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Bluray Judder

C227

Standard Member
When I started looking for a plasma last year I went to alot of stores (specialist and mainstream) and straight away noticed a certain amount of judder on the Samsung and Panasonic plasma's when playing bluray. This included the 8 Series, G10 and V10.

Initially I thought it was poor setup or maybe just a substandard bluray player.

However, over the last few weeks I've noticed the exact same thing at home through a fairly decent bluray player (Pioner BDP-320).

It's only when the output is set to 60Hz but goes away completely with 24Hz.

I'm not even quite sure I can see a feasible difference in PQ between the two.

What's occuring?
 

paulr2006

Distinguished Member
The BD player should be set on 24Hz as this is the framerate the movie was shot at, I have never seen the slightest hint of judder on my V10 using this setting & frankly you would never see it on almost any decent TV providing it can accept [email protected]
 

C227

Standard Member
Thanks Paul,

stores must have had thei output set to 60Hz.

24Hz is totally smooth on my 850.
 

paulr2006

Distinguished Member

Noggin1980

Distinguished Member
It's only when the output is set to 60Hz but goes away completely with 24Hz.

This responce will almost certainly be slightly technically inaccurate, so forgive me but it should give you the jist of it.

Film content is filmed at 24 frames a second, so when you play it at 24hz all is well.

Playing at 60hz brings a problem, you can't make 24 go into 60, because of this frames are shown multiple times, some frames twice and some frames 3 times, this makes things judder especially on fast pans.
At 24hz it looks something like this frame :1,2,3,4,5,6,7,8,9...22,23,24
At 60hz it looks something like this 1,1,2,2,3,3,3,4,4,5,5,6,6,6 This is called 3:2 pulldown (I think)

Now you won't have noticed this untill blu-rays because 60hz is an american refresh rate and we used 50hz, 24 also doesn't go into 50 and this is solved by simply running the entire film 4% faster, this makes voices higher pitch and the film slightly shorter. Which of the two systems is less distracting is personal preferance and often based on what you grew up with.

So in summary American Dvds - judder. European Dvds - 4% speed up. Blu-rays - judder (unless shown at 24p)

Fortunatly if you have a tv/player that properly handles 24hz (or a multiple of it) 48hz, 96hz etc then this problem no longer exists with blu-rays.
 
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Toadus

Prominent Member
Any idea what happens to content not filmed at 24fps which then gets put onto Blu-ray? Planet Earth for example...

The reason I ask, and it's not down to judder, it's more the low motion aspect of it... Basically, watching Planet Earth on BD, I can see that it's been played back at 24fps, as the obvious low motion becomes apparent during pan shots. When I watched it on TV via a satellite broadcast, it was clearly being shown at 50fps. No low motion signs during pan shots - a bit like playing a video game which is being displayed at 60hz.

So the question is: Is it the actual BD which limits the frame rate transfer? Seems silly if it is...
 

YellowSphere

Prominent Member
So the question is: Is it the actual BD which limits the frame rate transfer? Seems silly if it is...
I think it's the international aspect of it, if it was shot natively at 25Hz then that's fine for UK TV (and should be fine for a UK released BD too), but Americans won't be able to watch it, they need it either changed to 60Hz or slowed down to 24Hz.
 

choddo2006

Distinguished Member
At 24hz it looks something like this frame :1,2,3,4,5,6,7,8,9...22,23,24
At 60hz it looks something like this 1,1,2,2,3,3,3,4,4,5,5,6,6,6 This is called 3:2 pulldown (I think)
Mostly right. the cadence is 1:1:1: 2:2: 3:3:3: 4:4 and so on. And anyone with a R1 DVD (which is most of us) might have noticed it before.
So in summary American Dvds - judder. European Dvds - 4% speed up. Blu-rays - judder (unless shown at 24p)
European content has the pitch adjusted to compensate, it doesn't sound higher. Superman does run 4% quicker though.
 

choddo2006

Distinguished Member
Any idea what happens to content not filmed at 24fps which then gets put onto Blu-ray? Planet Earth for example...

The reason I ask, and it's not down to judder, it's more the low motion aspect of it... Basically, watching Planet Earth on BD, I can see that it's been played back at 24fps, as the obvious low motion becomes apparent during pan shots. When I watched it on TV via a satellite broadcast, it was clearly being shown at 50fps. No low motion signs during pan shots - a bit like playing a video game which is being displayed at 60hz.

So the question is: Is it the actual BD which limits the frame rate transfer? Seems silly if it is...
Planet Earth is a bit of a mess. I suspect the whole thing got FRCed to 24 or 60Hz. I think it's impossible to eliminate judder on it even with a video processor. Not sure what else they could have done with so much mixed content though - you can't go changing framerate partway through (plus the American audience comment, maybe it's 50Hz to 60Hz causing the main problem)
 

mikelj

Prominent Member
Mostly right. the cadence is 1:1:1: 2:2: 3:3:3: 4:4 and so on. And anyone with a R1 DVD (which is most of us) might have noticed it before.

European content has the pitch adjusted to compensate, it doesn't sound higher. Superman does run 4% quicker though.

Pitch adjust isn't perfect though. When watching the R2 version of Serenity at a friend's house, I heard a few instances where it sounded like the actor's were on helium (however, I had watched my R1 version a couple of dozen times, so I was familiar with how it should sound). But if you'd only ever watched the R2 version, you'd never be any the wiser.

Still, not a problem these days with Blu-ray.
 

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