Stereoscopic 3D to the Home

Content producers, broadcasters, encoding specialists, and screen manufacturers are all engaged in developing 3D solutions to the home. Their motive is clear: 3D films gross three times that of 2D films at the cinema and the TV industry is looking to capitalise on this demand. Similarly, there is a drive from Hollywood’s big players to make more from its 3D films and between 50% and 60% of its revenues come from non-theatrical sources.

In December 2008 BSkyB held a 3D demo day in which it broadcast 3D content, including footage from the Ricky Hatton versus Juan Lazcano fight, using its existing HD infrastructure. BSkyB’s head of product design and innovation Brian Lenz said, “We thought the demo and the resulting press would help engage 3DTV manufacturers, and spur the industry on to make more content. This was a reason for us going public.”

BSkyB used standard encode techniques incorporating MPEG-4 and traditional satellite modulation technology to multiplex two streams shot for the left and right eyes and transmitted the combined signal via the HD transmission path to the Sky+HD set top box. The feed was then decoded by the 46-inch Hyundai LCD screen. The interlaced screen transmits 540 lines to each eye with odd lines viewed by one and even viewed by the other. Sky’s Chief Engineer Broadcast Chris Johns said, “Although each eye only sees 540 lines, the two pictures vary slightly, and the brain’s ability to combine the two unique images means the experienced resolution is closer to full HD than SD.” There are many ways in which a TV can decode an image but BSkyB adopted one that was compatible with the 50/60Hz transmission rate of its HD infrastructure.

Other companies working on broadcast transmissions include France Telecom, which is currently looking to simultaneously trial 3D coverage with its HD French premier league soccer coverage. Last May it broadcast the Roland Garros tennis tournament in 3D. The content was transmitted over a 3D live broadcasting channel using MPEG-4 compression and sent via its fibre access channel and its usual set top box.

Japanese broadcaster NHK began transmitting daily 3D content via its channel, BS11, last April. The broadcaster uses a similar infrastructure to that demonstrated by BSkyB, in that it multiplexes the two streams into one that resembles an HD stream in bandwidth.

Satellite transmissions specialist Arqiva has also participated in several demonstrations and head of product development Arqiva Satellite and Media Scott Rose said, “Wherever a broadcaster can transmit HD, it can also transmit 3D. What’s important is the business case, and most will architectures for 3D — particularly as they are likely to be only a couple of years into their depreciation.” Although most broadcasters will physically be able to transmit 3DTV, some have a better business case than others. The platform most likely to be able to monetise 3DTV would be pay TV using a bandwidth-rich transport system such as satellite, or fibre-to-the-home.

Display alternatives
3DTV can be viewed on several different types of screen, but can only be viewed on conventional 2D screens in Analyph format, which uses red and cyan colours to create the 3D effect. Disney, which has committed to producing all its future feature films in 3D, transmitted its Hannah Montana Best of Both Worlds 3D movie over the Disney Channel last October and 787,000 viewers tuned in.

An alternative to Anaglyph is Colorcode which was used on NBC in the US at the beginning of February to broadcast a 3D preview of the big-screen animated feature Monsters vs. Aliens on NBC. This replaces old red-cyan Anaglyph with an amber-blue colouring.

Most commentators believe however that Anaglyph doesn’t compare with 3D stereoscopic technology in quality. BskyB’s Lenz said: “Anaglyph can make the colours look washed out and it would not be the type of service we could offer on a premium channel.”

TV sets that have been manufactured to show stereoscopic 3DTV are not yet widely available but most manufacturers have developed or are developing solutions. Arqiva’s Rose said he believes 2009 will be a watershed year for these products. He said: “We should start to see the beginnings of a consumer market before the end of the year.”

There are some solutions available now, but they are limited. Around 2 million 3D ready DLP rear projection TVs have been deployed in the US market but the solution only accepts a TV signal from a PC and sales are dwindling.

Plasma TVs are well suited to 3D according to Chris Chinnock from the 3D@home consortium, and Samsung and Mitsubishi launched models internationally last year. Speaking at a 3D session at Broadcast Video Expo he said: “Manufacturers can easily clean up the phosphers and tweak the electronics slightly to 3D-enable their sets. Most are likely to do so in the near term because it is an inexpensive process.”

LCD 3DTV’s are more difficult to manufacture. There are several approaches, with the Micro-pol, available from Hyundai, JVC and others being closest to market. This technology is currently prohibitively expensive however, with a 42-inch Hyundai set costing approximately £2,200.

The numerous display standards are a big hurdle for manufacturers looking for a route to mass market. There are approximately 15 different ways of presenting 3D feeds including raw interleaved, checkerboard, sideby-side, page flipping or front sequential, over under and 2D+depth. Many of the standards bodies in the field are helping to determine which are the best of these standards for broadcast television and other platforms, SMPTE, ISO and IEEE and the Consumer Electronics Association (CEA) are just a few of them. Commentators believe it will take at least two years to find a suitable standard.

Most of the consumer displays in the medium term are stereoscopic 3D in which the viewer watches the screen using active or passive glasses. But manufacturers and broadcasters alike believe that autostereoscopic is the long term goal for 3DTV. This is content that does not require the viewer to wear glasses. Several autostereoscopic screens are currently being used such as Philips’ WowVX, but only in the business sector with digital signage and retail displays for example.

Encoding and compression
Standards bodies are looking at other parts of the transmission chain too, particularly in the areas of encoding, transcoding and compression. Manufacturers such as 3Ality and Sensio have gone to market with encoding solutions, but Arqiva’s Rose said “most products are still in their early stages.”

Although demonstrations have used existing compressions standards, work is being done to update these according to the specific requirements of 3D. Satellite operator Hispasat joined the I+D 3DLive project in February to study new technologies for compression and transmission of 3D. The project is co-ordinated by Spanish telco Telefonica whose IPTV service Imagenio is currently working with manufacturer Philips to create a 3D VOD proof of concept.

There are therefore many issues that the industry must iron out before 3DTV is commercially viable. One is likely to be how to create a standard or standards that rules out the fewest number of players. One example of a standard that could rule many broadcasters out of the market would be a super high definition ‘frame interleaved encode’ (a screen that alternates rapidly between left and right eye so that each eye sees the full 1080x1920 frame) such as that being championed by Panasonic which plans to market its own full HD 3D 1080p television in 2010. This display would support Blu-ray 3D which requires a 100-120fps playback (120Hz). The product is likely to see roll out before broadcast 3DTV, but could end up ruling a broadcaster with a 50/60Hz transmission out of the game.

Way forward?
Over the long term the best solution for all is likely to be a screen standard that can accommodate several different inputs thereby allowing 3D from premium broadcasters as well as free to air, IPTV operators, HD/SD and BluRay content to run through the same technology.

If as 3D@home’s Chris Chinnock predicts there will be approximately 28 million 3D and 3D ready TVs in the market by 2012 — and if standards bodies have been able to steer a sensitive but objective path for the market between now and then — uptake will depend on the availability of quality 3D content.

As BSkyB’s Lenz said, “It is working out how best to create content that excites us most.” And beyond the industry’s current technical obstacles is that genuinely exciting proposition — immersive and engaging 3D content to the home.

By Nicola Brittain, TVB Europe