WHILE TELCOS’ AND OTHER ENTITIES’ demands for a standardized advanced compression solution recently have generated significant momentum for MPEG-4 Part 10, backers of the competing VC-1 compression standard are confident their platform will have a major role to play in telco TV deployments.
As xchange went to press in February, VC-1 — which is based on Microsoft Corp.’s Windows Media 9 technology — was up for balloting in the final committee draft stage within the Society of Motion Picture and Television Engineers (SMPTE). That’s still a long way from a final standard, but can serve to provide chip developers some degree of certainty that ongoing changes will not require wholesale restructuring of their processors. “The final committee draft ballot is the step that asks the question, ‘Is the document technically stable?’” says Michael Dolan, president of Television Broadcast Technology (TBT) Inc., who is chairman of SMPTE’s VC-1 ad hoc group. “The outcome of the ballot, closing in two weeks (end of February), will provide some better indication of the status.”
There’s always the possibility there could be surprises that could delay progress, acknowledges Jordi Ribas, director of technical strategy in Microsoft’s Windows Digital Media Group. “We won’t know until the fat lady sings,” he says. “This is a quality-driven process that will go on as long as necessary to achieve the necessary improvements.”
But Ribas adds that while things were “a bit rocky” at the beginning of the SMPTE process last year, a spirit of cooperation has prevailed in recent months with a high level of approval within the working committees on various aspects of the draft. “To be honest, participating in something like this was a learning process for us [at Microsoft],” Ribas says. “We had never done a big standardization effort through SMPTE. But as time went by, we and others stepped up to the plate, and we have been working well together.”
While the state of development in the standardization process would appear to put VC-1 well behind the competing MPEG-4 Part 10 standard, which officially was sanctioned by the International Standards Organization last summer, there are major differences between the two processes and what can be expected of the pace of commercialization. Unlike H.264 (the Part 10 compression standard), there aren’t a lot of contributors to the VC-1 platform fighting over which concepts get incorporated because, from the beginning, a stated goal of the standard was that it be backward-compatible with existing commercial implementations of the precursor Windows Media 9 compression system.
“There’s been a little bit of confusion where some people have thought compatibility might be broken,” Ribas says. “The goal here is to create documentation of how the specs work so that people can build products independently while ensuring compatibility with WM9. VC-1 is about documenting products that are already in the market.
“There are still a lot of disputes over interpretations of specs to be resolved with H.264,” Ribas adds. “You can have a number in the MPEG-4 spec that people might interpret ten different ways. In our case, we know what the true interpretation will be.”
Indeed, interoperability is a much harder thing to achieve among disparate manufacturers of encoders and decoders in the H.264 space than it is with VC-1, notes Lisa Hobbs, director of marketing at encoding supplier TANDBERG Television. “MPEG-4 is a huge tool box,” she notes. “Even with everyone using the main profile [of Part 10], there are a tremendous number of tools to choose from.”
This means encoder and set-top box suppliers must work together to make sure their systems interoperate, which usually happens when service providers make specific choices as to which suppliers they’re going to use. “IPTV is a closed system, so you don’t have to wait for some final certification of interoperability among all players to create an interoperable end-to-end system,” notes Michael Hawkey, director of the satellite business unit at STMicroelectronics, a supplier of set-top chips. However, he adds, it will be a long time before things reach the state of ad hoc interoperability that prevails today with MPEG-2.
“A tremendous amount of testing has to go on where MPEG-4 is concerned,” Hobbs says. “But interoperability isn’t as pronounced an issue with VC-1. If there is a question of what the VC-1 standard means, there’s really only one source to go to for an interpretation, which is Microsoft. But the interoperability issue isn’t completely negated, because you have to be compatible across SDTV and HDTV bit streams. We’re doing work with VC-1 set-top manufacturers testing both bit streams.”
Also working in VC-1’s favor is the fact that so many telcos, including BellSouth Corp., SBC Communications Inc. and Verizon Communications Inc., have made commitments to use Microsoft’s IPTV platform. While H.264 can be deployed over the Microsoft IPTV platform, efficiencies tied to incorporating all the benefits of an integrated Microsoft solution appear to favor use of VC-1.
“There’s an entire ecosystem my group is working on which the decoding device has to tie into, including DRM (digital rights management) and other security components,” Ribas says. “We’ve done a huge job to integrate all these functions.”
As a result, he adds, more than 50 manufacturers’ set-tops and other devices have been certified through Microsoft’s “Plays-for-Sure” program, with another 100 or so slated for certification over the next year or so. “This is an assurance to telcos that when they use our platform, their customers can download a movie as easily to a portable media player as they can to the set-top, without requiring the telco to engage in a whole round of interoperability testing to determine whether the devices are compatible,” Ribas says. “H.264 would not be interoperable in this way.”
But there is one outstanding issue that could impede efforts of VC-1 supporters to catch up with the momentum surrounding MPEG-4 Part 10. So far as is known publicly, 12 entities within MPEG LA LLC, a consortium that administers joint licensing terms for patent holders that have intellectual property stakes in various standards, have registered claims to various pieces of the VC-1 standard.
Microsoft, as a member of MPEG LA, is working with these companies, which have not been named, in an effort to derive a royalty payments plan that is “competitive” with the one established for MPEG-4 Part 10, Ribas says. “We’ve done a good faith effort to work with these companies to make sure there is nondiscriminatory pricing respecting use of property rights,” he says. “At this point we can’t say what the price points will be.”
Until these issues are resolved, no one will know really what it costs to deploy a VC-1-based system. “Royalty issues are catching some providers off guard,” Hobbs says. “The hope in the industry is that the licensing will be no more onerous than it is with MPEG-4.”
| Links |
| BellSouth Corp. www.bellsouth.com Microsoft Corp. www.microsoft.com SBC Communications Inc. www.sbc.com Society of Motion Picture and Television Engineers (SMPTE) www.smpte.org STMicroelectronics www.st.com TANDBERG Television www.tandbergtv.com Television Broadcast Technology (TBT) Inc. www.tbt.com Verizon Communications Inc. www.verizon.com |
