Topic: 24p

[jsnepo]

Hey guys. I'm not so informed about 24p so I have a few questions about it.

1. How does 24p work in displays that don't support Hz divisible by 24?
2. If my player supports 24p, will it output 24p in a non-24p display?
3. Do I have to have both display and player support 24p to get 24p?

[barrister]

I've been waiting for an answer from our techies, but since it doesn't seem like any replies will be forthcoming, I'll take a crack at it:

1. How does 24p work in displays that don't support Hz divisible by 24?

I haven't had an opportunity to test it, but I'm guessing you'll get a blank screen, since the input would be incompatible with the display's specs.

2. If my player supports 24p, will it output 24p in a non-24p display?
3. Do I have to have both display and player support 24p to get 24p?

24p should be supported by both player and monitor before a 24p video can be displayed properly.



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My Panny 50C10 plasma supports 1080/24p.  I recently got a Panny BD player, and I had high hopes that I would be able to play a movie in correct 24p cadence.

Well, guess what.  The judder on a 24p setting actually looks worse than on the default 60p setting.  What a bummer.

Apparently, 24p video is good in theory, but not so easy to implement in actual practice.  After some research, I stumbled on this article from Evan Powell, which explains 24 fps and "double shuttering" in cinema projectors:

The Big Judder Problem and the Overhyping of 24p
Evan Powell, November 11, 2008
http://www.projectorcentral.com/judder_24p.htm



This is the first time I've heard of double shuttering, so for the benefit of those who are similarly situated, here's a Wikipedia entry that explains double and triple shutters in movie projectors:

A commonly-held misconception is that film projection is simply a series of individual frames dragged very quickly past the projector's intense light source; this is not the case. If a roll of film were merely passed between the light source and the lens of the projector, all that would be visible on screen would be a continuous blurred series of images sliding from one edge to the other. It is the shutter that gives the illusion of one full frame being replaced exactly on top of another full frame. ...

... Modern shutters are designed with a flicker-rate of two times (48 Hz) or even sometimes three times (72 Hz) the frame rate of the film, so as to reduce the perception of screen flickering.

http://en.wikipedia.org/wiki/Movie_projector#Shutter




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According to U.S. forum posts, higher-end Panny plasmas are 48Hz-capable, but they still have bad judder and flicker; Pio plasmas are 72Hz-capable, have less flicker and judder, but the 72Hz setting sometimes causes artifacting.

So it seems that rendering a 24p source is not so simple after all.  BD was right in encoding discs at the native 24p rate.  However, the TV manufacturers must figure out what to do with the 24p source.

[Carlo777]

Hey guys. I'm not so informed about 24p so I have a few questions about it.

1. How does 24p work in displays that don't support Hz divisible by 24?
2. If my player supports 24p, will it output 24p in a non-24p display?
3. Do I have to have both display and player support 24p to get 24p?

Funny you asked that bec my wife just tested the PS3 with 1080p/24 on a non capable unit and it was filled with stuttering pictures!

I agree with barrister, even the G11 had noticable flickering problems with 1080p/24p activated, which brings me to my question...Is there any unit or model that is really capable of this much marketed feature?

I'll ask my wife to post her observations, she is the one really looking for the perfect 24p display...

[fitdynamite]

mga sir ano po ba tama setting sa popcorn hour 1080p/24 or 1080p/60? tnx advnce

[barrister]

...Is there any unit or model that is really capable of this much marketed feature?

I'll ask my wife to post her observations, she is the one really looking for the perfect 24p display...

I've been googling since yesterday, but I haven't come across any write-up about any TV that does 24p right.

LCDs are out of the question.  120 and 240 Hz are multiples of both 24 (BD) and 60 (progressive DVD), but 120 and 240Hz only give 24p sources an SOE (Soap Opera Effect) that is unwatchable for some people.

For Panny plasmas, the Gs do 24p, 48p and 60p, but unacceptable judder and flicker are still present on 24p and 48p settings.  Curiously, conversion to 60p (from a 24p source) is the most complicated, yet 60p still produces the best overall result.  Maybe it's because the manufacturers had much more time to get 60p right.

Pio plasmas can do 72p, but artifacting is the side-effect.  The regular 60p would be artifact-free, but you would also get the regular telecine judder.

U.S. forum posters say the V10 and Z1 Panny can do 96p.  However, they also say a slight flicker is still present at 96p, and that the regular 60p is still the best setting.  For example:


I have an interesting observation that doesn't quite make sense.

Just got the Ghostbusters Blu Ray ...

... I was playing around with my V10 48 vs 60 vs 92. @ 48 Hz flicker is obviously as all get out. @ 60 I can't see any flicker. @ 92 Hz I see very faint flicker noticeable in scenes with light colors. I had my roommate watch and he confirms my observations.

What's up with this?          

http://www.avsforum.com/avs-vb/showthread.php?t=1137650&page=64  (Post #1911)



And I thought 24p would have been such a simple spec to implement.

That's why I'm not too optimistic about 3D BD.  If they can't iron out the kinks on something as simple as 24p playback, how many more glitches should we expect from something as complex as 3D BD?