Contribution Network Priority for 3DTV
There are no barriers to Pay TV operators who want to follow DIRECTV and BSkyB by launching 3DTV services. Side-by-side 3DTV (full HD shared between both eyes) does not require new set-top boxes so the customer premise burden falls on subscribers, who need to buy a 3D television set. The transmission bandwidth premium is limited so there is no immediate need for a new generation of compression solutions for the last mile.
Those are the views of Benoit Fouchard, Chief Strategy Officer at compression vendor ATEME , whose company provides a range of contribution and headend MPEG-4 AVC encoders. However, ATEME is looking at how compression in the contribution networks needs to change, and Fouchard says this is where the R&D priority is today.
“The natural evolution for 3DTV services is to deliver side-by-side 3D content into the customer home but in the contribution network start to migrate from side-by-side to full 3DTV with two separate, fully synchronized 1080p50/60 HD channels fed back from an outside broadcast to the broadcast facility,” he explains.
The higher quality 3D content could be used to deliver full 3D to outdoor venues and retailers. Both these ‘business-to-business’ distribution outlets expose the benefits of 3DTV to the public so there is a good business case for providing the higher quality, with extra bandwidth. Fouchard points out that relatively few set-top boxes are needed to cover these distribution points so the introduction of a new generation set-top box on this limited scale is viable, especially if the Pay TV platforms can earn revenues from the outdoor venues (e.g. pubs).
Beyond major movie releases, ATEME expects 3DTV broadcasts to be limited to high profile premium content like World Cup soccer, and even then only the biggest games. Because of the production costs it could be several years before popular TV shows are aired in 3D and broadcasters will be taking a long look at 3D TV set penetration figures before committing.
It is the premium nature of 3D content and its general scarcity that removes the pressure from the transmission network in the short-term. As Fouchard points out, “If you already have a large HD offering, adding a channel of 3D, even using two streams of 1080p HD, is not a great burden when you consider the marketing impact that it achieves. So in the short-term, transmission bandwidth is not an issue. In the long-term it is a totally different story and then you have to refer back to the 3D TV penetration forecasts and think about changes in compression.”
ATEME predicts that for full 3D MVC (Multiview Video Coding), where a single stream combines full frames for each eye temporally interlaced, there will be enough temporal and spatial redundancy between the different views to ensure that bandwidth is never doubled. Fouchard says a 70-80% bandwidth premium is a reasonable expectation at this stage. And of course, consumers may be prepared to pay extra for 3D television.
One of the immediate R&D requirements for ATEME, looking at 3D contribution, has been to reassess the way it analyses compression performance. Fouchard says that when handling 3D content, this needs to move away from machine scoring to subjective scoring based on how the human brain reacts to 3D effects. “We are having to reconstruct our psycho-visual models based on 3D perception,” he reveals. ATEME has already found that some of the visual effects that work well in two dimensions, like blurring in relation to fast motion, become a problem in 3D. For example, blurring cancels the 3D effect.
Fouchard believes one of the main drivers for the deployment of 3D television by Pay TV operators will be to ensure they can match what Blu-ray disc players have to offer. “They will be keen not to relinquish ownership of 3D in the home. The same rationale is leading to the availability of 1080p HD movies in VOD libraries,” he says. “The message to consumers is that you do not need a Blu-ray player to enjoy 3D content after it has been in the cinema. I think 3D will also be part of a strategy to position entertainment for the home as opposed to entertainment out of the home.”
By John Moulding, Videonet
