YouView has published its final Core Technical Specification. The document runs to over 200 pages and provides necessary but not sufficient specifications to build a box for the planned hybrid broadcast and broadband television platform. It does not yet address the middleware, programming interfaces or user experience that will enable it to do anything useful. Developers are left wanting more detail. As such, the publication of the specification is long overdue but shows how much more work is yet to be done.

The introduction states that YouView is “committed to helping develop common technical standards for connected TV.” It continues: “By publishing this YouView Core Technical Specification we are giving industry visibility of the technologies within a YouView device, thereby promoting further the commonality across connected TV implementations.” It concedes that “this specification in isolation does not enable a manufacturer to build a YouView branded device.”

The YouView core technical specification references the DTG D-Book 7, which is only available to members of the Digital Television Group. It currently refers to Part A, which covers the broadcast specification for the United Kingdom and will reference Part B, which covers broadband internet protocol delivery, once this has been finalized.

The hardware requirements are stated for a twin-tuner, high-definition, digital terrestrial television digital video recorder. It requires at least 512 megabytes of random access memory, an internal hard disk with at least 320 gigabytes of storage, an Ethernet network port, two USB 2.0 device ports, a 1280×720 32-bit graphics plane, and support for MPEG-2 and MPEG-4 video and 5.1 channel surround sound. It specifies a minimum set of remote control functions, but not a standard design. The operating system is specified as embedded Linux.

The document is deliberately equivocal when it comes to certain aspects. With respect to the processor it simply states that all consumer devices will need to be based on system on chip processors “for which the ability to support the necessary functionality has been established”. Unlike the previously released draft documentation, no specific vendors are mentioned. With regard to the application execution environment it simply gives examples of an Adobe Flash player, MHEG engine, or W3C web browser. It covers integration of MHEG-5, but is completely silent with respect to Flash or web standards.

While in some respects the specification is highly prescriptive, and rightly so in regard to some aspects that might otherwise be left to discretion, it is nowhere near comprehensive enough to ensure compatibility or interoperability between implementations from different manufacturers. That may be left in part to the DTG D-Book specification and more importantly test suites intended to ensure conformance.

As far as it goes, the YouView Core Technical Specification describes a particular profile of device based on existing industry standards. It is very much bottom up in approach, starting with the hardware and the operating system, without addressing the actual application environment. It might allow manufacturers to start designing motherboards, but it is of little help to application developers.

The approach adopted by YouView is rather different from that of previous interactive television standards initiatives, which have attempted to define the application middleware and presentation environment, often without reference to the hardware.

It also differs from other connected television environments, which tend to be specified through a software development kit or application programming interface which defines exactly what developers can do and how this must be implemented. So, for example, a developer can create an application for a Samsung television without knowing or caring about the underlying hardware environment.

YouView says that publication of a developer application programming interface will follow. That is what will specifically define the YouView platform and where most of the work will be required.

YouView has announced further device partners Huawei, Pace, Vestel and a consortium called Manhattan Technology. These will join Cisco, Humax and Technicolor, which have already committed to developing YouView set-top boxes.

So far YouView is limited to standalone digital video recorders and none of the major consumer electronics manufacturers that produce the vast majority of digital televisions, like Samsung, LG, Sony, Panasonic, Philips, Toshiba or Sharp, have yet to announce any support for the platform.

It is difficult to see how YouView can claim to “change the way you watch TV forever” if it does not address the connected television market, which is by and large defined by global manufacturers.

However, the initial YouView specification, based as it is on the DTG D-Book 7, provides sufficient detail on aspects such as its use of progressive download and adaptive bitrate delivery, media compression schemes and container formats, subtitle formats, encryption and digital rights management to enable communality and potentially interoperability to be achieved across other platforms where appropriate.

That said, the YouView specification gives only cursory mention to multicast distribution, arguably a fundamental technology for a true internet protocol television service. While support is required, multicast is dismissed in a few paragraphs, by reference to IGMPv3. In this respect, the YouView specification is significantly less helpful than the work of the Open IPTV Forum.

As such, YouView seems to be more focused on delivering catch-up television services like BBC iPlayer than in implementing a true hybrid broadcast and broadband platform.

While the publication of the YouView Core Technical Specification must be welcomed as long overdue, it serves to demonstrate how much more work has yet to be done, particularly in achieving interoperability between implementations from multiple manufacturers and enabling a rich range of applications and services.