BT Vision, the long-awaited video service from the UK telecommunications company, will soft launch to a limited number of existing broadband subscribers next month, with a full marketing push and its complete programming line-up now not expected until next spring.

BT is denying that it amounts to a delay in the launch, which it has always promised to deliver before the end of the year. The service is currently being used by a limited number of BT employees prior to being seen by the public. The company is adopting a cautious approach with what it describes as a “sensible” rollout to avoid disappointing customers and initially it will not have “all the bells and whistles”.

Speaking at the Streaming Media Europe conference in London, Richard Griffiths, technology strategy director for BT Retail TV Services, gave a few insights into the broadband video plans, while stressing the difficulties of delivering video over the existing BT network.

As a result of the structural separation of the national telecommunications company into separate wholesale and retail divisions, the consumer arm is required by regulation to acquire services from its parent on equivalent terms to other broadband resellers.

The BT network was simply not designed to deliver video, and does not support multicasting, making it uneconomic to distribute live television channels.

For this reason, the BT Vision service will combine broadcast programming delivered over the air through digital terrestrial television in conjunction with broadband video-on-demand services.

Essentially, it will provide an easy-to-use dual-tuner personal video recorder for Freeview channels, with a network connection that links to a home hub broadband gateway device.

BT Wholesale has developed an application driven quality of service mechanism, ADQ, which will be productised as ‘Advanced Services’ allowing the creation of a temporary fixed bandwidth pipe over a broadband connection.

BT Vision is planning to use a 1.5Mbps data stream to deliver video-on-demand services, significantly less then some other providers, even using MPEG-4 H.264 compression, to ensure that it can provide the widest coverage over its existing broadband network. It remains to be seen how the quality of the video will compare to current broadcast services.

Richard Griffiths revealed that BT Vision will use its own content delivery network, with nodes sited at ten locations around the UK, with 3 or 4 in London. “We’ve done the business and mathematical modelling,” he said. “We are very confident that our scaling and provisioning will be able to meet the anticipated demand.”

BT is planning to invest billions in a next-generation network known as 21CN, based on internet protocols, which will support multicasting. “Maybe we’ll look at multicast channels with 2CN,” said Richard, suggesting that live television could be carried over the network in the future.

BT first acknowledged plans for a broadband video service in July 2004, but its ambitions in this area go back considerably further. As date for the full launch of the BT Vision service slips into next year, the broadband access market is becoming increasingly competitive.

BSkyB, with its acquisition of Easynet, is building out its own unbundled broadband network. Tiscali has acquired Video Networks, provider of the London-based HomeChoice service with a view to a possible national roll-out. These and other operators are all potentially able to compete directly with BT Vision.

Meanwhile, British broadcasters are preparing their own broadband video services. The BBC is seeking approval for its iPlayer application, but it seems the launch schedule for this has also been put back again, pending a regulatory market impact assessment. In the interim, ITV plans to launch its own online video service and has appointed renowned interactive design agency Schematic to provide the interface. Channel 4, which is already experimenting with live streaming and downloads, plans to have its service in place by the end of the year.