Buyers of 3D ready Plasma TV might be disappointed of the Avatar 3D BluRay

[Kerame Pxel Nume]

Some background info about my experience:

A few years ago I did a lot of stereoscopy (i.e. 3D) stuff. Mostly using CRT displays in conjunction with shutter glasses. Then LCDs became the standard technology and shutters got (temporarily) unusable.

Fast forward to Dec. 19th 2009, when I first saw Avatar 3D. WOW! This made me get my old stuff "from the attic", but instead of CRTs I now used some more sophisticated technology: Video Beamers + the polarizing 3D glasses from the cinema (RealD method), although you need a special screen. The other method would have been using shutter glasses (have them too, in cinemas this is XPan3D) or interference filter glasses (Dolby 3D), which work with any screen.

After a bit of fiddling around and experimenting with a variety of screen materials and the help of a friend who assisted my in making the screens we actually got it working  . It's not perfect yet, but it's a very good start.

Someone in this forum, posted a link to the 3D version of the Avatar trailer, irayo for that. So naturally I played it on our system. And it was a bit of an disappointment. The 3D effect was there, but not quite as good as in the cinema. What did happen? 

I realized, that aside the percieved angular size of the picture, which can be tuned by the viewers distance to the screen, there's one thing that can only be adjusted by physical size of the screen. And that is the stereo separation for points to be percieved at infinite distance. Ideally this distance on screen is the same as the average eye-to-eye distance of a human observer. And it is directly coupled to the so called "stereo width", which must be set prior to filming as there's no way to change that afterwards. The only thing adjustable in a small margin is the relative depth.

Well, to save material our test screens were no larger than maybe 1.50m x 0.7m, i.e. 65" diagonal. So we used one of our earlier, but unfortunately partially failed attempt for a polarization retaining screen, which was about double the size (3m x 1.6m). And even with the bad surface quality of the screen it was much better  . On the smaller screen the projected stereo width was just too short.

I suspect that JC adjusted the stereoscopy parameters for a good viewing experience on the big screen. However the very aspects of Avatar 3D which make it such a great 3D experience in the cinema, namely the carefully use of 3D, even reducing the effect in fast cut sequences, might be the cause for a big disappointment for those who get a fancy 3D ready 60" plasma. On those the 3D effect of Avatar might not look as good as in movies who totally overdid it.

Again: There is no way, you can adjust the "strength" of the 3D effect after a movie is shot. You can play around with the interception depth, but that's not the same and should be avoided, as a misaligned interception plane will cause nausea.

Which brings me to the following conclusion and suggestion. Avatar 3D looks great only on sufficiently large screens, 3m width upwards. So if you want to get yourself 3D ready for the Avatar 3D BluRay I'd go with a nice 3D ready HD video beamer - either with shutter glasses or the probably soon to arrive Dolby 3D consumer products. This gives you a way larger picture for your buck (and in this case size actually does matter).

[Hufwe ta'em]

I went to the Sony store a few week ago to try the new LX9000 LED 3D tv and the quality are very good, the glass are the RealD, only the discovery channel can provide the 3d support and the quality are very good.

[Kerame Pxel Nume]

I went to the Sony store a few week ago to try the new LX9000 LED 3D tv and the quality are very good, the glass are the RealD, only the discovery channel can provide the 3d support and the quality are very good.

I'm sure the quality was great. There's nothing bad about 3D-ready plasmas or LED TVs. Heck, if you've got the money for a huge one you'd like to watch Avatar on: Get it.

The thing is: It boils down to the parameters with which the 3D material was shot. Has it been intended to be shown on a big screen or only on a smaller TV screen. Depending on that the cinematographer will/should set apropriate stereo width and interception. And (unfortunately) Avatar has been shot for the big screen.

[Technowraith]

Why not try a projector and a blank wall? can projectors run in 3D?

[Will Txankamuse]

I'm pretty sure the '3d trailer' is home made and isn't a genuine trailer filmed using the 3d camera Cameron used.

Also, what is unique about JC's Camera that he used in Avatar is that the interocular distance can be changed dynamically - even while during a scene.  The two 'eyes' can swing towards each other as objects move towards the camera which means they truly simulate the human eye, unlike older 3d cameras which had fixed lenses.  This is why it's so important when watching Avatar to focus on the part of the screen that is in focus - he also uses quite a narrow depth of focus to enhance the 3d.

You can see more about the 3d camera JC used on the movie Avatar in this video here.

JC is a big fan of 3d, but he's also very vocal that a movie that is in 3d has to be designed from the start to be in 3d - you cannot 'retrofit' 3d into a non 3d film.  This is a reason why Clash of the Titans which is going to convert itself to 3d (somehow?) is going to be such a 3d disappointment in the movie theaters (and I hope it doesn't set the cause of 3d back).

Will

[Kerame Pxel Nume]

Why not try a projector and a blank wall? can projectors run in 3D?

It's actually two projectors with appropriate polarization filters. But you can't use just blank walls. On these light is scattered, which destroys the polarization. So you need either a method that's not based on polarization (shutter, or interference filter) or you get a polarization retaining screen.

You can buy the stuff that's used in cinemas, but it comes for ~100€/m^2. Maybe I'm going to get some of this. In the meantime I use the DIY stuff.

[Kerame Pxel Nume]

I'm pretty sure the '3d trailer' is home made and isn't a genuine trailer filmed using the 3d camera Cameron used.

Actually it's legit. The high compression of YouTube ruins it though. How do I know it: Well, as told I once did a huge amount of stereoscopy stuff, including image processing and developing tools for analyzing stereoscopic pictures. One of this tools calculates the "stereo histogram" of two given images. But since w/o knowledge of to read it, it's of no use, I show here the output of another of my tools, applied on a single frame pair of the trailer.



What can you see here? What's done is, that the images of left and right eye are shifted on the horizontal axis and their difference shown. Areas in which the images differ are bright the rest is dim. What you can see in the animation, is, that there is a dark region moving smoothly through the picture.This area corresponds to the percieved depth the corellates with the shift. Important is the smooth movement. Was is some fake stereoscopy effect, then there would be dim and bright areas popping in and out.

Also, what is unique about JC's Camera that he used in Avatar is that the interocular distance can be changed dynamically - even while during a scene.  The two 'eyes' can swing towards each other as objects move towards the camera which means they truly simulate the human eye, unlike older 3d cameras which had fixed lenses.  This is why it's so important when watching Avatar to focus on the part of the screen that is in focus - he also uses quite a narrow depth of focus to enhance the 3d.

You can see more about the 3d camera JC used on the movie Avatar in this video here.

I know all that. In fact I have built a DIY 3D cameras from two 720p HD camcorders that works just like the one of JC.

[EDIT] fixed a missing sentence.
[2nd EDIT] it's not legit as further analysis showed 

['Tsamsiyu]

I don't know much at all about the detail on this subject, but surely the Bluray 3D will be modified so that it plays well on any screen... or is that too simple?

And I don't mean to question your methods but the 3D trailer probably wasn't made to the standard of the movie... or is that too simple aswell?

[Kerame Pxel Nume]

I don't know much at all about the detail on this subject, but surely the Bluray 3D will be modified so that it plays well on any screen... or is that too simple?

And I don't mean to question your methods but the 3D trailer probably wasn't made to the standard of the movie... or is that too simple aswell?

Well. It is possible to reduce the "stereo width", i.e. the strength of the 3D effect afterwards, but it requires some video voodoo. With some dirty tricks it may be even possible to widen it, but this then based on extrapolation of data.

They could run another rendering batch for all the CGI scenes. But anything filmed with an actual camera is now fixed.

The trailer was probably created using material early of the CGI process - normally there are several iterations on that. But at this point the stereo width already has been set. There is however something that will compensate it to some degree: Visual detail. The YT video is totally overcompressed, thus lacking a lot of finer detail, which however is crucial for the brain to deduce the depth information.

But still, on a small the screen the 3D effect will probably not come out as cool as in the cinema.

[Will Txankamuse]

I found the trailer on youtube and watched it with the 'cross eye' method (yes I know this does nasty things with your eyes) and I was very impressed!  I've always found the cross eye method works really well for me in general, but with this video I was able to see all the 3d detail, even make out the the little 3d screens they use the movie.  Thanks for pointing me at the trailer ma Kerame Pxel Nume   Now I can't wait for the 3d bluray!  I'm probably going to go at least 60" or more when I buy a screen, since I've heard you need to go 'big' to really have 3D work at home, your posts seem to agree with that premise.

Will

[Eykyuan]

Kaltxi!

I wrote togeter what i know about 3d BluRay. (don't mind my bad english)
Be aware that Some stuff was already mentioned in foregoing posts.

How things work: 3d on DVD/BluRay discs

3d DVD:

The corresponding left/right images are stored in a interlaced format on the DVD.
The left/right images are divided into lines, for at least all interlaced formats in 525 lines like a NTSC or PAL-M signal.Now all
even numbered lines from the left image and all unevern numbered lines from the right image are merged into one image which now
contains the left/right eye information.
This will look like this: (with less than 525 lines)



This is done to reduce the amount of data to be stored on the DVD due to limited capacity. With this method a 2d and a 3d movie of
the same length require the same storage capacity.
But in the end when you are watching a 3d DVD the image has only half resolution of the corresponding 2d DVD.
This dramatically decreases picture qualtiy. There are also problems watching 3d DVDs on progressive scan devices like most Beamers
and TV-sets are.
I can't find any information about physical or file system specifications but I think the video is stored in some kind of Mpeg format
on the DVD.
Lots of 3d DVDs are also available in anaglyph versions. I don't like them.


3d BluRay:

3d BluRay doesn't use the interlace method because of a much higher available disc space. The video is stored in a MPEG4-AVC format,
the same one which is used for the digital cinema cartriges for cinema servers.
The first channel on the BD (BluRay disc) contains the left image of the 3d movie. The second channel contains the differential input of the left
and right image. This is done to reduce the data size of the movie and to make the 3d BD 2d compatible (you see only channel one if
you watch it in 2d).
There is no lack in image quality, both images (left and right eye) feature HD resolution.


I didn't find any official 3d avatar trailer released from Fox. All trailers I know are "homebrew" 3d versions of the 2d trailer in
interlaced or anaglyph versions.
The second eye image in these versions are created by the computher through shifting the original 2d image. There is no other way
converting traditional 2d in 3d video and the quality is very poor.

Why not try a projector and a blank wall? can projectors run in 3D?

Some can, some not. The main problems are too low frame rates of many particulary older projectors (flickering) and that most units
deinterlace the video signal.(only important if you project interlaced 3d videos) That will aslo improve with 3d BluRay.

I also did a lot of stereoscopic stuff but stopped all these projects due to 3d movies were only available on 3d DVD and interlaced
quality was so poor (we don't want to talk about anaglyph stereo ).
I didn't find any movies that provide single left/right images on the disc.
Lets see how it works with 3d BluRay but till now there are none available. Avatar will be the first movie published in that new format.

[...]The 3D effect was there, but not quite as good as in the cinema. What did happen?[...]

I didn't have any proplems with that till now using single left/right images, shutterglasses and a DLP beamer. For shure the 3d effect is
much mor bombastic on a 1000m² screen than on a 60" TV. I think this is based on that you are more "in" the movie if you don't see
the borders of the screen. In our town Avatar is shown on two different screen sizes. In the IMAX theatre on a over 1000m² large screen and on a 480m² screen. The 3d effect is much deeper in the IMAX theatre particulary if you sit in the fourth row (you can't see the screen borders).

Feel free to correct me any time.

Eykyuan

[HTML_Earth]

I found the trailer on youtube and watched it with the 'cross eye' method (yes I know this does nasty things with your eyes) and I was very impressed!  I've always found the cross eye method works really well for me in general, but with this video I was able to see all the 3d detail, even make out the the little 3d screens they use the movie.  Thanks for pointing me at the trailer ma Kerame Pxel Nume   Now I can't wait for the 3d bluray!  I'm probably going to go at least 60" or more when I buy a screen, since I've heard you need to go 'big' to really have 3D work at home, your posts seem to agree with that premise.

Will

Could you link me to it? I've only found one that was altered 2D and one that just made one eye see one frame ahead of the other.

[Kerame Pxel Nume]

3d BluRay:

3d BluRay doesn't use the interlace method because of a much higher available disc space. The video is stored in a MotionJPEG format,

No, BluRay3D does use another method. I think you confused it with 3D Digital Cinema, where each frame is stored as an independent JPEG2000 I-frame.

BluRay3D uses a quite interesting compression scheme; There's a main video track, which is for the left eye encoded using MPEG4-AVC which has the very same compression format as we already know from 2D BluRay. Additional to that there is an auxiliary track, that encodes all the differences of the right to the left eye. Where possible things like motion vector and prediction are shared by both tracks. This works quite well for most scenes as there's only very little difference. There are some pathological cases (like a close fence where a bar is on the left half of the picture for the right eye and vice versa), which will almost double the required space, but gladly those cases are also those, which cause serious headache for the viewer, so those will be unlikely to occour.

[EDIT]: On an additional note I'd like to point out, that the whole differential image encoding does not impair image quality. In fact using this kind of encoding scheme prevents different but otherwise invisible compression artifacts to emerge. If you just encode two independent videostreams, artifacts will appear at different positions, which is easily detected by the brain, while they would have stayed invisible, if they matched at both eyes.

Also if you omit the quantization phase in the compression, i.e. do a lossless compression, then differential encoding is bit exact, so no information lost for each eye.

[Kerame Pxel Nume]

Could you link me to it? I've only found one that was altered 2D and one that just made one eye see one frame ahead of the other.

Here you go:
Avatar S-3D trailer

[Will Txankamuse]

I'm still not convinced that the trailer linked is real 3d i.e. sourced from two separate videos (one left, one right).  I think it was simulated from a 2d feed by using the software (linked in the youtube video) that detects parallax and adds 'depth'.  I wouldn't get too disheartened by the YouTube...

The way to see this is to take a still frame (i.e. no camera movement!) that still has depth in it, and perform your analysis on that.  Since in a still frame the software that 3ddump uses to up convert to 2d to 3d cannot get the required parallax information to guess the depth parameters.  [edit] e.g. go to 1:01 when you see Grace turning towards Selfridge in his office - there is no camera movement there and so there is no depth at all (Grace does not pop out of the screen).  This is definitely simulated 3d [end edit]

I'm willing to be convinced otherwise, but I'm more in the camp that this YouTube is 'fake 3d'.  Have you tried playing some of the real 3d videos that are available on youtube on your 3d setup?

Will

[Kerame Pxel Nume]

[edit] e.g. go to 1:01 when you see Grace turning towards Selfridge in his office - there is no camera movement there and so there is no depth at all (Grace does not pop out of the screen).  This is definitely simulated 3d [end edit]

Hmm, well. We can see a short part of Jakes first videolog entry, there's absolutely no camera movement there, but is has some 3D effect. However, on close analysis it doesn't look right.

[Eykyuan]

3d BluRay:

3d BluRay doesn't use the interlace method because of a much higher available disc space. The video is stored in a MotionJPEG format,

No, BluRay3D does use another method. I think you confused it with 3D Digital Cinema, where each frame is stored as an independent JPEG2000 I-frame.

BluRay3D uses a quite interesting compression scheme; There's a main video track, which is for the left eye encoded using MPEG4-AVC which has the very same compression format as we already know from 2D BluRay. Additional to that there is an auxiliary track, that encodes all the differences of the right to the left eye. Where possible things like motion vector and prediction are shared by both tracks. This works quite well for most scenes as there's only very little difference. There are some pathological cases (like a close fence where a bar is on the left half of the picture for the right eye and vice versa), which will almost double the required space, but gladly those cases are also those, which cause serious headache for the viewer, so those will be unlikely to occour.

For shure you are right, they don't use MotionJPEG, I was a bit confused.
But I already wrote the same thing about these two channels/tracks.
For shure there are some cases that will almost double required storage space, but at last storage space is reduced to abot 75% of  what you need without that differential input method.

[bagget00]

As for the trailer being the cross eyed version, I remember those kids books with the hidden pictures. I was really good at thoe, but the problem is that almost all of the images are sunk and not popping out., I found that to be true with the trailer as well.

[Kerame Pxel Nume]

Okay, I did a further analysis on the trailer. It's a fake 3D one 

That my analysis tool didn't show up descreete layers, as I would have expected, i due to the fact, that some heuristics on the depth distribution in usual picture composition were applied. On a blogsite I found (another?) version of such a "upconverted" version, currently downloading, and comparing to what I got here.

I really don't understand, why Fox wasn't just releasing a true 3D version yet then. I mean, there are all those cool 3D displays becoming available now. *sigh*