Coming through a screen near you

2009 looks set to be the year for 3D, as industry leaders at the big consumer tech trade shows showcased their 3D content capabilities using TVs already available to consumers - E&T investigates.

The image of filmgoers wearing headache-inducing cardboard glasses as filtered red and green monsters leaped out of the screen is a thing of the past. 3D, originally a film-based experiment, has finally been cracked with digital processes and polarised light.

As a result of this glacially-paced revolution, cinema, TV broadcasting, gaming and even outdoor advertising are finally looking in depth at 3D display technology - especially as it has begun to establish itself as a successful reality rather than another false dawn.

For that dawn to represent the beginning of an era of 3D innovation, a whole set of issues need to be resolved. For starters, there is the requisite standards competition to officiate, in the grand tradition of VHS vs Betamax and HD-DVD vs Blu-ray.

Three main stereo 3D display technologies are in the running: active, passive and autostereoscopic. The first requires shutter glasses for use with Digital Light Processing (DLP) and plasma screens; the second requires polarised glasses; and the last requires no glasses at all. Each of these types take different input formats: interleaved, interlaced and checkerboard. Unsurprisingly, preferences differ, however many agree that certain technologies are standing out.

"Right now, shutter glasses give you the best experience because there is already an install base of millions of HDTV DLP screens and analogue cathode ray tubes, and these shutter glasses are also compatible with new 100/120Hz (UK/US) liquid crystal displays," says Andrew Fear, product manager, GeForce 3D Vision, nVidia. "In addition, shutter glasses allow you to have maximum stereoscopic 3D quality and depth, with no ghosting."

Engineers also agree that some challenges in the 3D world are universal. To make stereoscopic graphics viable, the first challenge was to find a way to encode 3D content for existing formats and interfaces.

"Typically, in engineering, the easiest way to solve a problem is to determine your parameters anew, rather than constrain to existing parameters," notes Matthew Chang, Dolby spokesperson. "That would be easier, but we believe that compatibility and avoiding making existing hardware obsolete is the best solution for the consumer. Thus, our engineers tackled the task of designing a system that does not use the 'start from scratch' assumption.

"We devised a solution wherein we could efficiently encode checkerboard content and produce a compliant compressed video stream (for example H.264) that has bitrates comparable to a 2D version. A typical blu-ray averages 20Mbps, with our technology; a 3D checkerboard encoded version can also be 20Mbps. Rather than devise a new format, by doing the hard work at the encoder and creating a H.264 compliant output, the rest of the system treats the video as if it were 2D. Therefore it can pass through the system to the display with existing equipment."

How 3D will be delivered

In essence, then, the backbone technology is already here and in living rooms. The next step is to decide how the content will be delivered. The starting options are becoming quite clear, as the infrastructure is already in place for movies and games via blu-ray or DVD, and TV broadcast through existing routes.

"Currently, the only way to distribute 3D content to people's homes is over the existing broadcast infrastructure, or using blu-ray or DVD…No special equipment is required," says Bill Foster, Futuresource Consulting's senior technology consultant.

But is there enough content to make 3D financially viable? It's a classic 'chicken and egg' situation, as many consumers are not picking up on 3D due to low content volumes. Providers are not producing much 3D because it's more expensive and the market is small. However this is changing. Film producers, such as Lionsgate, Pixar and Disney, are bringing more and more 3D movies to cinema screen, games developers are focusing on stereoscopic 3D and broadcasters, such as BSkyB and the BBC, are producing content in 3D for future broadcast.

Movies, in particular, are pushing the trend, with at least one 3D movie released each month. By the end of 2009 and into 2010, this output is set to at least double.

And that's just new content. It is also possible for films and games to be 'retrofitted' with 3D, the difference being that, with content originally created in 3D, the images appear to come out of the screen. With remastered content, the 3D image appears to be within the set itself, the difference almost being a concave/convex appearance.

A number of companies are already remastering existing movies into 3D, notably In-Three, whose flagship project has been a sequence from 'Star Wars', financed by the movie franchise's creator George Lucas.

This process is currently very expensive as much of the work requires manual intervention, but costs will inevitably fall as technology becomes more sophisticated.

"Frame-based re-rendering can deliver effective 3D from 2D content," says Chris Johns, BSkyB's chief engineer. "As computer processor speeds increase, this capability will evolve, but it is still labour-intensive."

Another company, DDD, has a process that generates 3D pictures from 2D 'on the fly'. The results are variable and highly dependent on the original content but, again, will improve over time.

Gaming, however, excels in this area as it has effectively been working in 3D since the release of more power hardware in the mid 1990s.

"Characters and world objects are modelled in 3D using software packages such as Maya and 3D Studio Max, from which they are exported and turned into a format that the game engine can understand. The object's position within 3D space has always been there in the game but until now it has been difficult to present the information in a user-friendly way," explains Tad Swift, PC engineer at Electronic Arts (EA).

Games can now be played in full stereoscopic 3D both on computers and consoles. For PC, gamers can use nVidia's package of glasses, software and graphics processing unit (GPU) to play over 300 pre-existing games in 3D, including 'World of Warcraft', 'Tomb Raider: Underworld' and EA's 'Burnout Paradise'.

"When a developer creates its game in 3D, it's already accounting for depth, models, and lighting, so all of that information is available to a GPU," says Fear. "What we do is analyse that 3D data coming to our GPU and have customised software that renders a left-eye and a right-eye view for each frame. We then synchronise it to the display and render the appropriate eye view based upon our glasses lens and LCD refresh rate."

Developers are also creating their own similar technologies to bring 3D gaming to consoles as well as PCs. These will be playable in 'full' 3D, straight out of the box via the PS3 or Xbox 360.

"Our games engine - BlitzTech - achieves the necessary speed, which is crucial in order to render every scene twice and we're learning lots of good techniques for creating 3D models that can be efficiently processed by the computer," says Andrew Oliver, co-founder and CTO of Blitz Game Studios.

"The game needs to be running at full resolution (1080p) at full frame rate (50/60fps) and then rendered with a left and right view. Most games run at 720p and at 25/30fps, and even then can slow down, so it needs more than a fourfold increase in speed. That's a big demand for developers."

Content is out there, and over the next 12 months will become more commonplace. With continued support from providers, 3D looks set to find its place in home entertainment as well as on the big screen. The acceleration will largely be driven by the advent of 3D films coming into the home, but with broadcasters continuing to shoot a range of programming in 3D as well 3D gaming becoming more prolific, the age of true 3D has finally arrived.

Specs of the specs

Shutter glasses are used in conjunction with a display screen to create the illusion of a 3D image. Transparent glass containing liquid crystal and a polarising filter becomes dark when voltage is applied. The glasses alternately darken one eye lens, and then the other, in synchronisation with the refresh rate of the screen, while the screen alternately displays different perspectives for each eye.

Polarised glasses create the illusion of 3D by channelling correspondingly polarised light from two superimposed images into to left and right eyes.

Autostereoscopic displays use lenticular lenses or a parallax barrier. If the viewer positions his or her head in certain viewing positions, a different image will be received by each eye, giving a stereo image.

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