Microsoft tries to outshine Flash with Silverlight

Microsoft is preparing to announce the first public release of Silverlight, the new name for what was formerly Windows Presentation Foundation Everywhere, or WPF/E. The technologies will be formally announced at the Mix07 conference, which starts on April 30 in Las Vegas.

Silverlight is a set of technologies that are based on the Windows Presentation Foundation programming interfaces that shipped with Windows Vista. Formerly codenamed Avalon, the WPF toolkit allows all sorts of different multimedia types to be displayed on the screen, including vector graphics and video files. The language used to construct WPF objects is Microsoft's XAML, a XML-based user interface composition language. The idea behind WPF was to cleanly separate the user interface from the program itself. WPF/E was intended to be a cross-platform version of WPF that didn't have all the features of WPF, such as 3D acceleration support.

Now, with the fancy new Silverlight name, Microsoft is planning on positioning Silverlight as a replacement for other web-based graphics technologies, such as Adobe's Flash. Microsoft is pushing the fact that Silverlight can deliver streaming videos encoded with its own VC-1 codec, which can be delivered in up to 720 lines of resolution. Flash, currently the king of streaming video on the Internet thanks to YouTube, is limited to 576 lines.

Microsoft's plan is to entice web developers over to Silverlight gradually, emphasizing that they can leverage existing skills with HTML, Javascript, AJAX, and XAML. The company plans to release a suite of Silverlight development tools to make this process easier. Tools such as Microsoft's Expression XAML builder (currently in beta) can also be used to create Silverlight presentations. While Silverlight is cross-platform in terms of web browser support, the development tools are Windows-only.

On the server side, Silverlight applications will work fine with Linux-based web servers, but Microsoft is encouraging people to use Windows-based servers by bundling extra tools to make the process easier. Windows Server "Longhorn"—the server version of Vista expected to ship later this year—will come with Streaming Media Services for deploying VC-1 video for Silverlight clients.