Is a 2D bluray better quality than a 3D one? - AVS Forum

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NeilF's Avatar NeilF
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03-01-2012 | Posts: 405
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If you buy a 3D version of film on bluray, and watch it in 2D, is that the same quality as a dedicated 2D version, or worse?
gregzoll's Avatar gregzoll
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It would not be in 3D. It would actually just look normal, due to it would play the regular version of the movie (the player).
NeilF's Avatar NeilF
06:28 AM Liked: 10
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Quote:
Originally Posted by gregzoll View Post

It would not be in 3D. It would actually just look normal, due to it would play the regular version of the movie (the player).

I didn't say it would be in 3D. I clearly stated it was a 3D version of the film (on bluray) being watched in 2D.

So you're saying a 3D version of the film has exactly the same frames the 2D version has, PLUS the the alternative 3D view frame too?

So a 3D film has twice the amount of frames as the 2D version?
rboster's Avatar rboster
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Thread moved to the proper forum
rdgrimes's Avatar rdgrimes
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On those releases where 2D and 3D are on separate discs, they are not the same. 3D is mastered differently with boosted color, brightness and white levels, different framing, etc. Watching a 3D disc in 2D will get you one "eye" from the video, but will not look the same as the 2D disc.
gregzoll's Avatar gregzoll
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Again, if you play a 3D movie on a BD player that is only capable of 2D, it will only play back in the 2D version that is also on the disc. It is not going to playback the 3D version, because the technology is not there in the player.
NeilF's Avatar NeilF
07:08 AM Liked: 10
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Quote:
Originally Posted by rdgrimes View Post

On those releases where 2D and 3D are on separate discs, they are not the same. 3D is mastered differently with boosted color, brightness and white levels, different framing, etc. Watching a 3D disc in 2D will get you one "eye" from the video, but will not look the same as the 2D disc.

But that aside, the 3D version, viewed in 2D, with match a regular 2D version frame for frame?

And the 3D version will have twice the number of frames as the 2D version. ie: The same frames as the 2D one, + the alternative angle/eye frame for each one?

So a 1 second piece of film will have say 24 frames on the 2D version, but 48 frames for the 3D version?
Josh Z's Avatar Josh Z
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Quote:
Originally Posted by gregzoll View Post

Again, if you play a 3D movie on a BD player that is only capable of 2D, it will only play back in the 2D version that is also on the disc. It is not going to playback the 3D version, because the technology is not there in the player.

That isn't what he's asking. There's no need to repeat yourself with information he doesn't need.
Josh Z's Avatar Josh Z
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Quote:
Originally Posted by NeilF View Post

But that aside, the 3D version, viewed in 2D, with match a regular 2D version frame for frame?

Not necessarily. The 3D versions of some movies enhance the 3D effect by adjusting the position of images or layers in the frame. If you watch just one of those eye views, that will indeed give you a 2D version of the movie, but not exactly the same one as the official 2D release. Also, as someone else said earlier, the 3D transfers sometimes have boosted brightness and color in comparison to a dedicated 2D transfer.

Quote:


And the 3D version will have twice the number of frames as the 2D version. ie: The same frames as the 2D one, + the alternative angle/eye frame for each one?

So a 1 second piece of film will have say 24 frames on the 2D version, but 48 frames for the 3D version?

It's not an exact doubling of the data. The second eye view contains a lot of redundant information that gets extracted from the first eye view.
nikonf5's Avatar nikonf5
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Quote:
Originally Posted by NeilF View Post

So a 1 second piece of film will have say 24 frames on the 2D version, but 48 frames for the 3D version?

I think I know where this is coming from.

You want to know whether a 3D BD has lesser video quality because you think a fixed size limit on the BD disc [currently 50GB] means the studio had to lower the video quality to accomodate twice the data you are assuming is needed for 3D [L & R eye].

First, to answer your question, the answer is no, the 3D version is till 24fps [technically 23.976 fps but thats another thread ]

Remember, 3D is frame-packed so in the timespan where only one 1920x1080 frame would be sent out in 2D [approximately 24th of a second], one large frame is sent out in 3D.

This large frame is two 1920x1080 frames sitting one on top of the other with a 45-pixel height black image in the middle resulting in one 3D frame having a dimension of 1920x2205 [1920x2160 + 45]

Now, although the large 3D frame is still sent out at 24fps, the question of storage still comes into play.

The BD spec engineers realised that if they stored the extra second frame for 3D with the same compression they use for the one 2D frame, they would not have enough space on the disc so they decided to store the information for the other eye as difference data, meaning only the differences between the frames are stored and used to generate the information for the other eye which is done by the player.

This allowed for much less storage space being needed and, thus, the quality of the 3D video is the same as the 2D version.

Keep in mind that the brain will perceive higher quality on 3D releases because each eye gets its own separate 1080p image but this is not what you were asking out, at least not to me.
NeilF's Avatar NeilF
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^^ Nice reply thanks!

So basically if I was to watch a 3D bluray in 2D, it's not really inferior to a dedicated 2D version. eg: If I were to watch say Avatar 3D in 2D, or a dedicated Avatar 2D bluray, I'd not really notice any difference in image quality etc...

And thanks to the beautiful techinical description above, I now know that both left and right images are stored on the bluray (& sent to the TV), but due to some clever compression of the second image (only containing the differences) it doesn't use anywhere near twice the data as a 2D version.

Thanks
Lee Stewart's Avatar Lee Stewart
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Technical overview

Quote:


Multiview video contains a large amount of inter-view statistical dependencies, since all cameras capture the same scene from different viewpoints. Therefore, combined temporal and inter-view prediction is the key for efficient MVC encoding. A frame from a certain camera can be predicted not only from temporally related frames from the same camera, but also from the frames of neighboring cameras. These interdependencies can be used for efficient prediction

http://en.wikipedia.org/wiki/Multiview_Video_Coding
cakefoo's Avatar cakefoo
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Some 3D versions are ever so slightly brighter and more vibrant, and some 3D movies- if they're 3D animation- can tweak the foreground slightly more in focus, like Tangled. Those are the only kinds of differences I'm aware of. Oh and sure, the bitrate has to make room for the second eye view, but as others have said the codec generates that second view much more efficiently because it already has a reference eye.
William's Avatar William
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Quote:
Originally Posted by NeilF View Post

^^ Nice reply thanks!

And thanks to the beautiful techinical description above, I now know that both left and right images are stored on the bluray (& sent to the TV), but due to some clever compression of the second image (only containing the differences) it doesn't use anywhere near twice the data as a 2D version.

Thanks

Also in Frame Pack the left image contains 100% of the pic info. The right image just contains the difference from the left for 3D. So in 2D you view the left only. In 3D the right info is "filled in" from the left to make the complete double size frame.
Joseph MAK's Avatar Joseph MAK
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Quote:
Originally Posted by NeilF View Post

^
So basically if I was to watch a 3D bluray in 2D, it's not really inferior to a dedicated 2D version.

Well, I am not too sure this is exactly true. As others said in this thread, 3D releases may be "enhanced" as compared to their 2D releases. In theory, left eye frames of 3D releases may not be identical to the corresponding frames in 2D releases.

The real question is whether it is "worthwhile" to purchase the 2D release if one already own the 3D release of a particular film.

Am I right or wrong?
kid97's Avatar kid97
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11-15-2013 | Posts: 6
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Quote:
Originally Posted by rboster View Post

Thread moved to the proper forum

Quote:
Originally Posted by NeilF View Post

^^ Nice reply thanks!


So basically if I was to watch a 3D bluray in 2D, it's not really inferior to a dedicated 2D version. eg: If I were to watch say Avatar 3D in 2D, or a dedicated Avatar 2D bluray, I'd not really notice any difference in image quality etc...


And thanks to the beautiful techinical description above, I now know that both left and right images are stored on the bluray (& sent to the TV), but due to some clever compression of the second image (only containing the differences) it doesn't use anywhere near twice the data as a 2D version.


Thanks
W
kid97's Avatar kid97
10:11 PM Liked: 10
post #17 of 20
11-15-2013 | Posts: 6
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Quote:
Originally Posted by kid97 View Post


W
When I watched avatar in 2d blueray picture quality looked horrible but when I watched the 3d version in 2d picture quality was much better and more clear. Ther regular 2d blueray looked actuly terrible. Why is that?
FilmReverie's Avatar FilmReverie
11:28 PM Liked: 73
post #18 of 20
11-16-2013 | Posts: 652
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Quote:
Originally Posted by Joseph MAK View Post


Well, I am not too sure this is exactly true. As others said in this thread, 3D releases may be "enhanced" as compared to their 2D releases. In theory, left eye frames of 3D releases may not be identical to the corresponding frames in 2D releases.


The real question is whether it is "worthwhile" to purchase the 2D release if one already own the 3D release of a particular film.


Am I right or wrong?


I think you are right and wrong. You are right that there can be differences but these nearly always come down to what the film maker wanted to be different.

I disagree about if the OP asking whether also buying a 2d version is worth it if you own the 3d version because near one every 3d blu-ray comes with a 2d copy as well. I also haven't come across a 3d blu-ray that was less detailed then the 2d release. In fact presumably because each eye is getting two 1080p images the 3d version to me always looks notably more detailed.
xhonzi's Avatar xhonzi
08:23 PM Liked: 11
post #19 of 20
11-18-2013 | Posts: 914
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Both eyes are receiving a full 1080p (barring displays that discard resolution from the stream)- though it's entirely possible that more bandwidth is used in the 2D version than in the left eye of the 3D version. Both discs are capped at 50GB, so a long movie (i.e. Avatar) might not be able to fit a 3D version with relative bandwidth to the 2D version. Titanic and The Hobbit (others?) opted to split the 3D movie onto two discs rather than shrink the 3D version to fit onto a single 50GB BD.

Often the elimination of commentaries, deleted scenes, etc. lightens the burden of the extra 3D content- so it may be a wash and the 3D left eye may be exactly the same stream as used for 2D...

Theatrically Avatar 2D was 2.40:1 and 3D was 1.85:1. I'm not sure about BD releases and I'm too lazy to look it up.

Someone mentioned Tangled aleady, where the depth of view is shallow in 2D and deep in 3D. This was an artiistic decision as the shallow DOF was desireable normally, but the deep DOF made the 3D better. Also, a lot of 3D Disney movies use 'windowing' which is fancy talk for moving the mask around, which looks normal in 3D, but might be odd looking in 2D.

For these reasons, Disney has primarily gone the route of disabling 2D viewing of their 3D discs in software, and giving you a 2D disc in the packaging.

All of that being said, I don't have much first hand experience watching 3D BD in 2D. Just a few titles here and there and those not watched very scrutinously.
Quote:
Also in Frame Pack the left image contains 100% of the pic info. The right image just contains the difference from the left for 3D. So in 2D you view the left only. In 3D the right info is "filled in" from the left to make the complete double size frame.

This is incorrect. The framepacked picture contains 2 full images. The way the streams are stored on the disc is another story, but the framepacked signal sent from the player to the display is 2 complete images.
Josh Z's Avatar Josh Z
03:13 PM Liked: 408
post #20 of 20
11-19-2013 | Posts: 20,285
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Quote:
Originally Posted by xhonzi View Post

Theatrically Avatar 2D was 2.40:1 and 3D was 1.85:1. I'm not sure about BD releases and I'm too lazy to look it up.

Theatrically, Avatar was distributed in at least four different versions. All 2D copies were 2.40:1. In 3D, it was distributed in both 1.85:1 and 2.40:1, with instructions that the theater should project whichever was largest on their screen. (I saw it in 2.40:1 3D.) A special 1.44:1 crop was also prepared for IMAX 15/70 theaters. I believe that was only 3D.

The Blu-ray editions (both theatrical cut and extended cut) are all 16:9 full-frame. However, in the supplement section of the Collector's Edition box set, you can see clips and deleted scenes from the movie with the original 2.40:1 framing that James Cameron actually composed for on set.
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