3D and 24p

[-Sandro-]

Hello,
I'm not very familiar with newest 3d technologies, but from what I've read I got that BD 3d used two 1080p images showed sequentially (not side by side like Directv TV and SKY UK) at 60hz per eye = 120hz TV.
Does it mean the 24p smoothness will be lost for movies? will a 3:2 pulldown be applied per eye?

[JamesN]

Originally Posted by -Sandro-

Hello,
I'm not very familiar with newest 3d technologies, but from what I've read I got that BD 3d used two 1080p images showed sequentially (not side by side like Directv TV and SKY UK) at 60hz per eye = 120hz TV.
Does it mean the 24p smoothness will be lost for movies? will a 3:2 pulldown be applied per eye?

24p (24fps) is the rate at which stereoscopic image pairs are delivered from a 3DBD player to a display. It is up to the individual display devices as to how those image pairs are ultimately displayed. For example, Panasonic's new plasma 3DTVs allow the user to select from three different refresh rates: 48hz, 60hz or 96hz (per eye).

Obviously any refresh rate that is not a multiple of 24 would require some form of temporal interpolation, such as 3:2 pulldown as you noted.

[-Sandro-]

so the "3d video" on the disc is encoded in 24p and not 30p?

[4K2K]

Originally Posted by -Sandro-

so the "3d video" on the disc is encoded in 24p and not 30p?

3D video on the disc on Blu-ray can only be encoded as 1080p24, 720p50 or 720p60. 3D films on Blu-ray will usually be encoded as 1080p24.

In 2D on Blu-ray, more formats are supported, eg. 1080/50i and 1080/60i (which could better support full res 30p).

[-Sandro-]

I didn't know 3d specifics cut 1080i50/60i out!
good to know, thanks

So it's everything up to the display how to show the content, do you know what producer is already making multiple-of-24 refresh rates already for showing stereoscopic content per eye except for the already mentioned Panasonic's Plasmas?

[Teazle]

More strictly, the 3D BD player sends to the display a doublesized frame, 1920x2205 IIRC, comprising two 1920x1080 images (one for each eye) plus some blanking, 24 times / sec. Officially it's not 1080p24 done twice but 1920x2205p24 done once.

The display then sorts this out depending on display refresh rate. Yes, for 120Hz (e.g. 2010 3D plasmas) there will be a telecine stutter type of effect as top and bottom halves of frames do not get shown for the same length of time (one eye gets an extra refresh for each frame).

Really 144Hz is needed for plasma just like theatrical DLP.

LCDs running at 240Hz or higher won't have the stutter, just blur or other oddities.

[dboyle]

Probably mentioned in some other thread but I heard that the only 1920x1080 video format supported for Blu-ray Disc 3D is 1080p23.976