The satellite industry is starting to feel slight tremors in the ground as the next generation of encoders is starting to make its presence known. While the encoder of tomorrow remains a bit of a mystery, everyone accepts the fact that whatever comes next must outperform MPEG-2. And there is a sense that the next step may not be any easy one in contrast to the early days of MPEG-2 a decade ago.
Yes, what we can do today from the standpoint of encoding is amazing. Can we push ahead further in this regard? Yes, but when and at what cost?
Moored out in the middle of the Black Sea this summer, the research Vessel Knorr, from the Woods Hole Oceanographic Institute, provided thousands of viewers at numerous locations a live feed of an archeological expedition. Under the leadership of famed undersea explorer, Dr. Robert Ballard, the daily undersea activities of "Expedition2003" were beamed back live via the Intelsat 707 satellite.
In the process, the Knorr transformed into a multimedia showcase, and multiple encoding platforms were deployed on land and at sea. The satellite feed flowed through the MCI teleport in Andover, ME, to EDS Digital Media Solutions' headquarters in Plano, TX, where a team from EDS made sure everything ran smoothly.
"The Black Sea project was quite interesting because all MPEG-2 and MPEG-4 video was sent via IP. We multicast and unicast both, and there were hundreds tuned into the MPEG-2 via Internet2 [Internet2 is the high speed version of the Internet used primarily by universities and research institutes], and thousands tuned into the MPEG-4 via the public Internet," says Rich Mavrogeanes, CTO, president and founder of Vbrick, which provided some of the codecs for this project. "There were also theaters and other venues displaying the video on large projection screens."
EDS was the primary systems integrator, and IDB Systems worked with EDS as the satellite systems integrator. A team from EDS was also onboard the Knorr operating the telecom links.
"What was unusual here was the fact that the downlink simply connected directly to the Internet2. The fact that the satellite uplink was on a boat floating around the Black Sea was unusual, too," Mavrogeanes says.
Saving Bandwidth Is Not Enough
For Rob Robinett, CEO of California-based Modulus Video Corp., the curtain is going up on a whole new era as far as video compression and encoding are concerned. For one thing, MPEG-2 or H.262 is essentially 10 years old, and in technology terms, as far as Robinett is concerned, that is archaic.
The memory size, so hotly debated when MPEG-2 was defined, is now considered so small that no chips (are) commercially available and decoders use memory several times too large," Robinett says. "Now, the focus is on keeping the signal clean prior to compression, or cleaning it up as part of the input stage of a compressor."
A new DVB-S2 standard is emerging along with H.264--aka MPEG-4 part 10, (MPEG-4/10), Advanced Video Coding or Joint Video Team--as well as an increased industry-wide interest in a broader deployment of 8-PSK modulation. According to Analyst Adi Kishore at Boston-based Yankee Group, aside from H.264 and DVB-S2, the other major developments in the encoding realm being discussed or applied are rate-shaping, local encoding and transcoding.
"Rate-shaping, particularly variable bit rate, allows operators to allocate bandwidth based on the detail in each frame," says Kishore. "Local encoding achieves a similar result in that it allows operators to re-encode content at a cable headend in the most efficient manner possible for their network. Transcoding simply takes in one format and puts out another, more efficient format. Each of these solutions either by itself or together can help reduce the bandwidth utilized on a network.
"From a hardware cost perspective, multichannel video providers must think about the millions of homes that have MPEG-2 hardware already in their living rooms. It is very difficult to just adopt a new technology even if it does save bandwidth," Kishore adds.
According to Peter MacAvock, executive director, DVB Project Office in Switzerland, DVB-S2, which is the next generation DVB-S system, expands far beyond the service capabilities and options of DVB-S.
"DVB-S was used for the broadcast of MPEG-2 transport stream largely containing video and audio. DVB-S2 has been designed for five different types of satellite broadband applications: broadcast services, like DVB-S, interactive services, contribution services and content distribution/trunking professional services," says MacAvock. "Thus DVB-S2 is no longer limiting itself to MPEG-2 video and audio coding, and is designed to deal with a variety of codecs consistent with the different applications areas possible."
For the consumer, DVB-S2's impact will be relatively limited, as MPEG-2 will continue to dominate. But there may be new services taking advantage of the significant gain in coding efficiencies offered by MPEG-4 /10.
"For the professional user, DVB-S2's impact will be more significant as the flexibility it provides means that coding technologies can be better adapted to the application area. Although in the short term, MPEG-2 is likely to continue to dominate here also," says MacAvock.
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