Compression 2003: MPEG-2 & Beyond
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.
There Is No Pure Encoding Approach
The attempts to squeeze more from existing bandwidth and to offer operators cost-savings via lower bandwidth alternatives, which can perform the task at hand without sacrificing video quality in the process, are finally paying off. "We definitely see a trend in the market from MPEG-2 to MPEG-4. All of the major networks are interested in this both for SDTV [Standard Definition Television] and HDTV [High Definition Television] encoding," says Ovadia Cohen, vice president of marketing at Israel-based Scopus Network Technologies.
With the current emphasis on grooming, or comprehensive rate shaping, and local encoding, among other things, Scopus is supporting its customers by providing a broad array of products as part of its Intelligent Video Network concept. Along with its Codico line of Standard Definition (SD) and High Definition (HD) encoders and multiplexers, which can also perform stream processing, Scopus also introduced its IVG 7000 (Intelligent Video Gateway), a 1RU solution installed at cable operators’ master headends.
The IVG offers a scalable way to engage in video routing and processing, advanced video processing for MPEG protocol conversion, Dynamic Session Allocation and seamless Digital Program Insertion. In addition, optimal bandwidth allocation is achieved using rate reduced digital turnaround services. The simultaneous control of local encoders in defined statistical multiplexing (stat mux) groups is also a feature.
Many recent demonstrations have raised eyebrows. One involved Tandberg Television Inc.’s EN5920 real-time hardware encoder, Panamsat’s Pas 9 satellite and two video feeds from CNN International encoded over Digital Audio Broadcasting (DAB) via Windows Media 9 Series Video 9 (WM9) at 150 kbs, along with four audio feeds from Capital Radio Group.
Using standard QPSK modulation, dual Digital Video Broadcasting (DVB) and DAB streams were uplinked by NTL from the United Kingdom to Las Vegas via Pas 9. The IP encapsulation and multiplexing of the DAB audio and video sources were performed on Radioscape hardware. In Las Vegas, one video feed was downlinked, decoded and re-transmitted over DAB for display on a Windows XP PC, while another 1.5 Mbs DVB video feed was decoded by a satellite receiver card within a Windows XP PC and then presented on a large plasma screen.
While the interest in MPEG-4/10 has been growing, questions remain about when it will become a reality. "You cannot overlook the fact that no hardware-based realtime fully optimized MPEG-4 /10 encoders will be available for at least two years," says Lisa Hobbs, director of marketing at Tandberg Television. "Some think that a three or four year span is more realistic to achieve substantial advances over MPEG-2 performance and to achieve the same level of interoperability enjoyed today. At the same time, software-based encoding via a PC has limited appeal at best in the broadcast sector."
Tandberg is building equipment for WM9, and the EN5920 encoder can have encoder cards for both WM9 and MPEG-2 in the same unit. Tandberg will also build equipment for MPEG-4/10 when the standard is finalized and silicon becomes available.
"WM9 is a viable solution for customers with high quality, very low bit rate requirements in the next 18 to 24 months, because it is available now and can provide both a bit rate and performance advantage over MPEG-2," says Hobbs. "There could be slight coding quality differences between the WM9 and MPEG-4/10 systems depending on the material being coded, and MPEG-4/10 will likely become a predominant international standard in the future."
Meanwhile Downstream: A More Challenging Task
The encoding solution in itself represents just one link in the chain. As the number of encoders, statistical multiplexers, demultiplexers, switches, routers, servers and other essential pieces of hardware grows across the entire expanse of the network in question, the service provider or cable operator needs a better way to pull the entire system together.
"The operators today are increasingly reliant upon interoperable, multi-vendor systems that are heavily automated. These systems are tied together with sophisticated scheduling, traffic, billing and other back office support tools," says Paul Haskell, director of the encoding technology engineering team at Harmonic Inc.’s Convergent Systems Division.
Harmonic has a wide range of customers including market leading DBS providers like DirecTV, which recently upgraded its encoders and statistical multiplexers with Harmonic’s DiviCom MV 50 ultra low bit rate MPEG-2 encoders and MediaNode MN20 Multiplexer with DiviTrackXE statistical multiplexing. A good example of a recent DTH startup customer is Skylife in Korea, which has deployed DVB-MHP (Multimedia Home Platform) using a Harmonic digital headend, along with the VideoGuard conditional access system from NDS Ltd.
Along with its MV 50 and MV 400 HD encoders, Harmonic recently rolled out its NMX Digital Service Manager with the objective of enhancing both the degree of control that service providers have over their DTV and HDTV headend infrastructure, while also making the whole process of monitoring the environment in question more user friendly and efficient. The NMX also provides system statistics in the video-on-demand environment, which are important both operationally and financially.
"The NMX pulls the entire system together, and drives it operationally in a way that typical network management systems cannot. Designed to put more power behind the operator’s video services, NMX means the only thing the customer needs to worry about is what the service-level input and outputs should look like. Beyond that, all the configuration and provisioning are taken care of by the NMX," says Haskell.
Changing The Landscape
The TV world is going through a major shakeup, and encoding decisions are playing an important role in the process. The business models driving HDTV, PC-enhanced TV viewing– hands on the keyboard, eyes on the screen–Personal Video Recorders (PVRs) and VOD are all influenced by what encoders are in place. As we witness a blurring of TV behavior on the consumer side, there is a sense that the content players and service providers have to be very careful if they do not want to be left behind.
"We believe we are at a formative point of HD development," says Paul Kosac, vice president of market development for the media networks business unit at Georgia-based Scientific-Atlanta Inc. "If I had a library of HD content, I would want to get it out there as fast as possible," adds Kosac. "Many content providers are optimizing satellite feeds, and are attempting to take advantage of the value in offering HDTV programs and multiplexes. As a result they get more distinctive shelf space."
For the roll-out of the Bravo HD+, NBC Cable Networks will use Scientific-Atlanta’s PowerVu digital video system, including the PowerVu Program Receiver Model D9850 decoder at affiliate cable headends. The Asynchronous Serial Interface (ASI) output on the D9850 can feed the HD signal directly to a QAM modulator for simple inclusion in the cable programming lineup.
Cablevision will operate this new PowerVu HD uplink system for NBC at the Rainbow Media Holding playout center on Long Island, NY, while network management, security, decoder management and remote access will be provided by the PowerVu Network Center.
"In the cable sector, the advent of high speed data, PVR capability and HDTV, including HD STBs [Set Top Boxes] with built-in PVRs is changing the whole landscape. As to future technologies, MPEG-4 has been in incubation for the past four years with various groups trying to figure out how best to apply it," Kosac says, adding that MPEG-4 /10 will be introduced into the market throughout the next 12 to 18 months.
As cable operators assess the role of PVRs in particular, MPEG-4/10 becomes more attractive. Using MPEG-2, a PVR with a 80 GB hard drive can hold almost two dozen MPEG-2 movies at 3.5 Mbs or a half dozen or so HDTV movies at 12 Mbs. Insert MPEG-4/10 into the mix, and the same PVR can hold almost five dozen movies at 1.5 Mbs and more than a dozen HDTV movies at 6 Mbs.
Opportunities Are There
While many readers are no doubt thinking that H.264 will remain firmly on the ground, Elliot Broadwin, CEO of iVast, sees a multitude of possibilities, including potential satellite plays, as companies large and small alike look for the best way possible to encode, author, deliver and playback MPEG-4 streams. Broadwin indicates that iVast is working on a professional 1RU H.264 receiver. It has also teamed up with H.264 hardware vendor Sand Video to pursue HDTV solutions.
"Besides HDTV, we see a number of different opportunities in the SNG point-to-point arena as well as in mobile broadcasting with companies like [Mobile Broadcasting Corp.] MBCO in Japan and SKTel in Korea," says Broadwin.
Later this year, Tokyo-based MBCO will launch Mbsat 1, an S-band satellite that will offer MPEG-4-based services throughout Japan at rates between 128 kbs and 384 kbs. Toshiba is manufacturing the MPEG-4 encoder and the multiplexer as well, while Fraunhofer is providing audio encoding software, according to Akihiro Sakurai, MBCO encoder and multiplexer system development leader. Some of the receiver vendors for this venture include Toshiba, Sharp and Alpine.
"The payload system on Mbsat 1 is a simple bent-pipe type transponder, and so it does not matter if the compression is MPEG-4 or H.264 or whatever," says Sakurai.
"While the United States is not as active in mobile broadcasting, the potential to push video and creative content over digital audio satellite networks such as XM Satellite Radio and Sirius has already been demonstrated," says Broadwin.
"For the SNG market, we are integrating write to disk so that a user can capture and repurpose material already in compressed format. As for mobile broadcasting, there is the whole satellite backhaul dimension," he adds. "We have already demonstrated sub 1 Mbs MPEG-4 over satellite with Swe-Dish."
In addition to MBCO and SKTel, iVast is looking to Asia where other deployments, especially IPTV advancements, also look promising.
"The headend model for IPTV is similar to the North American cable market with a lot of collection done via satellite, including international feeds outbound from the United States," says Broadwin. "People will wait for the right technology and the right standard. I see Asian and European network operators as more aggressive in terms of adopting new technologies in general like H.264 in the immediate future.
"In North America, you see a lot of people who elected to wait it out as far as MPEG-4 is concerned. Now, HDTV has placed H. 264 on everyone’s radar screen. As for the large cable or satellite operators in the United States, there are no small deployments out there any more, just huge networks with millions and millions of existing subscribers," he adds. "The amount of planning and integration for the infrastructure upgrades of these immense networks is a lot more complicated today than it was for MPEG-2."
While rolling HDTV out has proven a little more expensive than originally expected, Kishore does not believe the encoding process is proving to be exceptionally difficult. Have any unexpected challenges been encountered at HBO in the process of encoding HDTV? "Nothing unexpected. It works smoothly," says Bob Zitter, senior vice president for technology operations at HBO Time Warner Entertainment in New York City.
HBO regularly updates and upgrades the Motorola Digicipher digital encoding equipment used on its linear networks, and the result is that video quality and compression efficiency have constantly been improving. For HBO On Demand, the encoding was changed to new equipment from Digital Vision, which has provided video quality improvement, according to Zitter.
"We are evaluating new encoding technologies that may be employed in the future. These include WM9 and H.264, which should be available in one to two years," says Zitter. "Whether these are ever deployed and for what purpose remains to be determined."
"Unfortunately with the delays to date of perhaps five plus years, HDTV and DTV are both being built on an obsolete technology and a modulation scheme designed for the impairments found in analog cable in the 1970s," says Robinett.
So much is at stake. A company could spend huge amounts of money at the wrong time or forego spending money at the right time and wind up well behind the pack. Encoding and compression are more than enabling technologies. They can make or break business models. Decoding all these signals is never easy. Be sure to check out the expanded version of this story on our Web site at http://www.viasatellite.com.
Peter J. Brown is Via Satellite’s Senior Multimedia & Homeland Security Editor. He lives on Mount Desert Island, ME.