The Service List Registry is the exclusive provider of global registry and resolution services to enable the discovery of HbbTV applications.
The HbbTV specification for Hybrid broadcast broadband TV enables the signalling of applications associated with broadcast channels through a broadcast Application Information Table or AIT.
When the source is not provided over a traditional broadcast signal or connection the information required to link to an application may be unavailable.
The necessary signalling may not be delivered over a distribution network.
The display may be connected to audio and video decoded by an external device.
The audio and video may be provided by an online source.
Additional mechanisms have been introduced to enable Application Discovery over Broadband or ADB, based on either available service information associated with the channel or invisible watermarks embedded in the media.
Service Information — DVB Service Information can provide a unique reference to a broadcast service where AIT signalling is not present.
A combination of country code, service name, and original network identifier are used to derive a unique domain name for the service.
ADB Phase 1 was published in September 2016 as ETSI Technical Specification TS 103 464 V1.1.1.
Watermarks — ATSC 3 audio and video watermarks can alternatively be used to encode a unique reference directly in the media.
A server code is encoded in the invisible watermark and is used to derive a unique domain name for the service.
ADB Phase 2 was published in May 2020 as ETSI Technical Specification TS 103 464 V1.2.1.
The unique domain name derived from the service information or watermarks can be resolved to an authoritative fully qualified domain name by reference to the registry operated by the Service List Registry.
The client can then request an AIT file in XML format from the authoritative domain. The AIT file provides a reference to the relevant HbbTV application.
This system of application discovery extends the delivery of interactive services and dynamic advertising beyond broadcast networks. It uses an international industry standard approach that can work across the various operating systems of multiple consumer electronics manufacturers.