Do you think 3D Broadcasting in its current format is likely to gain much market share?

Bob Pank#

Author: Bob Pank#

Published 1st January 2012


There are two issues that affect the potential growth of 3D in broadcasting: they are the widespread availability of 3D enabled devices, and the cost of producing and broadcasting 3D content. All HD TV sets from major manufacturers over 40 inches that are sold today include 3D capability, so the end-user market of 3D capable viewers is growing by default. 3D is not even a remarkable selling point any more for the latest TVs: if you take the Samsung Smart TV as an example, this is marketed as a connected TV - the 3D capability is advertised with just a small label on the box. So there is a growing potential market of viewers for 3D content providers.
On the other hand, there is a considerable obstacle to growth in the 3D market, and that is the lack of content created in 3D. With millions of 3D capable sets sold, even viewers of subscription television services can still on get a very limited amount of content. There are several Blu-ray movie titles available, but in general the amount of content is not enough to create a mass market for 3D. Perhaps the Olympics in 2012 will see mass production of 3D content, as was the case in the previous football World Cup.
How much do production and transmission costs affect potential growth?
There are two ways to produce 3D content: one - the approach taken by broadcasters like Sky, is to shoot live premium events such as sports and provide them as paid premium services. This is expensive, both in production, where large numbers of stereoscopic cameras are required, and in the cost of the contribution links. Other content providers such as National Geographic or Discovery are producing documentaries offline and post processing the video content for 3D with software, and this is an approach that can be afforded even by small broadcasters. It gives good results in terms of quality, and when the broadcaster has gained the skills necessary to shoot good 3D content, there is little further expense because almost all broadcasters already have the means to do the necessary post production.
Transmission costs for 3D can be another obstacle for the broadcaster. The current approach is to simulcast the same content in two versions: the 2D and 3D, dedicating a separate channel for the 3D transmission, and that extra channel is a cost the broadcasters can’t avoid. This method is out of reach for many terrestrial because simulcasting 2D and 3D transmissions require more bandwidth and terrestrial spectrum is a scarce resource.
Can new formats for 3D transmission help reduce these costs?
Yes, one benefit of new transmission formats will be cheaper transmissions for the broadcaster, and this will remove one of the obstacles to 3D broadcasting growth.
The format we have developed at Sisvel Technology allows the broadcaster to distribute a single piece of content that is both viewable in 3D and backward-compatible for 2D, allowing the broadcaster to use a single channel service to reach both audiences. The essential principle supporting this method has already been adopted in the standard proposed by DVB because the ability to transmit to both 3D and 2D viewers in the same channel is what European terrestrial broadcasters want.
Sisvel Technology’s 3D Tile Format is a frame-packing format, like the currently default standards, which are known as Side-by-side and Top-and-bottom. The 3D Tile Format allows two component images, the left and right images of the stereo pair, to be packed into a single HD frame . When the format is compressed using H.264/AVC, suitable signaling can be applied so that the 2D decoder can isolate from the frame packing format one of the two frames used for the display of 2D video, while at the same time the 3D decoder will understand that the signal carries 3D video and will provide the 3D decoding. The underlying technology has been already adopted by DVB in the Annex B of the specification where it specifies that the cropping rectangle feature of the AVC coding standard might be used to produce a backward-compatible 2D stream. Major European satellite broadcasters we are working with are already using this cropping rectangle feature to distribute backward-compatible 3D content, and by using the bandwidth for a single HD video stream they are reaching both audiences. The terrestrial broadcasters experiencing the format, such as Quartarete in Italy, are using it to mix 2D and 3D on the same channel – some 3D and some 2D is mixed in the schedule seamlessly, with users only noticing the start of a 3D content if they are equipped with a 3D decoder: others simply see 2D at all times.
What else does the 3D Tile Format offer?
Besides the save of bandwidth another advantage of the 3D Tile Format is the improved resolution. With the Side-by-side and Top-and-bottom methods, you have to reduce the resolution of the video either horizontally or vertically in order to squeeze the two into a single HD frame. The 3D Tile Format uses a different approach, composing two 720p frames (left and right) in a 1080p container. This does not require any loss of resolution because the area of the 1080p container is higher than the sum of the two component 720p video frames. The format only requires one of the images to be sliced into parts and this is reconstructed by the 3D decoder to make the left or right frame, while 2D decoders may discard it and use one of the frames for an HD 2D image. The key quality difference is that no information is lost in composing the packed format, so to reconstruct the 3D image, no re-creation of pixels is required – unlike in the other formats where half of the pixels have to be recreated, either by interpolation of extra pixels, or by scaling the size of the existing pixels, making rectangular pixels from the square originals. This technique introduces a lot of artifacts into the image and leads to a degraded picture quality.
The DVB Project is already working on the specification for the second phase of 3D broadcasting because many of the broadcasters transmitting 3D are not happy with current quality and are willing to adopt a better method for the next phase of the standard. The 3D Tile Format is one of the candidates for this new phase. There are others, such as MVC (multi-view video coding), the principles for which are included in an annex to the H264 specification. There is a drawback to this technology, in that MVC is able to encode the two views with full HD quality but broadcasters would have to carry two independent video streams across the production infrastructure, which is difficult for current broadcasters because of the use of so-called ‘single-wire infrastructure’. MVC would require doubling of the existing production and contribution infrastructure, which of course would entail a huge investment. Another approach may be the ‘frame-compatible compatible’ approach, currently under study by the MPEG consortium. The idea here is to use the existing frame-compatible formats as a base layer and then to encode several enhancement layers, so that existing decoders receive plain side-by-side, but new encoders will be able to detect and use the enhancement layers to make up the full HD resolution of the image. As with MVC, however, there is at least one major drawback: at this point there is no encoding standard efficient enough to make this approach feasible within the existing broadcast structures – you end up with a bitrate comparable with simulcasting two independent views. So it’s not attractive to broadcasters unless a new generation of encoding technology is developed to make it more efficient. (this also applies to MVC – it’s not that efficient). MPEG is already working on next generation encoding standards that will outperform current standard by 40 percent, but until this is available broadcasters are unlikely to adopt either standard.
Therefore the 3D Tile Format allows broadcasters to use their existing infrastructure, but delivers a better quality image. It’s therefore a good compromise that will allow the 3D broadcast market to grow organically, without requiring a lot of speculative investment up-front.
How and where is a new format likely to be adopted?
The idea of adapting broadcast technology for 3D originated at least 30 years ago, with the innovator Lenny Lipton laying the theoretical foundations in the 1980. These ideas become the current de facto standards of Side-by-side and Top-and-bottom. In recent years, the development of large LCD and plasma screens with fast refresh rates is the key enabler for 3D content distribution, allowing the presentation of the alternating frames at speeds fast enough to avoid causing flicker or other unpleasant effects. This has made 3D broadcasting feasible. The formats proposed in the 1980s were a practical solution, but not good enough to provide an acceptable image quality to the viewers used to HD.

There are also non-broadcast applications for the format. The 3D Tile Format is neutral in respect of networking technologies used for distribution, so it’s also applicable for VOD or distribution over IP networks. 3D content for portable gaming consoles is another market we are discussing with manufacturers.
One possible area of development for the future would be to allow the viewer to moderate the ‘strength’ of the 3D effect; some users find that 3D causes them headaches, and would feel more comfortable ‘dialing down’ the perceived amount of 3D. Enabling this feature would require some extra depth maps carried to the encoder together with video content, and with the 3D Tile Format, the black part of the frame could be used to carry this type of information.

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