Microsoft is announcing new technology for online media applications, designed to take on web and design tools vendor, Adobe.

The Silverlight browser plug-in will allow web content providers to offer rich video and interactive media experience direct from their sites, according to Forest Key, a director of product management for Microsoft's Server and Tools Division. The technology, which builds on Vista's new graphics framework Windows Presentation Foundation (WPF), will debut at the National Association of Broadcasters (NAB) conference in Las Vegas this week.

Silverlight - formerly code-named WPF/E - is compatible with browsers including Internet Explorer (IE), Safari and Firefox, and should give a similar user experience with IE 7 running on Windows Vista, and with Firefox running on an Apple Mac computer. A big benefit of the technology for end users is that they will not have to download different video player technology to view online media based on what OS they are running, Key said.

Silverlight is aimed at three core audiences: content providers that want to distribute video and rich media over the web; designers and developers that are building rich interactive applications; and end users that want enhanced web-based media viewing.

Content providers who have signed up for Silverlight, include Akamai, Brightcove, Eyeblaster, Major League Baseball and Netflix.

Microsoft is highlighting the video-delivery capabilities of Silverlight at NAB, but the company plans to show how organisations can use Silverlight in a similar way to Adobe's Flash to deliver web-based applications using animation and other rich media, Key said.

Microsoft also plans to optimise other components of its software platform to add value to Silverlight. For example, the forthcoming Windows Server, codenamed Longhorn, will include as a plug-in the IIS7 Media Pack, which adds new features to enhance and reduce the cost of delivering rich media over the web.

Microsoft's Expression toolset to build rich internet applications, which Microsoft is touting as an alternative to Adobe's recently released Creative Suite 3, is also key to Silverlight because designers will use it to create applications to be delivered through the technology. Expression should be generally available in June.

Keith Cutcliffe, IT developer and analyst for US-based ProAssurance is skeptical that Microsoft will ever gain the faithful user base Adobe has. However, he said that enterprise customers that have developed Flash applications to run on Microsoft-based web infrastructure eventually may use Silverlight and Expression instead because of the underlying back-end platform ties.

Scott Stanfield, CEO of application development firm Vertigo Software, seems supportive of that sentiment. He said Silverlight fills a major gap in Microsoft's strategy to provide a mechanism to deliver and build applications that provide the stability of desktop applications with the user experience of media-rich web applications.

"Previously Flash was the only answer," he said. "Now Silverlight becomes a viable alternative."

Microsoft will deliver a beta of Silverlight at the end of April, and will announce plans for general availability at that time, Key said.