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Gadgets get connected with DLNA

The long-promised dream of a home-wide network that allows gadgets to seamlessly interconnect may soon become a reality.

That's because products based on a new home networking specification backed by some of the world's largest consumer electronics and computer companies will be available before the end of this year, some of the same companies said at last week's Ceatec Japan 2004 show.

The specification was drawn up by a group called the Digital Living Network Alliance (DLNA), known until earlier this year as the Digital Home Working Group. The group which encompasses more than 180 companies, including Intel, Microsoft, Sony, Nokia and Hewlett-Packard, published version 1.0 of its standard in June.

"This is the quickest time from standardisation to implementation in products that I have experienced," said Scott Smyers, chairman of the DLNA board of directors and vice-president of Sony Electronics' network and systems architecture division.

Part of the reason for this fast pace is due to the specification's reliance on existing standards.

The first version calls for a network based on wired or wireless Ethernet and running Internet Protocol version 4. Media is carried across the network using HTTP and discovery, control and management of connected devices is accomplished with universal plug-and-play.

To fulfill the promise of the digital home network, device interconnection is only one step.

Another important step is getting the devices to speak the same language, which in multimedia terms means to exchange data in the same format.

In the first version of the DLNA specification the JPeg image, Liner PCM audio and MPeg2 video protocols have been set as a common base. Products can use other formats internally but must be able to transcode them to one of the base formats for interconnection purposes.

Several demonstration networks, each featuring a handful of products supporting DLNA, were on show at Ceatec Japan.

On one network, a Toshiba TV tuner was connected to an NEC PC, Panasonic notebook PC and Sony television via Ethernet and to a Toshiba notebook PC, Sony handheld digital media player and Netgear digital media player via wireless Ethernet. Users of each device could browse the network and access content stored on other devices.

"When we agree on standards, we are successful," said Louis Burns, vice-president and general manager of Intel's desktop platforms group. "We've already made great progress in developing standards for the digital home."

In today's digital world, setting common formats for both interconnection and files is not enough. As users of online music download services have already discovered, digital rights management systems can stop content sharing cold even if the files are based on the same format.

Here work is also taking place, although at present it is outside of the DLNA.

One system, called Digital Transmission Content Protection/Internet Protocol (DTCP/IP), is being developed by Intel, Hitachi, Sony, Toshiba and Matsushita Electric. It has been developed to protect content as it is transmitted across an IP network like that used by DLNA products.

Developers of the system are working with digital rights management owners on transcoding that would also allow sharing of content between devices that support different DRM systems - something that isn't possible at present.

Using DTCP/IP and transcoding, for example, copy-protected music from Apple Computer's iTunes Music Store would be able to be streamed across a network to a digital music player that supports only Microsoft's Windows Media Audio DRM.

The system would transcode the Apple DRM into DTCP/IP for transmission across and network and transcode it to Windows Media DRM at the other end, ensuring it remains protected but can be shared.

Digital 5 was demonstrating this at Ceatec with a prototype set-top box from Netgear. The MP115 contains Digital 5's middleware and will be launched before the end of this year, said Alexander Markovic, principal technologist at Digital 5.

It will allow consumers to Movielink's online movies-on-demand service to download content to their PC and stream it to the Netgear box for viewing on a television. The DTCP transcodes from Real Networks's DRM to DTCP/IP for transmission across the network.

Looking ahead, DLNA is now working on a version 1.1 specification and addendums that will cover a number of optional media formats, including Gif, PNG and Tiff images, MP3, Windows Media Audio, AC-3, AAC and ATRAC3, plus audio and the MPeg4 Part 2, MPeg4 Part 10 and Windows Media Video 9 video formats.

The optional formats will mean no transcoding is required in the case that two devices support MP3, for example. The devices will still be required to support the mandatory formats so they can exchange data with devices that don't support the optional format in question.

Martyn Williams writes for IDG News Service


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