Project Canvas, which plans to create a new platform for connected television in the United Kingdom, has finally published the draft technical requirements that it has previously refused to release beyond a closed industry group. The documents so far fall short of specifying the more contentious elements and it could be some time before it is clear how open the proposed platform will actually be. The proposed joint venture is meanwhile the subject of a further complaint to the communications regulator Ofcom.

Following considerable pressure to release the draft documents, having rejected a formal freedom of information request from informitv, the work in progress requirements specifications have been published on the project web site, although not it seems on the BBC web site as required by the BBC Trust. Nevertheless, the documents can now receive the wider scrutiny they deserve.

The core technical specifications for Project Canvas are all marked as copyright of the British Broadcasting Corporation and state that the BBC may freely reproduce and licence any feedback submitted in response. From this it is clear that the BBC is taking the lead in technical specification among the joint venture partners: ITV, Channel Four, Five, BT, TalkTalk and Arqiva.

The documents have previously been circulated to members of the Digital TV Group, the industry association which is developing its own specification for Connected Television. It is said the aim is to establish standardised building blocks that are due to be published in the DTG D-Book 7 specification later this year, which the Project Canvas platform proposes to reference.

So far, Project Canvas has published 14 sets of technical requirements, covering the platform specification and software architecture, broadcast and online delivery and protection of media, metadata, presentation engines, user interface and usage measurement.

Many of the documents date back to May 2010, but the first draft of the key specification for the consumer device, which draws together the various requirements, is dated 1 September, after the closing date for expressions of interest from device manufacturers.

The draft requirements specifications are reasonably extensive and relatively ambitious but lack rigor in many respects, compared to generally published broadcast or internet standards. The significant scale of the task they face will be apparent to those with experience in developing open standards and must be evident to those involved in working on the documentation.

The base specification is for a broadband network connected twin-tuner high-definition digital video recorder with a 300GB or larger hard disk. It is specified that the device must run the Linux operating system.

Support is required for MHEG-5, the presentation language currently used for Freeview and Freesat in the United Kingdom, and some similar services in other countries. In addition, devices are required to support a profile of W3C web technologies. These may include a subset of HTML-5 and CSS-3, and JavaScript 1.5 or later, with support for AJAX. More controversial may be support for Adobe Flash 10, although it is noted that consideration of this is ongoing.

Support for media delivery over an internet protocol network includes HTTP download, progressive download and adaptive bit-rate streaming, multicast, and what are termed presentation-engine specific delivery protocols.

An infrared remote control with over 40 specific buttons is required, including Red, Green, Yellow and Blue colour keys. A full alphanumeric keyboard may be optionally supported.

The specifications describe a usage collection agent to collate viewing figures for the platform provider, although it is suggested that users may be able to opt out of the collection of this data. Also among the requirements is the ability to connect an audience monitoring unit provided by the industry research company BARB. The usage measurement systems are only loosely defined at present.

A system of remote diagnostics is also envisaged, although it is noted that it may be necessary for the viewer to give consent for this to be used and may have the ability to disable this function.

While some of the technical requirements are quite detailed, many of the key policy issues, that will define how open the platform will be, are still not clear from the specifications.

Further documents, including the user interface style guide and interaction principles, user interface policy and trade mark licence policy, are due to be published in October, with the electronic programme guide policy to follow in December. These are likely to come under greater scrutiny by interested parties that may be less interested in the technical implementation and more concerned by the business implications.

A developer application programming interface and associated guidelines are not due to be published until February 2011.

Approval to participate in the proposed platform was given to the BBC on condition that the core technical specification, of which the developer API is surely a key component, be published on the BBC web site at least eight months before the first set-top boxes are marketed. That could put any launch back to at least September 2011, in time for the Christmas season, some two years behind the original schedule.

In reality, actually implementing and testing the specifications could take at least that long, even if some parties may have a head start. The draft requirements currently do not constitute a specification that a manufacturer could actually build, code and test against, although they might be able to outline an architecture and calculate a bill of materials. Implementing a prototype is one thing, but ensuring interoperability with a supposedly open standard is another.

So far, it is reported that some forty organisations have expressed interest in developing compatible products. The project team will evaluate these responses and select those with which it will partner.

Richard Halton, director of Project Canvas described the industry response as “phenomenal” and “a great endorsement of our open approach to working with industry partners”.

Speaking at the Media Festival Arts in London, for which informitv is a media partner, Mark Thompson, the director general of the BBC, said Canvas was not an “imperial gesture” from the BBC but an equal partnership in which anyone could join. He said has was “determined that we at the BBC ensure it’s not just for the big players.”

Kip Meek, recently appointed chairman of the proposed joint venture, said that while he wanted to ensure that each shareholder receives a proper and fair return for its investment, the openness of the service should not be compromised.

Earlier, Jeremy Hunt, the government minister for culture, media and sport said he was very positive about Canvas. “In terms of what I understand, I think it’s incredibly exciting. It will finally — for many, many people — remove the barriers between lean-forward and lean-back technology,” he said. “The chaos of the internet — for better or worse — will arrive in our living rooms.”

At the IBC trade convention in Amsterdam, Sir Michael Lyons, the chairman of the BBC Trust, said: “We approved Canvas on condition that the new platform is as open as possible. Open to other partners, open to content providers and manufacturers, and above all, open and accessible for consumers. Our goal is to stimulate competition and promote the next phase of growth in the industry”

It seems not everyone shares that view. The communications regulator Ofcom has received a further complaint about Project Canvas, at least the fourth so far. The latest complaint comes from United for Local Television, an industry association lobbying for local television services, the like of which the culture secretary may be keen to promote.

The group expressed its concern about the “challenging and arbitrary technical specification” which “risks seriously damaging the development of small-scale TV services” and could “prevent viewers from obtaining any streamed services on the open internet from TV channels who are unwilling or unable to meet the access terms”.

It follows a complaint from Six TV, which holds a number of restricted television service licences and is associated with ULTV. Other complaints have been received from Virgin Media and IP Vision.