Since 1993, the DVB Project has provided a vital forum for manufacturers, network operators, broadcasters and service providers to agree on the way they will address new technologies in the pre-competitive phase. DVB has a wide membership across the globe and removed the word “European” from its name five years ago.
By its own count, since 1993, DVB has completed two discrete phases of work and is beginning a third in 2005, which it terms DVB 3.0.
Although, with trademark irony, DVB likes to name its work phases after revisions of software, DVB still has its organic origins in broadcast, a very different world from the others it is encountering through convergence.
The vision for DVB over the next phase of its development is to be an enabling forum for pre-competitive standards-setting in the “connected world” of networked digital media and applications.
Evolving in logical steps
In its first phase, DVB focused on specifying the physical layers for MPEG delivery, network independent protocols, professional interfaces and “data-container” solutions for satellite, terrestrial and cable (DVB-S, DVB-T, DVB-C) services. One example is the DVB Data Broadcasting standard.
In 1998, DVB made a grand entry to the software world with its work on the Multimedia Home Platform (MHP) software stack for interactive TV. Also completed was the Internet Protocol infrastructure, advanced codecs and content protection (copy protection and content management) software.
As DVB's expanding focus starts to overlap with digital media standardization processes elsewhere, DVB has begun actively harmonizing its output with other groups beyond the broadcast world.
Today, DVB's work includes integrating advanced codecs, the new satellite standard DVB-S2, Internet Protocol issues, the MHP, copy protection technologies and DVB-H. Finally, DVB is still active in expanding the standard into the Far East and Latin America.
Advanced codec support: AVC/H.264
DVB's mission has always been to deliver MPEG transparently to the home. Because the MPEG-2 standard is frozen, implementations of MPEG-2 encoders have just about reached the theoretical efficiency limit of the technology. The MPEG-2 standard can now provide the same initial quality at about one-sixth of the initial reference bit rate.
Although MPEG-2 is being used over IP in some video over DSL services, it is hamstrung by high audio overhead and limits on what encapsulation and synchronizations are possible. MPEG-2 was not designed to work at low bit rates and in interactive multimedia environments.
The next generation of set-top boxes with broadband connectivity or PVR functionality provides an excellent opportunity to implement a whole new variety of advanced codecs. That could include proprietary, open-source and Java-based codecs. Standards might encompass H.264/MPEG-4 AVC (Advanced Video Coding), MPEG-4 AAC (Advanced Audio Coding) and the Microsoft-originated SMPTE VC-1.
The DVB Audio and Video Coding Group examined audio and video codecs available for integration with existing DVB work and has recommended H.264/MPEG-4 AVC and AAC. This announcement followed intense discussions regarding licensing terms for broadcasters.
DVB-S2: Upgraded satellite system
DVB-S2 is an entirely new satellite delivery standard that is more efficient and scalable than its predecessor, DVB-S. Commercial requirements came from some of the largest satellite users, needing to use transponder channels limited to 26Mb/s. DVB-S2 uses Amplitude and Phase Shift Keyed Modulation (APSK) with a different forward error correction system and low-density parity check. Combined with a sharper roll-off within transponder, the result is a band-efficient, reduced co-channel interference platform. Finally, all this has been achieved in a new chip design that matches the same physical size as a DVB-S chip.
DVB and the Internet Protocol
Since 1999, DVB has been working on the problems and opportunities of IP networks delivering TV. This is obviously an area where the work of DVB might duplicate or overlap work done elsewhere, and DVB has increased its liaisons with outside organizations. Besides the ISO, ITU, IETF and the W3C, where work is already under way on these issues, DVB has had extensive contact with the DSL forum, the Digital Living Network Alliance (DLNA) and others.
Multimedia home opportunity
Since its completion in 1999, the 1000-page DVB MHP standard has enjoyed a slow and steady adoption curve. Most promising have been the adoptions of the standard in the USA by Cable Labs of the Open Cable Applications Platform (OCAP), and by ATSC of the U.S. terrestrial equivalent, ACAP. MHP also has a Japanese home in the form of the Association of Radio Industry Businesses (ARIB) “execution engine.”
Unfortunately, after an early start, European MHP implementations now appear to have slowed. Although manufacturer and broadcaster support is strong, retailers and consumers are hesitating to adopt the technology. According to the MHP Web site, consumers are waiting for PVRs and broadband-IP enabled set-top boxes to become available with MHP features.
MHP progress report
Even so, MHP continues to enjoy some expansion. In Italy, 1.5 million digital terrestrial MHPs are installed, thanks primarily to government subsidized boxes. In Korea, SkyLife has installed 1 million satellite MHPs. Leading cable operator CJ CableNet launched MHP services in January 2005.
In Germany, ARD, ZDF, RTL and ProSieben/Sat1 have MHP services on-air, to a small installed base. This represents a trial service, but early results are encouraging.
In Finland, there are approximately 30,000 MHP-equipped devices. YLE is broadcasting MHP services via satellite.
In Spain, Catalan public broadcaster TV3 operates an MHP service.
Trials of MHP services are ongoing or planned in Australia, Austria, Belgium, Czech Republic, Denmark, Hungary, Malta, Norway and Sweden.
DVB in your hand
The DVB-H (handheld) standard is a time-sliced variant of DVB-T, but it's optimized for chip power, battery consumption and the screen refresh rates of handheld devices. There is great interest from both broadcasters and mobile network operators.
Broadcasters are eager to expand their reach, and mobile service providers are looking for new services to provide — and charge for. Crown Castle in the USA and several German public broadcasters have already begun trials. DVB is looking ahead to the various 3G and 4G networking technologies at present, including WiMAX and the more exotic IEEE 802.xx's. This could be one of the more exciting things to watch on the DVB front in coming months.
Copy protection and content management
Finally, everyone is concerned about content protection. Here, DVB is addressing the importance of protecting content and holders' rights after it's been transmitted. When DVB began copy protection activities, it investigated and cataloged a vast array of proprietary and standardized systems. Using this data as a starting point, DVB then derived a reference model that enabled these systems to coexist on the platform
More recently, DVB has been envisaging usage scenarios and mapping traditional usage rights to various copy control states, complementing the work done by the Digital Media Project (DMP). DVB has developed a suite of documents, including a functional specification, a reference model and a system of authorized domains — an evolving set of solutions.
Overall, the DVB Project is a model for open, industry-wide and industry-led development of standards. DVB remains firmly linked to its origins in the broadcasting world. However, its work today is more liaison-intensive with other relevant specification drafting processes than ever before.
If you are interested in contributing or accessing DVB work, or assisting liaison between your favorite “next-generation” technology consortium and DVB, visit the Project's Web site at www.dvb.org.
Martin Jacklin is a technology writer and principal consultant at Broadcast Projects (www.broadcastprojects.com).
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