The Digital Media Project (DMP) has released its second major spec. Interoperable DRM Platform 2, or IDP-2, was published last month after having been ratified at the DMP General Assembly in Torino, Italy in February. DMP is a DRM standards initiative led by Dr. Leonardo Chiariglione, the founder of MPEG.
With IDP-2, DMP has finally revealed details of its approach to DRM interoperability. It is a genuinely new approach that builds on the IDP-1 spec that DMP released a year ago, as well as other sources such as MPEG-21, the TV Anytime Forum, and the influential 2003 whitepaper Self Protecting Digital Content by Paul Kocher of Cryptography Research Inc.
DRM interoperability is a problem that has to be solved in order to enable consumer media services that provide decent user experiences and implement innovative business models while protecting intellectual property from misuse. Yet interoperability of a complex, network-related technology like DRM is antithetical to the fundamental ways in which such markets behave: if strong market leaders emerge, they tend to lock customers into their platforms and have little incentive to interoperate with vendors that are lower on the totem pole.
That said, there have been essentially two approaches to DRM interoperability thus far. One is to leave existing systems in place and attempt to build technology to interoperate among them. The other has been to create a flexible DRM standard and get device makers and content service providers to implement that standard.
Examples of the former approach include Coral and Secure Video Processor (SVP). Coral enables service providers to build services that offer DRM interoperability, while SVP does some of the same things for set-top-box-like devices instead of services. Both essentially follow market dynamics: they are technology that facilitates interoperability where there is a market demand for it. For SVP, the demand is mostly a future hypothetical one based on emerging home networking paradigms. For Coral, demand for interoperability could come from almost anywhere and potentially be supported. Both depend on some level of cooperation from vendors of existing technologies with which interoperability will take place.
There are two prominent examples of the latter approach to interoperability, the approach of "build it and they will come" DRMs for future devices: OMA DRM from the wireless telecoms industry, and more recently, Marlin from the "media player" consumer electronics industry. While Marlin is a brand new spec, OMA DRM support (for version 1, at least) is now built into hundreds of handset-type devices around the world and implemented in dozens of services.
WIth IDP-2, DMP envisions a third approach, almost a Hegelian synthesis of the previous two. IDP-2 starts with a set of notions of how content information is packaged in an XML-based file format that includes an identifier, metadata, rights information, and so on -- mostly based on MPEG-21 standards such as Digital Item Description Language (DIDL), Intellectual Property Management Protocol (IPMP), and Rights Expression Language (REL). Then it includes a small set of core DRM functions that are assumed to be present in every device that can exercise rights to content such as play and store.
The flexibility of IDP-2 comes via the ways in which devices' DRM functionality can be expanded. IDP-2 compatible devices can provide storage for "DRM Tools," which expand their functionality beyond the core. If a content license (which can be part of a content item or separate from it) comes to a device with rights that are beyond the device's capability to process, then the device can contact a registration agency to obtain the required DRM tools, provided they work with the device in question. DRM tools can also be bundled with content items -- this being an idea from Kocher's aforementioned white paper.
The success of IDP-2 will, of course, depend on device vendors and service providers deciding to implement the spec. But beyond that, any interoperability effort depends on content providers to approve mappings of rights (and redistribution of content) from one system to another. The DMP membership includes three device makers from the "media player" camp: Matsushita (Panasonic), JVC, and Mitsubishi. Matsushita is also a key player in Coral and Marlin (i.e., both of the aforementioned interoperability approaches).
In the typical course of events, service providers and device makers design services for consumers, and as part of that process, they obtain major content providers' blessings to use their content in those services.
IDP-2 also expands on IDP-1 in a few other interesting ways. IDP-1 focused only on portable devices that act as "slaves" to more powerful devices (e.g., PCs or set-top boxes) and only supported authentication of devices. IDP-2 now supports both portable and "stationary" devices; it also supports authentication of users, devices, and domains. In IDP-2's definition, domains can be groups of user and device identities, not just groups of device identities as in other schemes.
In addition, the documentation for IDP-2 includes a series of use cases that is far more comprehensive than those supplied with the IDP-1 spec, which tended towards "corner cases" more of interest to consumers and individual content creators than to mainstream media distributors. It also includes a very helpful walkthrough document that provides an overview of the IDP-2 spec.
DMP's work does get more interesting with each spec that the group releases. It has begun work on what will become IDP-3. We have been intrigued especially by DMP's initiative to codify what it calls Traditional Rights Usages (TRUs) and map them to rights in a DRM scheme -- which still has yet to be completed. DMP's specs are intended to cover both content that is protected (e.g., encrypted, or "governed" in DMP parlance) and content that is not -- i.e., content that has its rights described in metadata but is still in the clear, as is the case with the Creative Commons scheme.
Will DMP's series of specs inspire device makers, service providers, or content owners to implement services based on DMP's innovative concept of interoperable DRM, will they remain merely interesting curiosities, or will some of the ideas in those specs make it into others? Those continue to be the pending questions concerning the Digital Media Project.
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