HDTV means big pictures for viewers and big demand for encoders. More important, producing high-quality HDTV at lower bit rates leaves bandwidth available for networks to dabble in multicasting, data services, and other new forms of digitally delivered content.
But encoder demand isn't just about HD. New standard-definition encoders based on advanced compression schemes MPEG-4 and Windows Media 9 will also hit the market at NAB. Although initial demand for these compression schemes has been from telephone companies and cable providers, broadcasters will use them for such applications as electronic newsgathering (ENG) or sharing content between stations.
On the HDTV front, Tandberg Television will demonstrate the ability to statistically multiplex HD and SD feeds together in one ATSC bit stream. The company will also show two HDTV encoders designed for digital satellite newsgathering (SNG): the E5784, a 4:2:0 version aimed at news applications, is priced at $61,000); the E5788, a 4:2:2 version suitable for sending signals from remote events back to the station, is priced at $78,000. The integrated units have three modulation options (QPSK, 8-PSK, and 16-QAM) and an SNG remultiplexing card, according to Director of Marketing Lisa Hobbs. The card allows multiple remote feeds to be sent back to the station as one. Tandberg has already sold two SNG units to a production-truck vendor.
Tandberg will also introduce its Intelligent Compression Engine (ICE), a platform that will support all future Tandberg encoders regardless of compression format. The first ICE encoders will be the EN5930, a professional-quality SD encoder for MPEG-4 part 10, and the EN5920 encoder for Windows Media 9 (the VC-9 profile as submitted to SMPTE for standardization); both are priced in the $42,000-$45,000 range. The EN5920 has already been selected by Swiss telephone company Swisscom for a trial of interactive-TV service over an IP broadband network.
Tandberg also sees the benefits of next-generation encoding techniques. Hobbs estimates that Windows Media 9 and MPEG-4 can offer a 20%-50% improvement in bandwidth efficiency for a given picture quality. But. since there is already a large embedded base of MPEG-2 set-tops deployed by cable and DBS operators, she expects to see WM 9 and MPEG-4 targeted more at new services like Swisscom. Before these compression schemes can be used for professional applications, professional decoders need to be built.
"Some customers talk about Windows Media 9 or MPEG-4 in a newsgathering environment," she says. "We are not ignoring those requirements, but there aren't any commercial decoders for the Windows Media 9 encoder. You would be using some kind of consumer device to do it."
Harmonic Inc. has seen a big increase in demand for HDTV encoding over the past year, says Glen Sakata, director of sales for broadcast and telecom. In December, the company began shipping its second-generation MV 450 HD encoders, which are priced about $45,000, to broadcast customers, including Sinclair Broadcast Group.
Sakata says the "radical shift" in HDTV-programming plans has spurred Harmonic to step up its HD-encoder development. That included bringing the company's "look-ahead" process—which combines image analysis, filtering, and noise reduction to maximize compression efficiency—into the HD realm.
Harmonic's SD encoders use three silicon chips, besides the encoding chip, to perform the "look-ahead process." Applying a similar approach to HDTV would have been prohibitively expensive. Advances in silicon technology, however, now allow Harmonic to perform look-ahead for HDTV on one chip, says Sakata.
Increased compression efficiency is becoming more important in HDTV encoding as commercial broadcasters add multiple SD program streams to their HD streams, which some PBS stations have done. Some even want to fit two 720-line progressive HD streams into a 19.3-Mbps DTV signal, says Sakata.
Broadcasters aren't content with current compression rates, he adds. They continually look for new ways to squeeze existing DTV channels into smaller streams. That creates more space in the signal for additional services.
Harmonic is also introducing Windows Media 9 and MPEG-4 compression capability on its flagship MV100 standard-definition encoder. An MPEG-4 product should be delivered to customers by late summer, says Sakata, and a WM 9 version by early next year. So far, initial interest in advanced compression platforms has come mainly from European telephone companies. But Sakata expects MPEG-4 and WM 9 to find their way into traditional broadcast applications, like ENG, once professional decoders hit the market. "You could move to a simple Windows Media platform to acquire an edit," he suggests.
Harris Broadcast will introduce Windows Media 9 and MPEG-4 capability on its NetVX encoding platform, with product expected in the fall. But that is just part of a broad extension of the NetVX product, says John DeLay, director of digital television products.
"From a high-level view of the NetVX platform, it serves as everything from a standalone encoder for ATSC broadcast applications to a sophisticated networking solution," says DeLay. "It will take in any type of service, map it internally through a cross-connect switch, then map it to any type of output."
At NAB, Harris will introduce video-over-IP capability for NetVX through a new Gigabit Ethernet interface that enables high-speed file transfers. "With rates up to 250 Mbps, we can simultaneously run 64 video-over-IP streams bidirectionally," says DeLay. Plus, the company will demonstrate next-generation statistical-multiplexing technology for the networked environment, along with the ability to change bit rates.
"We're working on an implementation for transport-stream splicing for ad insertion and logo insertion in the compressed domain," says DeLay, who see potential for the system in centralcasting applications.
In the traditional ATSC broadcasting, Harris has seen "an aggressive uptake of HD encoders in the last six months," says DeLay, noting that 60% of his encoding customers have purchased HDTV product. He estimates his company's share of the ATSC market at more than 50%.
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