Michael Grotticelli /
02.26.2010
Originally featured on BroadcastEngineering.com
MPEG-4 compression makes significant contribution to Winter Games production

Most of the 835 hours of HD video images and surround-sound audio elements for this year’s Winter Olympics are being delivered between Vancouver, British Columbia, and NBC’s New York City headquarters via MPEG-4 AVC compression over fiber-optic transmission line (with a secondary satellite path for redundancy). This has significantly reduced transmission costs while maintaining high-video quality necessary to meet the network’s HD standards.

NBC editors in New York and at various locations in and around Vancouver are using these contribution feeds to post-produce highlight packages and long-form spotlight pieces on the athletes and the events. Dozens of systems from Ericsson, including MPEG-4 AVC HD encoders, multiplexers, modulators, IP adapters and professional receivers/decoders, are enabling the network to send two MPEG-4 AVC compressed HD feeds in the same amount of bandwidth that they previously sent one using traditional MPEG-2 technology during previous years’ Olympics coverage. The satellite feed is being compressed using the MPEG-4 AVC compression and DVB-2 8PSK coding to match the fiber feed.

Leveraging newly developed compression algorithms within the encoders, high-quality HD video is being sent during the games at bit rates lower than 20Mb/s. The Ericsson encoding systems (and two full-time Ericsson systems engineers) are installed on-site in Vancouver within the international broadcast center. Several Ericsson encoders are also installed onboard mobile production trucks stationed at Vancouver’s Grouse Mountain and Whistler Resort to cover certain downhill events. NBC editors and producers at the IBC in Canada as well as in New York are seamlessly using compressed signals from the trucks.

“The installation went off without a hitch and the systems have performed exactly as planned during the games,” said Matthew Goldman, VP of technology, Solution Area TV, at Ericsson. He added that the encoders and signal paths were staged in the United States a few months before, and then on-site a few weeks before the games began. “Although the use of MPEG-4 AVC technology certainly saved bandwidth space, the real requirement was that the video quality could not be compromised in any way. I've heard from our on-site team that everything is working as planned.”

One audio feature of the Ericsson EN8090 encoders that is being used extensively in Vancouver is called quad phase aligned audio (also used at the 2008 Summer Games in China), which allows audio mixing engineers to keep all of the multichannel audio elements in phase.

On-site in Vancouver, compressed video signals, usually sent using the ASI protocol, are also being sent using IP to move files more easily between production locations. Most of the online video content on NBCOlympics.com and Universal Sports.com are using these secure native IP feeds. This allows NBC staff to use IP-connected systems for increased productivity.

“Delivering high-quality contribution HD video feeds at less than 20Mb/s is very challenging,” Goldman said, “but the Olympics are always a good testing ground for all kinds of new technology, and these Winter Olympics have provided us with a great proof-of-concept that MPEG-4 AVC could be used reliably and get the job done. The Olympics is a real-time event, so there is no second chance. This proves that our equipment is high-availability and offers 24/7 zero-downtime capability.”

Aside from the Olympics, NBC also uses Ericsson as well as other companies’ compression and transmission technology at its 30 Rockefeller Center headquarters to deliver many of its network TV and cable properties nationwide for its daily East and West Coast feeds.



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