Editor's Note: Each Friday, High-Def Digest's own HD Advisor will answer a new round of questions from our readers. If you have home theater questions you need answered, send an email to HDanswers@gmail.com.
Answers by Joshua Zyber
Native vs. Simulated 3-D
Q: I have been reading various articles that claim in order to receive a 3-D picture on your TV, one needs a 3-D TV, a 3-D Blu-ray player, and preferably an HDMI 1.4 capable receiver. So, recently I purchased a Samsung 58" 3-D TV (model PS58C7000YF), and a Samsung 3-D Blu-ray player (model BD C6900). The 3-D player is connected directly to the 3-D TV by an HDMI 1.4 cable, and the audio is connected to my HDMI 1.3 capable Marantz receiver via an optical cable. The 3-D image displayed was in my view sensational and up to reported standards. (The Blu-ray disc was Monsters vs. Aliens 3D'.) I then played the same 3-D Blu-ray in my Sony PS3 connected to the Samsung 3-D TV via a 1.3 HDMI cable. To my surprise, I had the same perfect 3-D image as displayed via the Samsung 3-D Blu-ray player. I then played a variety of 2-D Blu-ray discs via the Sony PS3, and again to my surprise I had a perfect 3-D image displayed on the Samsung 3-D TV. (In all the above examples, the TV was set to 3-D display.) It would now appear that in order to display a proper 3-D image, one only requires a 3-D capable TV and not an HDMI 1.4 capable Blu-ray player or receiver. Can you throw any light on this development?
A: What you're experiencing here are actually two different forms of 3-D: real and simulated. Samsung 3-D TVs have the ability to convert any 2-D image into simulated 3-D. Think of it like colorizing a black & white movie.
Real 3-D movies, the kind that were actually filmed with 3-D cameras, photograph the action from two slightly different angles simultaneously. (Animated movies have the action rendered from two angles.) When these two different angles are displayed together, so that one image goes directly to one of your eyes and the other image goes directly to the other eye, your brain combines them into a three-dimensional picture. 3-D Blu-rays contain both views and transmit them both to a 3-D TV. What you're seeing with a 3-D Blu-ray (like that special 'Monsters vs. Aliens' disc) in a 3-D Blu-ray player is a full representation of what was photographed or animated.
When you play that same 3-D Blu-ray in a normal 2-D Blu-ray player (such as the PS3 with its current firmware), the machine can only extract one of the two camera views, and will only transmit a standard 2-D image to your display.
As mentioned, some 3-D TVs use special processing algorithms to simulate a second camera view from any 2-D image. We'll discuss the quality of that in the next question.
2-D to 3-D Conversion
Q:I hear that many of the 3-D televisions offer a feature to convert 2-D to 3-D. I understand that this is probably not going to be as good as stuff mastered in 3-D, and probably not even as good as studio 2-D to 3-D conversions, but just wondering how it works, and if it's any good. I am also wondering if certain material benefits more from the conversion, and if there are any criteria it has to meet? Specifically, I am wondering about home videos – the stuff I shot 20 years ago on VHS, 12 years ago on 8mm, the stuff I shot 10 years ago on DV, the stuff I shot 5 years ago at 640x480 with my camera, the stuff I shot last month in HD. (Of course, the concept of the handheld camera in 3-D is scary – I’ll bring the motion sick baggies!)
A: I'm going to stick with the analogy I gave above about colorizing a black & white movie. If a movie wasn't natively photographed in color, you – or, more realistically, the content owner – can try to simulate color photography by having the picture digitally colorized. In most cases, this will give you a rough approximation of what the movie would have looked like had it been made in color, but it will always stand out as fake and will never look as good as real color photography.
Converting 2-D to 3-D has much the same problem – especially when you're relying on the processing chip in a TV to perform this conversion on-the-fly. The digital effects wizards that Warner Bros. hired this past year spent millions of dollars and months of supercomputer rendering time to convert the recent 'Clash of the Titans' remake and 'The Last Airbender' (both originally photographed in 2-D) into 3-D. The results in both cases were universally panned for their atrocious quality. Now imagine what will happen when you expect your TV to do the same thing in real time.
In a best case scenario, the conversion may look OK. Movies like 'Monsters vs. Aliens' that were originally designed with 3-D in mind may convert pretty well overall. However, it won't be quite as refined or nuanced as the real thing.
I wouldn't expect much from material that wasn't ever made with 3-D in mind. Dimensionalizing your home videos may make for a fun experiment. You may even get a few striking 3-D effects out of it. But it's really just a gimmick, and shouldn't ever be thought of as anything more.
Polarized vs. Active Shutter 3-D
Q: There are a few TV manufacturers producing polarized 3-D technology for their displays. Do you think that 3-D technology is headed in this direction? I know that there are many barriers to using active shutter glasses such as ghosting, battery changes, and costs. All of these factors would be eliminated using polarized TVs. So why not focus on polarized 3-D as opposed to active shutter technology? Wouldn't the added cost to produce a polarized TV be offset by the cost of active shutter glasses? Or do polarized TVs have reduced resolution?
A: Actually, almost all 3-D TVs use active shutter glasses. LG has announced one passive polarized 3-D TV for the UK market, but I'm not aware of any other manufacturers offering this yet. Polarized 3-D is generally more suited to front projection. Most 3-D movie theaters project polarized imagery, as do a few models of home theater projector. Yet when it comes to LCD, DLP, or plasma TVs, the active shutter technology has proven more reliable.
Passive 3-D has a few advantages. As you note, the glasses are cheaper, smaller, and don't require batteries. Because the two polarized images reach your eyes simultaneously (as opposed to alternating between left and right, as active 3-D does), they're also less prone to ghosting artifacts or flicker.
But passive 3-D is also more difficult to implement. While the polarized glasses themselves may be cheaper than the active shutter variety, that doesn't necessarily mean that the rest of the display will be. Special screens are required in order to maintain the polarization of light. With front projection, silver screens are used. Unfortunately, these tend to have adverse side effects when displaying traditional 2-D imagery. I'm not sure how (or if) LG has gotten around this with the passive set they've announced.
As with any competing technologies, I'm sure that active and passive 3-D will each have their pros and cons. We'll have to judge the specific implementations of either on a case-by-case basis.
HDMI 1.4 and the PS3
Q: I've heard Sony is going to release firmware for the PS3 to enable 3-D games and Blu-ray playback. How can they do this if the PS3, especially the early models, are not equipped with HDMI 1.4, which is needed for 3-D Blu-ray?
A: My understanding is that the version of HDMI that Sony uses in the PS3 lacks certain features required for compliance with the v1.4 standard – such as the Ethernet channel or Audio Return channel – but meets other requirements that will enable 3-D video transmission.
Sony has already updated the PS3 for compatibility with 3-D video games. The firmware update that will offer 3-D Blu-ray playback will be rolled out in October.
IMAX 3D and DMR
Q: A while ago, someone asked you a question about how 'The Dark Knight' could appear soft on a giant IMAX screen. You said that the process to upconvert a normal Hollywood movie to IMAX involves edge enhancement and DNR. I don't entirely disagree with you, though I'll admit I was floored when I saw 'Superman Returns' in IMAX. (Less so with 'Spider-Man 3'.) There's a couple things your answer does not clarify. First off, what about IMAX 3D? A lot of movies these days are in that format, and some exclusively so. So what would you say to the "enhancing" of a scene converted to IMAX 3D, like the opening to 'Harry Potter and the Half-Blood Prince'? I'm sure that mapping 2-D footage onto a 3-D model with a virtual camera (I'm assuming that's what happens in the conversion) involves work. So what would you say about involve edge enhancement in that?
A: The two issues you're asking about – the IMAX DMR process of upconverting standard 35mm Hollywood movies to play on IMAX screens, and IMAX 3D – are two very separate topics. DMR upconversion entails adding Digital Noise Reduction and Edge Enhancement to the original picture, regardless of whether the imagery is 2-D or 3-D.
IMAX 3D projection, in and of itself, does not require any special digital processing. IMAX 3D works by projecting two strips of film through separate lenses in a giant projector. The two strips of film contain the left and right eye views for a 3-D picture. How that movie got to be 3-D in the first place is no different than any other form of 3-D. Either the movie was photographed that way natively, or was digitally converted (e.g. 'Clash of the Titans').
Your description of the way that 2-D footage is converted to 3-D is fairly accurate. This conversion doesn't necessarily require any DNR or artificial sharpening. However, if the movie is to be projected on an IMAX screen, it will have to undergo IMAX DMR, which will add them at that stage. This is unfortunately one of the basic principles of how the IMAX corporation has chosen to display 35mm movies on its screens.
As has been mentioned in previous articles, most brands of 3-D TV will have proprietary 3-D shutter glasses that won't work with other brands of TV. However, one reader made an interesting observation while demoing some 3-D sets at a retail store.
3-D TV Demos
Reader: I have looked at 3-D displays at two different stores. My favorite so far is the Panasonic plasma. The glasses do not seem to have the weird blue tint that there is on Samsung. However, I did notice something interesting. The Samsung glasses worked on the Panasonic display – for about 3 seconds, until they lost their sync. The Panasonic did not work on the Samsung – I lost sync the moment I looked away. That being said, the Panasonic seemed to resync faster. Sadly, the Panasonic seemed to have to be watched more of in a sweet spot than the Samsung did. Also to note, if you get to the stores and get to see the demo model, ask to see the Grand Canyon demo. WOW! Much better than any animation they show!
Check back soon for another round of answers. Keep those questions coming.
Joshua Zyber's opinions are his own and do not necessarily reflect those of this site, its owners or employees.