The Digital TV Group, the industry association for digital television in the United Kingdom, has published the latest edition of its D-Book specification for digital terrestrial television and hybrid broadcast and broadband products and services. While the announcement specifically mentions HbbTV, curiously no reference is made to the YouView consortium of British broadcasters and broadband service providers.

The seventh edition of the D-Book has been formally approved by the DTG. Version 1 of part B of the specification, for Connected TV products and services, has now been published to DTG members.

The DTG says it is the product of “two years of intense collaboration, resulting in a specification that maximises the use of international standards while maintaining proven interoperability with UK broadcast systems”.

The association says it has “worked closely with its members to meet the requirements of the BBC’s HTML applications, including the latest version of the BBC iPlayer, and other broadcasters’ catch-up TV players”. Furthermore, it says “to ensure international harmonisation of standards the DTG is in liaison with HbbTV, ETSI, the Open IPTV Forum (OIPF) and DECE (Ultraviolet).”

D-Book 7 references the HbbTV specification. It includes several additional features, including provision for co-existence with MHEG, the current red button broadcast standard for digital terrestrial television in the United Kingdom. It also includes support for MPEG-DASH for adaptive streaming and common encryption handling for copyright protected content. These additions have been submitted back to HbbTV for consideration in version 2 of their standard.

Significantly, no mention is made of YouView, the consortium backed by the BBC, ITV, Channel Four, Five, BT, TalkTalk and Arqiva, which aims to launch its proposed hybrid broadcast and broadband platform in early 2012.

YouView published its core technical specification in April, which references D-Book 7 Part A as the baseline for the platform. YouView has said it will reference relevant sections of Part B once published by the DTG. YouView plans for require support for Adobe Flash for its user interface, although it will maintain support for MHEG for compatibility with existing broadcast interactive services.

Despite its comprehensive appearance, the YouView specification is remarkably ambiguous about the presentation technologies it will support or require. It refers to an Application Player as a “Runtime environment for the execution of Applications” and says examples “could be Flash player, MHEG engine, W3C browser”. The layered architecture could potentially support all three. There is little detail in the YouView specification that could actually enable a third-party developer to create a compatible application.

The DTG specification is only available to member organisations, which includes broadcasters and consumer electronics companies, as well as YouView and all its constituent shareholding companies.

The HbbTV specification, which has been embraced by broadcasters in France and Germany, is a published ETSI standard and is freely available as TS 102 796. However by design it favours platform or channel related applications, with limited opportunities for arbitrary third-party applications.

Meanwhile, consumer electronics companies like Samsung openly publish their platform specifications for Smart TV applications. Google TV will be based on openly available standards such as Android. Apple TV, if and when it supports third-party applications, is likely to be based on the same iOS architecture as the Apple iPhone and iPad.

Despite the promise of interoperable standards, the market for connected television applications in the United Kingdom is likely to remain confused and fragmented.