You are not logged in. [Log In]


Forums » General Discussion » Technical Questions » 24p presentation on <120Hz displays

Topic Options
Rate This Topic
#237534 - 12/31/08 04:34 PM 24p presentation on <120Hz displays
bridgman Offline
axiomite

Registered: 08/25/04
Posts: 6024
Loc: Bowmanville, Ontario, Canada
Actually a heap of dumb questions. The background here is graphics drivers for HTPC and whether only 24p and 50/60 are needed, or whether we need to output some multiple of 24 (48, 72 etc..) depending on the quirks of the individual TV.

1. I had always been under the impression that movies on DVD had the 3:2 pulldown added during mastering and were stored on the disk as 60i. Now I am reading that "all movies on DVD are stored 24p and pulldown is applied when outputting to a 60i TV". Which is correct, and if 24p DVDs are common why don't BD players offer to drive a native 24p output from DVDs as well as BDs ?

2. I'm pretty sure that BD allows native 1080/24p storage on the disk and that most movie disks are recorded in that format, but could someone confirm ?

3. 24p output from player to TV is obviously useful with a 120Hz native display since the TV can either repeat or interpolate frames from 24 to 120 Hz without any funny processing. If you have a TV with a native 60p or 60i refresh then presumably 3:2 pulldown would be applied in the TV before display. OK so far ?

4. There seems to be hot debate about the existence of a "middle ground" solution, where :

- the TV (typically LCD or plasma) seems to be able to refresh at either 50 or 60 Hz in order to support multiple TV standards

- an additional "24p friendly" refresh frequency is supported, either 48 or 72 Hz

- when processing a 24p input, the frames are doubled/tripled or interpolated and displayed at 48/72 Hz, avoiding the funny effects you get during pans after 3:2 pulldown

I have read a bazillion forum threads and looked at a lot of highly ambiguous spec sheets (Sony spec sheets are right down there with Denon user manuals IMO ;)) but still have no clue if these "24p friendly" sets actually exist. So far it seems like most of them just apply 3:2 pulldown internally and display at 60p.

What's the story ?

EDIT - I finally found a couple of posts where owners complained about flicker when displaying 24p with 2:2 (48 Hz) so that seems credible ;\) Seems like maybe Panasonic offers some sets which double to 48Hz, Pioneer offers some which triple to 72 Hz, and a number of vendors claim "100 Hz" frame rate (presumably 4x or just under 96 Hz ?).

5. Finally, the one place where I see value in outputting at 48 or 72 Hz is in the case where you are going to a computer display which can natively refresh at that rate *and* you have a player app which will take care of doubling/tripling the frames and synchronizing them nicely with the display. Does anything like this exist today ?

Thanks ;\)


Edited by bridgman (12/31/08 04:40 PM)
_________________________
HT: M60ti/VP180/QS8, SVS PC+ 20-39, EP500
Music: M5HP, Sierra-1, M40ti
Idle: M2ti, M3v4, VP100
John

Top
#237669 - 01/01/09 08:12 AM Re: 24p presentation on <120Hz displays [Re: bridgman]
bridgman Offline
axiomite

Registered: 08/25/04
Posts: 6024
Loc: Bowmanville, Ontario, Canada
OK, after some digging I found answers for #4 anyways. Looks like there are a number of sets which display 24p at 48, 72 or 96 Hz although the trend is towards 120 Hz going forward.

http://forum.blu-ray.com/showthread.php?t=5155

I guess this adds question #6, which is "how does 120Hz display work with PAL & SECAM broadcasts at 50 Hz timing ?" ;\)
_________________________
HT: M60ti/VP180/QS8, SVS PC+ 20-39, EP500
Music: M5HP, Sierra-1, M40ti
Idle: M2ti, M3v4, VP100
John

Top
#237672 - 01/01/09 08:31 AM Re: 24p presentation on <120Hz displays [Re: bridgman]
MarkSJohnson Offline
shareholder in the making

Registered: 09/27/04
Posts: 11437
Loc: Central NH
I was going to offer a reply to your post, John, but I didn't think commenting on the cuteness of puppies would be terribly helpful~!
_________________________
::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::

Top
#237704 - 01/01/09 02:03 PM Re: 24p presentation on <120Hz displays [Re: MarkSJohnson]
thefwam Offline
local

Registered: 03/04/08
Posts: 229
Loc: Utah, USA
I would mention that before you spend extra money for the 120 Hz option on TV's I would check a set out running that mode. My father in law has one of the Pioneer Kuro sets, and while really amazing in most ways, it doesn't seem to do all that great with 24p, or so the reviews say. This may be the year the HDTV's really get it down, but while watching Dark Knight on blu ray the other night I found that I really didn't like the 24p when it did work that much, it just looks unnatural. And when it didn't work very well, it tended to mess with the image.
_________________________
Steve

Top

Moderator:  alan, Amie, Andrew, axiomadmin, Brent, Debbie, Ian, Jc 
Forum Stats

15,206 Registered Members
15 Forums
23,962 Topics
423,593 Posts

Most users ever online:
883 @ 03/04/17 05:06 PM

Top Posters
Ken.C 18044
pmbuko 16437
SirQuack 13565
CV 11675
MarkSJohnson 11437
0 registered ()
224 Guests and
6 Spiders online.
Key: Admin, Global Mod, Mod
Newsletter Signup