We have more audiovisual choices than ever, live and on demand, free or paid, on so many different devices and displays. Yet it still seems hard to know what you can watch where, and how to find it.

This white paper discusses the background to the Service List Registry, the problems that it solves and the benefits that it provides to the audiovisual ecosystem and end users.

Broadcast signals

Conventional digital cable, satellite, or terrestrial television receivers can scan for signals over a range of frequencies and decode service information metadata that identifies and describes the streams of data that they carry. This service information is embedded in the transmission, so it can be licensed and regulated in the same way. The system is also reasonably secure, as the complexity of the transmission system makes it difficult to tamper with. Only a limited number of broadcast engineers really understand it. They are reluctant to change it too often, so it remains relatively stable. It uses widely accepted industry standards, so that any compatible receiver can decode the data and present it to the user in an appropriate manner.

This conventional approach has worked well, but it is limited to specific platforms and begins to break down as more viewing moves online. What if a device does not have a traditional tuner, or the user does not have access to a cable, satellite, or terrestrial connection? What about hybrid services that may be delivered over different networks, including fixed and mobile internet connections, which are becoming ubiquitous?

Online discovery

Until now there has been no universal service discovery mechanism for online audiovisual distribution. This has generally relied upon proprietary apps or devices bound to specific services. The general approach has been driven by searching and browsing, assuming users know what they are looking for and will recognize it when they see it. Users have limited ability to customize the presentation or discover new services. That might suit some service providers, who may prefer to keep people within their own walled gardens, however it is not always convenient for users.

Not only do individual apps present usability problems, but they also raise issues of accessibility, prominence, provenance, and competition. They can also create problems for users if they are unable to rely on the authenticity of a service or the consumer protections that are generally accorded to licensed services. These are all key concerns for regulators, who have historically provided governance through spectrum and service licensing. Certain types of programming are viewed as a public service, to which there should be universal access within a given territory, subject to any applicable licensing regime. Yet it can be surprisingly difficult to access some of these services on different devices, despite their popularity.


The problem is that no single service provider or platform, however powerful or dominant they become, is likely to meet the needs of all users. The success of any single service has historically been as part of an aggregated experience that addresses many different need states. In the same way that no publisher could provide all the books someone might wish to read, no single studio or service provider is likely to cater for all their audiovisual requirements. The web has become phenomenally powerful because it offers open access to any number of participants, rather than restricting people to portals or gateways.

Historically, many broadcasters have had national prominence, supported by regulation. Consequently, some national broadcasters have formed platforms that have become highly recognized brands. This has enabled them to determine to an extent how their services are delivered on receiving devices. However, with thousands of channels available worldwide, even national services may have less influence in a global market. In a world of apps, powerful global players may be only a click away.

While global technology corporations may aspire to establish their own search or aggregation platforms, media service providers are reluctant to hand them the keys to their castles.

Service directory

The solution is a system that allows any app or device to query an open online directory of authorized audiovisual services, globally, nationally, or regionally. The federated structure means that no one authority controls a central service list, which would be politically and commercially contentious, and anti-competitive. Instead, registry participants receive delegated authority for relevant sets of services, at a global, national, or regional level, by service offering or individual provider. This means that the system can scale indefinitely.

As the registry is based entirely on open standards, there is no risk of proprietary lock in. In theory, anyone could operate a similar registry system. In practice, it is more convenient for devices and applications to query a single well-known top-level registry, a list of lists, that can refer them to other reliable sources. This requires trust, which partly relies on technical security and availability, but also on the credibility and integrity of the system.

In many respects, the registry is like the domain name system that is the fundamental foundation of the internet and web technologies. Most regulators already maintain lists of licensed services within their jurisdiction. The Service List Registry simply allows authorized users to associate their services with the relevant technical parameters, branding, and descriptions to enable them to promote them to users. Mechanisms will be available to ensure that appropriate prominence is provided for public services where this is required nationally or regionally.


It is important to recognize that while some services may be available globally, some services may be restricted nationally or regionally, for various reasons related to rights and commercial arrangements. The registry includes powerful means of advertising the geographic availability of specific services within defined regions. It does not intrinsically impose geographic or other restrictions on availability, which can be determined by individual service providers according to their requirements.


Services may also be made available according to a time or date schedule, either by time of day or on an occasional basis. The registry allows for services to be promoted by temporal availability and for this to be scheduled in advance. This can support anything from regional opt-in services during the day to temporary pop-up services for special events. Other than advertising when such services are available, the registry does not dictate how such capabilities are delivered.


The Service List Registry makes it possible to combine services across multiple platforms and delivery systems. That can extend to switching seamlessly between national broadcasts and regional streams. Significantly, it can allow existing broadcasters to provide hybrid services that embrace broadband distribution over fixed and mobile networks, while continuing to support legacy channels. This is a key enabler for a long-term transition to next generation online platforms.


For device and display manufacturers, the registry offers comparable capabilities to the embedded service information that has conventionally been provided by cable, satellite, or terrestrial transmissions. It does not dictate how this information is presented and it allows them to continue to innovate and differentiate their products around the user experience. An interoperable open standard offers economies of scale across global markets, in a world where margins on product are minimal and unable to support the integration and testing of multiple proprietary systems.

While some manufacturers have started to offer their own service lists, the availability of an open de facto industry standard system offers many benefits. Not least, it avoids the administrative overhead of managing many thousands of relationships worldwide and taking on the relevant legal and regulatory responsibilities, while ensuring that the technical information is accurate and updated. Furthermore, it does not preclude vendors from using the registry to populate their own branded lists of services and arranging them as they wish to meet their own commercial requirements.

Consumer electronics companies are likely to be key drivers of adoption, selling hundreds of millions of devices a year. Integration of service list registry requests will be facilitated by published protocols, provided application programming interfaces, and software development kits with test cases. Vendors are also free to develop their own integrations, confident that they can rely on version controlled open standard interfaces to ensure interoperability. This will be promoted through licensing Simple Service Selection as a product feature.


The Service List Registry public query interface will always be entirely free and open to end user devices and applications, with no charge or limitation on usage. Service providers will pay a nominal fee for inclusion of their services in the registry, based on their scale and volume. In some cases, this may be through existing licensing arrangements with regulators. The fees will be such that cost is unlikely to be a barrier to adoption. Early adopters will be able to trial the service free of charge for a limited period. Service providers are naturally motivated to ensure that their services are appropriately promoted, and the Service List Registry will be an integral part of this.


For end users, the registry will be virtually invisible in its operation, working behind the scenes to offer available services that are compatible with their device or display. They will see the benefits of Simple Service Selection in greater choice, convenience, and control of their audiovisual experiences. This may manifest itself in different ways, as service providers, application developers, and device manufacturers will all be able to innovate the user experience in a competitive market.


The Service List Registry offers an elegantly simple solution to a complex problem. It is easy to implement and supports legacy services as well as new forms of online audiovisual delivery. The future of audiovisual discovery is here today.