Sky Italy prepares for the 4K era (part two)
Taking the long-view on the emerging 4K technology, Massimo Bertolotti, head of innovation and engineering at Sky Italy, remarks: “The 4K-UHD technology in practice should not be considered exclusively as ‘the most beautiful pixels or more pixels’; [it] will have a future if it can [represent] a whole new viewing experience that can be proposed to the viewers.”
After shooting the first Ultra HD 4K events (the Ferrari Challenge in March and a football game in April), the second part of 2013 was devoted to moving and managing the content, since this type of production involves a far larger amount of data than today’s full HD signal.
After several tests, the orientation of the research team led by Massimo Bertolotti was the same adopted by all other research groups – that is, to carry four synchronous signals in HD. Subsequently, during summer 2013, various tests involving sports contribution images were undertaken with the support of Eutelsat, Globecast, Ericsson and NewTek. Here the focus was on what was the best way to get the ‘trade-off’ or the optimal use of available bandwidth, in proportion to the quality and stability of the signal. At the heart of it all was the idea of using a standard contribution satellite without having to develop fresh solutions.
“The current situation is that there are still several parts missing in the 4K-UHD production chain. Or, in other, words there is still no standardised complete ecosystem in the wake of what is the case today for HD,” remarks Bertolotti.
“Thus, for the following event, Moto GP Misano Adriatico, held in conjunction with the IBC Show in Amsterdam, we showed up no new technologies: three cameras and an HD Kahuna Snell mixer to broadcast eight hours per day the incoming images from the cameras.”
In practice, the technology is there but the entire ecosystem is not ready yet.
At this moment it is impossible to think of transmitting any content or 4K Ultra-HD with H264 encoding, because this signal at the required bit-rate would be too big to handle both via satellite or cable.
The possible solution could be the new HEVC or H265 codec. Unfortunately, this solution was ratified as a standard only in early 2013, and has not yet been widely adopted for use in real-time encoders. Meanwhile, the actual end-cost of delivering the 4K signal remains a subject of considerable debate.
“In practice, it still takes time and a bit of “common effort” to try to find a standard layer that can facilitate the growth and spread of this ecosystem,” notes Bertolotti.
In fact, the frame rate and the greatly increased resolution could be the big issue and could lead to the creation of a new “visual language”, perhaps allowing the placement of cameras in particular locations that are not currently available with HD – including very close to the field.
Summing up recent developments, Bertolotti comments: “At Sky Italy, through live events, we have been able to propose a very good quality [for 4K, while] several tests on H265 HEVC are being carried out in order to understand what might be technologically the right [approach] to be followed for delivering [this new technology].”
Using Thomson equipment, the Sky Italy research team conducted a number of significant tests. The results were encouraging, suggesting that bandwidth usage with the use of HEVC 265 codec to compress 4K images could be very reasonable, around 12-14MB.