3D – The great white hope?

If we’re to believe all we’re being told, there’s a new dimension about to be added to our world. 3D is no longer going to be solely the preserve of cinemas – we’re all going to be watching it. On telly. In our homes. Every day.
Now that’s fantastic news for all of us involved in the creation of programmes. New technology means new opportunities, new challenges and all that. And with Sky already doing test broadcasts of 3D footy, it must mean that the ball is well and truly rolling, so we’d better get tooled up and ready for all the new lucrative contracts that are bound to be coming our way…..
Or should we?
Just for a moment, spare a thought for the guy who’s eventually expected to foot the bill for all of this – the consumer. How does he feel about it all?

Joe Public – does he really want it, and will he really pay for it?

Well, on one level he thinks its great. To be able to see our brave boys (you know – the ones with three lions on their shirt and three hundred notches on their bedpost) missing the all-vital penalty in the quarter-final post extra-time shoot-out will be SO much more acceptable in 3D. Because now, whilst the ball still misses the back of the net, our viewer does at least have the excitement of seeing it burst out of the screen, whizz over his head and through the door behind the sofa, narrowly missing his long-suffering wife who’s begrudgingly knocking up some sandwiches in the kitchen!
Yes, the idea of 3D is definitely appealing – but at the moment that’s about all he punter knows. He probably assumes that to get it will simply be a case of sub-scribing to (yet another) digital service and maybe donning some weird red and blue specs.

New technology is marvelous, sexy-as-hell, but it WILL be the death of us….

So when he finds out that he’ll be forking out who knows how much for a shiny new (probably even bigger and maybe wider) LCD flat screen TV with the all-important “3D Ready” sticker, maybe – just maybe – he’ll begin to wonder whether the ‘magical’ 3D effect is really going to enhance his enjoyment of Neighbours, Jeremy Kyle or Red Hot Channel XXX all that much. Because it probably won’t end with just the purchase of a new TV. He’ll almost certainly have to be tooled up with special electronic glasses (the disposable cardboard red/cyan anaglyph specs are SO last millennium) to allow him to view programmes in 3D. And if the whole household sits round the TV all day like Jim Royle and his couch-potato family, he’ll need five or six pairs! (Quite what he’ll do about the fact that half of them need regular specs to be able to see the screen in the first place is unclear – will he have to persuade them all to move over to contact lenses?) Whatever, we’re looking at quite a substantial investment here, coming hard on the heels of an upgrade to full HD which in turn came hard on the heels of a move to flat panel technology. So our long-suffering customer has already got his credit card at melting point AND we’re in the grips of the aftermath of the biggest financial meltdown the world has ever seen – and will be for the next twenty years or so.
Hmmm…. just how appealing is this whole 3D thing now? There are those of us who believe that there is only so far we can be pushed. New technology is marvelous, sexy and desireable-as-hell, but will it be the death of us?!

Shooting for 3D – the challenge starts here!

To understand how to shoot for 3D requires us to understand how homo sapiens’ optical data gathering and processing works – after all, we see in 3D all the time (unless you’re Gordon Brown). Basically, We have two eyes, approximately two and a half inches apart. They both look at the same object/scene at the same time (unless you’re Marty Feldman) but each eye sees it from slightly different viewpoints. The further away the object, the less difference there is between the two viewpoints. The closer the object gets to your face, the more cross-eyed you become looking at it. Our brain takes the information from each eye and processes it in such a way that it can compute the relative distance of objects from the eye, endowing them with depth.

So to shoot for 3D, all we have to do is set two cameras up in approximately the same configuration as our eyes – and bingo – job’s a good’un! It’s slightly more complicated than that because we are going to be showing these images on a screen before our brains are to be given the job of processing the information. This means we have to decide the position of the convergence point (the point at which the left and right eye images align – zero parallax). Let’s imagine that we are looking at three people each standing at different distances away from us. If we set the convergence point on the person furthest away, the other two will appear to be in front of the screen. Set it on the closest person, and the others will appear to be behind the screen etc. Of course, even the early pioneers (back in the 1920s amazingly) realised that you could exaggerate the 3D-ness of things by playing with the distance between the two lenses (inter-ocular separation). Overdoing it meant that your brain began to melt under the strain of making sense of the excessive parallax, causing headaches and sometimes nausea too.
Provided the pictures are not being used for a live broadcast, there is another way that we can shoot for 3D. Instead of shooting two images that converge at a chosen point. we can shoot parallel images which we converge in post-production. This allows us to play with where the “screen plane” is in our shot, giving us flexibilty over whether objects appear in front of the screen or behind it. Shooting parallel reduces the chances of excessive parallax (thereby reducing the importance of pharmaceuticals in our pursuit of viewing nirvana) but does pose other problems for the post production team in the form of edge-of-frame discrepancies which, although solvable, are time-consuming and therefore costly.

At present the most common way of shooting 3D is to use a large-scale rig which allows two conventional HD cameras to be mounted side by side or one above the other (the latter arrangement making deft use of mirrors). All-in-one 3D camcorders will soon become available, however these are likely to offer limited 3D options due to the physical constraints of the chassis and control software.

When it comes to showing 3D TV images, there is an inherent and blindingly obvious problem. We have TWO images but just ONE SCREEN. What we have to do, therefore, is to somehow contrive to show both images at once and yet somehow ensure that one image only goes to your left eye, and the other only to your right eye.

The most popular approach to solving this problem involves alternating left and right images on the screen. Now conventional 2D TV pictures these days are screened at 25 or 30 frames per second. In order to show 2 images at the same quality, the frame rate has to be doubled (you can immediately see why you’ll be needing a new telly!).

The task of getting alternate frames to alternate eyes is solved by special glasses with built-in liquid crystal shutters that are synchronised exactly to your TV via a stereoscopic sync signal connector and an infra-red emitter. The glasses block any light to the right eye whilst the “left” frame is being displayed, and block any light to the left eye whilst the “right” frame is being displayed. This happens so fast that your brain cannot detect any flicker, so voila! 3D TV! (NB, it’s not quite this simple because there are two different types of glasses which work the opposite way round to each other, so you have to team the right glasses with the right emitter – why on earth everyone couldn’t have collaborated over something so simple I simply cannot imagine – but they didn’t!) Of course, if you don’t wear any 3D glasses, all you see is blurry images – so everyone that wants to watch the TV whilst 3D is being screened MUST have their own set of specs even if they only only have one eye, or they are unable to see 3D images (as a significant percentage of people can’t).

As you might expect, the manufacturers are still battling each other for supremacy regarding formats and specs of 3D TVs

Whilst Sony and Samsung are committed to the active elctronic shutter glasses route, LG have adopted a solution that is less expensive. They use passive glasses which feature individually polarised lenses. The TV set displays both images at the same time (therefore has less information to process) and is coated with a special polarising film. This combination produces the same net result – one eye seeing one image, the other seeing another. The drawback is that each eye only sees half the resolution of any given screen. The advantage is that both the TV and especially the glasses are much less expensive to manufacture. Indeed, there were suggestions in the press very recently that LG will be releasing a 47 inch 3D LCD TV later this year with an anticipated price tag of around £2,000.

Is there any way to view 3D TV without any glasses at all? YES… well, sort of – if you believe in LENTICULES

There are TVs which don’t require glasses for viewing; instead they incorporate minute cylindrical lenses known as lenticules over every pixel of the display. These lenticules are optimised to allow vision of adjacent pixels to left and right eyes only. A quad-HD resolution display can therefore display full HD resolution to left and right eyes, however there is a limitation with this kind of display: The viewing angle is very critical in order to see the image in 3D and there are only a limited number of ‘sweet spots’ where this is possible. In other words, if you have one of these displays your viewing position will be defined by the TV, not you, and the odds are that if you are in a sweet spot watching glorious 3D then the person next to you will be watching 2D as 2D as they are not in a sweet spot. Suddenly the active shutter spectacles are looking much more appealing than they were!

So we can shoot 3D and watch 3D – but how do we EDIT 3D?

3D programmes are edited in same way as 2D programmes… aren’t they? Yer, right! Let’s just think about this for a moment. We’ve got twice the amount of data (two full HD images) that we need to be able to see, make decisions about and manipulate. For the most part, whatever we do to our left eye stream we need to do to the right eye stream, so logically we should be able to edit our programme using one stream only and then simply tell our system to do exactly the same to the other stream. Once that’s done, we’ll output them simultaneously to an “HD ready” screen, stir in a generous helping of lenticules or active glasses and Bob’s your Uncle!

If only it was that simple! Remember we talked about shooting in converged or parallel formats? Well, especially for parallel images, there’s some critical stuff we need to do to the individual streams. Although the premier edit system providers like Avid and Apple have developed software that makes it possible for you to view left and right eye images in various configurations – side by side, over/under or in stereo (either interlaced or checkerboard as per the requirements of your chosen 3D display), they still don’t give you the the total control you need. During editing, images are displayed at half resolution, allowing you to view dissolves, fades and supers. However, transform effects such as wipes, resizes and compositing that requires the image to carry both eyes in the same frame will not be able to be viewed in 3D. Also, these systems do not as a rule offer depth grading tools, so you will have to use an external specialist stereoscopic 3D finishing system that incorporates sync alteration and convergence tools.
So Bob’s NOT your Uncle – yet!

In conclusion…

So, what’s the upshot of all this rambling? Will we really become a nation of born-again 3D glasses-wearing telly addicts? Much will depend on the quality of the programmes that are produced for us to watch. If TV falls into the same trap as Cinema did in the fifties and sixties with programme plots being hijacked by self-indulgent, larger than life 3D effects at the expense of decent scripts and talent, 3D will be doomed to failure. But even if it doesn’t, I’m someone who just can’t imagine bothering to put specs on to watch every-day television. Frankly, I’d rather have great quality HD content in 2D(or better still 4K) for the majority of the time with 3D reserved for very occasional special interest programmes, games and maybe important sporting events…. Like England winning the World Cup!

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