Of course, delivering interoperable DRM in the marketplace is not just a matter of technology.

One obstacle is that consumers already have an appealing alternative to any DRM: unprotected content. With unprotected content, there is no need for agreements among providers about business model details and no need for a common interoperability technology. As consumer needs surface (for example, transferring videos from the web to portable players), technology can be created without constraints that fulfills that need. Such organic growth is not practical in a world of DRM-protected content, which means that technology suppliers must anticipate consumer desires and plan in advance to accommodate them.

Another obstacle is that for interoperability to make sense, business models must be, in some broad sense, compatible. If one DRM technology only supports a subscription business model, and another supports only supports a purchase business model, it is simply not meaningful for the two to interoperate.

The Coral Consortium is addressing this problem by promoting an industry consensus around broadly-compatible DRM business models and rules. Known as Ecosystem-A and described in another white paper, this home network interoperability model is intended as the basis for Coral's interoperable DRM brand. From a technical standpoint, the Coral technology supports multiple ecosystems, but in practice, in terms of providing a reasonable consumer experience, it is important to have a single ecosystem that encompasses an understandable and consistent set of DRM rules. Fortunately, the content industries seem to be converging on a common understanding of business rules, making it practical to establish a common ecosystem for DRM interoperability.

The common ecosystem is critical to allowing a sensible mapping of managed rights from different DRM technologies. If Coral can achieve broad industry convergence, then common rights (such as purchase, device transfer, subscriptions, etc.) can be mapped from disparate DRM technologies into the rights expressed by the Coral rights token, and made visible and understandable to the consumer. Although there will certainly be rights expressible in specific DRM systems and not others, those can also be expressed in Coral framework, simply with the proviso that they apply only to specific types of content -- and as that situation is the exception, not the norm, it should present no significant problems for consumers.

A third obstacle to interoperability is that it requires that software interfaces to specific DRM technologies be made available to developers. For DRMs like WMDRM that are explicitly designed for integration and delivered with a software development kit (SDK), this is not an issue, but for others, such as Apple's FairPlay, the software interfaces are closed, proprietary, and tightly controlled.

Interoperability can be achieved with the Coral approach only if the DRM has an SDK that exposes a full set of DRM functions, for both content and license generation as well as content use. A consume-only model (e.g., for integration with player devices) is not sufficient: the SDK must also provide full access for integration with content vending and distribution services.

Market Incentives

For the Coral interoperability technology to be a success, participants in all parts of the value chain have to see the benefits and use it.

For device manufacturers, it's not a big issue, because even devices that know nothing about Coral (e.g., "PlaysForSure" compliant devices that support WMDRM) can participate. Of course, some business rules (like subscriptions and expiration) require device capabilities that aren't present in all devices, but the mapping between Coral rights tokens and the individual licenses created for DRM systems can accommodate such restrictions. That accommodation comes at the cost of making DRM differences visible to the user, but in a way that is no worse than the restrictions that the device already had, and better than no interoperability at all.

For content providers, the primary impact is the encouragement -- but not requirement -- to adopt uniform schemes for identifying content, so that a right tokens can be unambiguously associated with different versions (and different DRM protections) for the same content.  Yet this is merely a larger version of content identification problems that content providers have had all along and that have been addressed by a number of different standard identification schemes.

The Coral technology's biggest impact is in the space of content fulfillment, where licenses are actually distributed (usually with the content itself). For these parties, adopting the technology means adding significant mechanism to their license creation and distribution, because they must create and distribute both the Coral rights tokens and the technology-specific DRM-licenses. This is all behind-the-scenes mechanism, but there is a lot of it -- and there are also complex business relationships (e.g., revenue-sharing for different distribution channels) that have to be established.

For consumers, simple business models using the Coral technology will be essentially indistinguishable from proprietary DRMs. However, once the Coral ecosystem is populated, many interesting scenarios become practical.

For example, a consumer might purchase a song while listening on a DRM-enabled cellphone. This means that the consumer obtains a rights token, as well as a DRM license that the cellphone uses (e.g., for the OMA DRM that protects the song). When the consumer comes home, the cellphone can talk by BlueTooth to a Coral gateway, which automatically obtains the appropriate technology-specific DRM license for the consumer's home entertainment system (which might support WMDRM), and can download and store the song there. The Coral gateway might become involved again to obtain a license for playing on a portable media player. This exciting scenario is possible only if all the DRMs can interoperate, and that is what the Coral technology promises.

Delivering the Solution

Can Coral deliver? In this case, delivery means both technology and business relationships, and as usual, the relationships are the hard part.

The WMDRM integration is a promising start, because it shows that a DRM not designed for Coral can work in the Coral world without any changes. It is more sophisticated and complete than the earlier proof-of-concept demonstration with OMA DRM. However, the WMDRM demonstration is purely technical and does not address the business issues of broader interoperability. Even the technology aspect is strongly dependent on Microsoft's current business model for WMDRM, which has its roots in Microsoft's mission as a software company.

Today, WMDRM, which is distributed as an SDK, is specifically targeted toward establishing a large community of interoperable devices and services (the PlaysForSure initiative). The SDK nature of WMDRM is what enables Coral to define an integration strategy. Even without Coral, interoperability among WMDRM devices and services is straightforward, since Microsoft supplies the technology and the rules. However, recent revelations about Microsoft's forthcoming Zune device suggest that it may be departing from that business model. Will Microsoft close parts of its SDK, or engineer a Zune-specific distribution channel that cannot interoperate with existing PlaysForSure devices? If so, then the Coral interoperability story for WMDRM is no longer as straightforward, since it would require active adoption by the Zune player and its associated distribution system to succeed.

Most other popular and nascent DRMs all seem to be taking the SDK route, at least for now, although they have proprietary and license restrictions that can be more strict than WMDRM. For example, it seems entirely plausible that Coral could do a WMDRM-like integration with the Open Media Alliance's OMA DRM, RealNetworks' HelixDRM, and certainly the forthcoming Marlin DRM, which is being developed by a core group of companies that are also active in Coral.

The elephant in the room, of course, is the FairPlay DRM used by Apple's iTunes service and iPod players. FairPlay is a completely proprietary vertical stack that is available only to Apple, and Apple has been zealous about guarding its rights to that stack. The recent experience in France, where Apple may have left the French market entirely rather than supporting legally-mandated interoperability for iTunes, suggests that Apple will not easily give up. Although the FairPlay file format has, on occasion, been sucessfully reverse-engineered to support compatibility with other services (e.g., by RealNetworks), that was not complete interoperability and it has not proved to be a sound long-term basis for reliable interoperability.

Another more diffuse obstacle is the proprietary nature of the content distribution systems in special-purpose markets such as cellular telephone networks and pay television. These typically closed systems are operated and controlled by single parties. Unlike audio and video content companies that are embracing diverse and general-purpose distribution models using the Internet, the relatively closed cellphone and video channels are still learning about the benefits and demerits of owning the whole stack, and are not as strongly interested in interoperability. This is particularly true in the video world, where pay television and controlled access systems are by far the dominant distribution model for rights-protected video.

The problem with interoperability in general, and DRM is no exception, is that the benefits accrue primarily to the small players, not the dominant ones. Thus, the dominant players (e.g., Apple, the pay television companies, and -- potentially -- Microsoft) may see little incentive to adopt a technology that would allow their customers to take their business elsewhere. For the smaller services and device manufacturers, the Coral picture may be much more appealing, but even widespread adoption by 15% of the market probably doesn't count as success. Although interoperability may be appealing to consumers, it is not clear that consumers can have sufficient pull through the rest of the value chain to foster adoption.

The Coral Consortium has developed effective technology for interoperability, and has elucidated the business issues that must be addressed for interoperability to happen. However, it is hard to see the technology becoming widespread unless Apple, in particular, decides that interoperability is desirable.

Olin Sibert is President of Oxford Systems, Inc., and a GiantSteps Media Technology Strategies Affiliated Consultant.

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