. What causes motion judder is uneven pull down, displaying 24fps as 60fps, which is something American NTSC has done for years but is new to the UK with Blu-ray. PAL 50Hz doubled the 24fps and slightly sped it up, no uneven motion judder. NTSC 60Hz used 3:2 uneven pull down on 24fps causing motion judder. But this will not be present with a display capable of doing even pull down with 24fps which is most modern displays.

Nothing is shot to match the display technology used today LCD, Plasma, DLP projectors. The problem of motion judder arises because the display technology does not match the film recording technology.

With 24fps the image is suppose to be flashed on to the screen so your brain fills in the gaps in time making the motion smooth. Frames are only snap shots of time they are not suppose to be held in place. The brain fills in these gaps because when tracking objects if one passes behind a tree and reappears the other side you do not see it as a new object but as the same object moving, the eyes photo-receptors are behind the blood vessels on the eye, there are lots of blind spots on the eye with the eye-brain filling in the gaps to give us seemless vision. Also the eye only focuses on a small area at a time so we see an image that is collected over time and displayed all together as a cohesive whole. Involuntary saccadic eye movement naturally jumps to any bright moving object, perephhiral vision likewise is more movement sensitive than detail sensitive. Displays occupying a large portion of your field of view like projector screens are less prone to give the viewer motion judder because they work naturally with the eyes motion tracking, rather than having everything of intrest in the central more detail sensitive are of the eyes field of view.

Of the modern display technologies LCD is the worst for motion blurring and juddering, it inherently holds the image on the screen untill the next frame comes along, so it jumps instantly frame to frame instead of having the needed moment of blackness between frames to force your brain to fill in the gaps. Depending on how fast the object on screen is moving and if it is an object you are intrested in or involuntarly tracking with saccadic eye movement or peripheral vision, it will appear to blur or jump as the eye/brain attempts to do smooth pursit reflex to track the object. That is why frame interpolation is used to make these jumps of moving objects or pans in a image between frames less big. Even if this makes movement seem fluid it usually gives the eye too much time to collect data from the individual frames they lack natural motion blur caused by the eye lacking the time to collect data as the object moves too fast. It is as if someone has upgraded your eyes without telling your brain, the amount of detail they can collect is higher than it should be given the speed of the moving object, giving a odd hyper real look that some love and others hate. Because resolving detail - what is in focus, determines the depth of field of view, this can cause the image to appear to have more depth, some viewers find this effect pleasing especially with cgi animation. Lcd can use black frame insertion instead of frame interpolation but it impacts maximum brightness and contrast.

 

[aliEnRIK]

"Tv programs have been traditionally filmed at 50Hz PAL or 60Hz NTSC for
display on CRTs matching those refresh rates. Films are shot at 24fps
for display at 48fps in a cinema. What causes motion judder is uneven
pull down, displaying 24fps as 60fps, which is something American NTSC
has done for years but is new to the UK with Blu-ray. PAL 50Hz doubled
the 24fps and slightly sped it up, no uneven motion judder. NTSC 60Hz
used 3:2 uneven pull down on 24fps causing motion judder. But this will
not be present with a display capable of doing even pull down with
24fps which is most modern displays."

Im sorry but even my dads 500A pioneer which is STILL considered the best tv in the world to date shows judder in 24fps

Ive also slowed blurays down to a frame by frame rate which pretty much proves its how the discs are encoded, as I viewed them frame by frame and not as intended

 

[Anonymous]

Films are shot at 24fps designed to be displayed in a cinema. Any motion judder is the result of the display or incompentent film making which is not likely. Have you seen this judder every time you have gone to a traditional film (not digital) cinema, every time you have ever watched a film on any 50Hz PAL TV?

The idea that motion judder is inherent to 24fps films or that you need a massively high display refresh rate to give smooth detailed motion is wrong. If it was correct we would be used to unsmooth motion having seen it in every film we had ever watched. Instead people are starting to notice it and complain about it because they see it on these modern displays.

The human eye perceives the typical cinema film motion as being fluid at about 18fps, because of its blurring. Films are shown at higher than 18fps, usually 48fps or 72fps in cinemas due to sensitivity to black flicker. Show each frame 3 times and make the screen black 3 times per frame. This makes the black moments shorter and more frequent: "Triple the refresh rate". So you see about 72fps in the cinema, where 3 consecutive frames are the same. An example how "Brightness eats darkness". Bright image > after image on eye > no flicker.

All modern displays display each frame longer than they would be displayed at the cinema. Even your dads plasma tv. Manually advancing each frame is even worse, of course there is visible motion jumping - juddering, images are snap shots in time. You need the black gaps inbetween the frames to make your eye-brain smooth the motion.

Blue-rays on modern displays have the problem that blurring simulates fluidity, sharpness simulates stuttering, foveal slip. Making the image more blurry to combat the effect of displaying each frame too long due to the display technology defeats the point of high definition with moving images.

 

[aliEnRIK]

Ive just upgraded my 42" pioneer plasma to a sony 46"

The 'judder' was still there on the pioneer so everything youve just described is out the window for me

I'll reiterate, I have seen blurays FRAME BY FRAME. The reason it shows judder is because its ON THE DISC.

As for all other framerates, we then get into 'deinterlacing' and 'pulldowns' (Dependant on what the original framerate was to begin with). Have I seen judder on anything but 24fps? Yes I have, and thats the 'pulldown' problem.
"But this will not be present with a display capable of doing even pull down with 24fps which is most modern displays." (By the way, incorrect terminology when you class 24fps as 'pull down')

 

[Anonymous]

Taking a look at Casino Royale. There are scenes that are shot badly for motion. Lots of scenes especially action scenes have been shot with a hand cam, any visible judder is due to hand - camera movement.

Some camera pans are too fast with scenes containing strong verticals with too much horizontal displacement, the brain does not pickup coherence in these so they are not seen as moving but jumping. The scene needs to be reshot with slower pan or the strong verticals removes for motion to look smooth.

These handcam and too fast pans would look the same even in a film cinema or on a pal dvd copy on a 50Hz CRT.

But if you can see judder in the following it is your display. Chapter 17 starts with smooth fast camera pans. They exhibit no judder. 1.35 the long camera pan across the desert. No judder. End credits. No judder.

 

[aliEnRIK]

Knightout ~ I think you just seem to be completely ignoring everything ive said. I was watching one of the 'bourne' movies just yesterday and slowed it to a frame by frame account. The bluray was encoded that way. end of.................

Not ALL scenes have judder. I never once said that. But those that HAVE (That ive thus far checked) have ALL been encoded that way. Thats NOT my display, thats the bluray disc. Please dont ask me to repeat that again

(Casino royale ~ 'shakey cam' isnt judder. I never said it was)

 

[ear]

aliEnRIK shhh...dont fight...or he will puncture the tyres on your spaceship

 

[Anonymous]

I do not get how this is a Blu-ray > High definition specific problem rather than a how the motion picture was filmed problem and so present on the film regardless of Blu-ray or Dvd, High definition or Standard defintion.

You seem to be saying it is due to the way it was encoded on to the Blu-ray. Since pal dvd just doubles 24fps then speeds it up a bit any uneven motion juddder present in the original 24fps film should also be present on the pal dvd. Do you also see the same judder watching the film or on the disc frame by frame, with a pal dvd of the same film. If you do not then it must be caused by how the Blu-ray is encoded. If you do then it is how it was filmed.

Filming at 24fps imposes limitations on how movies are shot, if they are ignored then you do get noticeable motion artifacts. But switching the blu-ray player over to 60Hz as stated in the Projector Central article you orignally refered to should not decrease the motion judder as they state, if anything it should make it worse by introducing uneven pull down judder.

The only way this becomes a Blu-ray > High definition display specific problem is if there is a fundemental flaw in the way Blu-rays are encoded adding judder, or in the way High definition displays display 24fps not enough screen black out time to make the eye-brain smooth the motion by filling in the gaps in time. High definition is sharper and sharpness induces the perception of stuttering movement, while blurr induces smooth movement, so it could be part of the problem when compared to dvd. Likewise brightness improves the perception of contrast and sharpness so it could be part of the problem when compared to relatively dimmer film cinemas.

 

[aliEnRIK]

Im bored now...........

 

[Anonymous]

If anyone wants to see if their blu-ray player or display causes motion issues, I would recommend using snell and wilcox zone plate test patterns. They consist of a grey square in side which a circle moves bouncing off the sides of the square, the circle contains smaller circles, alternating between black and white circles. These test patterns are on the Digital Video Essentials Blu-ray disc and could probably be found online. Any motion stuttering, juddering, blurring, jagged lines, etc... you see on these test patterns are being caused by the blu-ray player or display, the motion should be smooth and the circles clean.

As I have said above I agree filming at 24fps can cause motion issues, particularly with too fast pans across strong verical lines which the eyes-brain fails to see as a cohesive smooth movement. This is being caused by the film maker not taking into account the limitations of filming at 24fps. It is not being caused by Blu-ray being 24fps or High definition displays, it will be present on the standard definition pal dvd and present when displayed on a standard definition 50Hz display. Frame interpolation may reduce this but it has its own issues.

 

[The_Lhc]

Whilst these circular arguments are endlessly fascinating it would be nice if someone could tell me what I need to do to stop the juddering on my (1080/24p compatible) KRP-500a with my Sony BDP-S760.

The Sony IS passing 24p to the screen and I've got judder, so what isn't set right?

 

[jase fox]

Hi Rik,

To be honest mate i havnt noticed any judder whilst watching Casino Royale, but ill be looking for it now the next time i watch it...

 

[PJPro]

the_lhc:
Whilst these circular arguments are endlessly fascinating it would be nice if someone could tell me what I need to do to stop the juddering on my (1080/24p compatible) KRP-500a with my Sony BDP-S760.

The Sony IS passing 24p to the screen and I've got judder, so what isn't set right?

If the judder is on the disk, then you are going to struggle unless you have interpolation software which can detect the judder and and remove it.

 

[Anonymous]

the_lhc:

Whilst these circular arguments are endlessly fascinating it would be nice if someone could tell me what I need to do to stop the juddering on my (1080/24p compatible) KRP-500a with my Sony BDP-S760.

The Sony IS passing 24p to the screen and I've got judder, so what isn't set right?

Not familiar with the KRP-500a but I have read in standard mode it is 60Hz, but it can be set to 72Hz, 75Hz and 100Hz.

If you have not already done so try setting the KRP-500a to pure cinema mode, you may also have to set it at 72Hz in a advance menu as some TVs also have a 60Hz pure cinema mode. You want 72Hz for a even multiple of 24fps.

To reduce judder with 50Hz input material like Sky HD rather than Blu-rays, you may need to switch to drive mode 2 100Hz or drive mode 1 75Hz , you do not want to use drive mode 3 60Hz. Most people seem to prefer drive mode 2. Drive modes should only effect how 50Hz input is displayed.

 

[The_Lhc]

knightout:the_lhc:

Whilst these circular arguments are endlessly fascinating it would be nice if someone could tell me what I need to do to stop the juddering on my (1080/24p compatible) KRP-500a with my Sony BDP-S760.

The Sony IS passing 24p to the screen and I've got judder, so what isn't set right?

To reduce judder with 50Hz input material like Sky HD rather than Blu-rays, you may need to switch to drive mode 2 100Hz or drive mode 1 75Hz , you do not want to use drive mode 3 60Hz. Most people seem to prefer drive mode 2. Drive modes should only effect how 50Hz input is displayed.

I use drive mode 2 for Sky because it kills all the shuddering when the camera pans left and right when watching football, the juddering I'm seeing is only with Blu-Ray, specifically 2001 as that has some shots of the Jupiter ship moving very slowly across the screen, where the effect is most noticable.

Not familiar with the KRP-500a but I have read in standard mode it is 60Hz, but it can be set to 72Hz, 75Hz and 100Hz.

If you have not already done so try setting the KRP-500a to pure
cinema mode,

hmmm, I'll check the options, I though I had it in Pure mode already, not sure if this is the same as "pure cinema mode" though, I don't recall seeing that particular phrase in the menus.

you may also have to set it at 72Hz in a advance menu as
some TVs also have a 60Hz pure cinema mode. You want 72Hz for a even
multiple of 24fps.

To be honest, I've not seen any reference to refresh rates at all, in any menu. I'll have a dig about...

 

[aliEnRIK]

jase fox:Hi Rik,

To be honest mate i havnt noticed any judder whilst watching Casino Royale, but ill be looking for it now the next time i watch it...

Ill be honest, I havnt looked for it either. But having watched a couple of 'bourne' movies I have noticed it in a couple of scenes (Its slight, but there all the same)

Im thinking of jumping to that scene in bond out of intrigue

I think some of this is down to what we perceive. I'll notice a whole lot more than a lot of other people. Its like some people are susceptible to 'phospher trails' on plasmas

 

[aliEnRIK]

knightout:

As I have said above I agree filming at 24fps can cause motion issues, particularly with too fast pans across strong verical lines which the eyes-brain fails to see as a cohesive smooth movement. This is being caused by the film maker not taking into account the limitations of filming at 24fps. It is not being caused by Blu-ray being 24fps or High definition displays, it will be present on the standard definition pal dvd and present when displayed on a standard definition 50Hz display. Frame interpolation may reduce this but it has its own issues.

Right, so on bluray we do agree then. DVD is different as the whole thing has been converted to work at that Hz anyways, which 'masks' the juddering (To a point). Of course the fact its converted then brings up its own 'judder' problems due to the 2:2 or 3:2 cadence drop down

 

[Deleted member 2457]

jase fox:Hi Rik, To be honest mate i havnt noticed any judder whilst watching Casino Royale, but ill be looking for it now the next time i watch it...

Jase Fox,

Nice system by the way, did you demo before you brought it? How did you know it was going to be a good match?

How does it all sound? I can't seem to find your B&W speakers on the B&W website are they now discountinued.

Thanks

 

[jase fox]

Hi Gel,

How does it all sound you say? Simply AWESOME !! And ive always preffered B&W speakers anyway & yes the speakers i have are now discontinued, WHSAV always highly rated them as they are great speakers. My centre speaker is the size of 2 breeze blocks its truly a fantastic piece of kit mind you at £450.00 it oughta be !! And the B&Ws work beautifully with pioneer amps, incredible sound, sometimes i cant believe the sound i get from my system especially with 2 subs connected, no matter who demos my set up there awestruck, i also use specialist powerkords etc which HAVE made a huge difference to the performance.