TranSPORT: 3D, 1080p Drive Innovation in Transmission Sector
Rising demand for next-generation services like 3D and 1080p television has meant challenging new terrain for the transport community in recent years. While the capture side of 3D and 1080p production has grown by leaps and bounds over the past three years, broadcasters have struggled to find efficient, high-quality ways to backhaul, distribute, and deliver this content to the home.
At SVG’s recent TranSPORT summit, a panel of transmission-sector leaders discussed their experiences with these exciting new technologies.
“These new formats offer increased quality, but they also consume increased bandwidth,” noted Richard Buchanan, VP of content operations and engineering, Comcast Media Center. “There are serious constraints on all [aspects of the transmission ecosystem] but especially on cable systems. There is only so much real estate out there, and the demand on that real estate is constant and continuing to grow. We know that there are [next-generation] assets out there, but to be able to do that through our existing systems and provide a quality experience to the end user is a real challenge.”
For 3D Transmission, It’s All About Being in Synch
As broadcasters and vendors learned during the 2010 FIFA World Cup, the most important element of 3D transmission is synchronization of the left- and right-eye feeds. At the World Cup, Ericsson worked with ESPN and several other companies to develop an automated solution to keep both signals totally in line without any latency.
“We were able to create a mechanism to guarantee a phase lock between the left and right channels so that you could bring both feeds back separately and then combine them totally synchronized,” said Matthew Goldman, head of compression technology, solution area, Ericsson. “There is an extra effort that needs to be done on the receiver side to phase-lock the two receivers. Once we were able to do that, then we are able to bring back a pure left and right feed to a facility like Comcast Media Center or ESPN. From there, they can produce whatever format they want, and they also now have a viable archival format.”
The Frame-Compatible Issue
Today, the majority of live 3D sports productions distribute discrete left- and right-eye feeds. However, due to various factors (most notably, cable and satellite providers’ bandwidth constraints), the 3D telecast is usually delivered to the home as a frame-compatible signal, which crams both the left- and right-eye feeds into a single frame in either side-by-side or top-bottom configuration. This results in loss of resolution and downgrade in the overall 3D experience for the viewer.
Goldman believes that, some day, headends will be able to use the same synchronization technology Ericsson helped develop for the World Cup to deliver two discrete feeds directly to the home.
“As technology moves forward, hopefully, we will be able to take a similar type of [method] and deliver a separate left- and right-eye feed all the way to the end user,” he said. “But we’re not quite there yet.”
1080p on the Rise
Major content providers like ESPN, Comcast, and DIRECTV have already experimented with 1080p production and transmission. However, the enormous bandwidth requirements necessary to transmit a true 1080p signal have hindered its development thus far.
“We’re doing a lot of research and experimenting [on 1080p] right now,” said Buchanan, “But I couldn’t tell you when or exactly how we’re going to get there right now.”
It is important to remember when discussing transport of 1080p that there are two very different types. 1080p24, which is used for Blu-ray disc and cinema needs, can be delivered uncompressed at 1.5 Gbps, meaning it can be transmitted through a standard HD pipe. 1080p50/60, the format used for live sports TV, can be delivered only in an uncompressed form at 3 Gbps.
“In order to carry that amount of information, you actually have to change your infrastructure, which is a major investment,” said Goldman. “High-motion sports demand that high frame rate.”
Nonetheless, transport-solution providers like NetInsight already deliver both compressed and uncompressed 1080p/60 in the U.S. on a regular basis.
“Obviously, if you’re doing uncompressed, you need some fairly large pipes, and those are starting to come about,” said Joe Lograsso, VP of sales, North America, NetInsight. “There are a number of providers that are now offering much more bandwidth than ever before. Over fiber, you can finally accomplish uncompressed 1080p. Just as easily, you can compress it using JPEG 2000 and get a very high-quality transport and delivery with very few artifacts.”
Even with interest in 3D and 1080p on the rise, even more-advanced production technologies have appeared on the horizon, including 4K, 8K, and Super Hi Vision, which will make its high-profile debut when the BBC delivers the 2012 Olympic Games in London to theaters throughout the UK. Super Hi Vision is said to offer resolution 16 times greater than HD.
Also coming soon is the next generation in compression standards. HEVC (High Efficiency Video Coding) is expected to be ratified by early 2013 and may be deployed in the field as early as few months later.
“There is a new compression standard coming out in the next two years, but there is no way it’s coming any sooner,” said Goldman. “HEVC is about half the bitrate of MPEG-4, which is about half the bitrate of MPEG-2. So you’re talking about a quarter of a bitrate of what many of us were used to a few years ago.”