Microsoft on Monday announced a prerelease version of a new cross-platfrom browser plug-in called Silverlight that will provide Web designers with a way to add high-quality video and animations to their sites. The technology competes directly with Adobe Flash and, to a lesser extent, with Apple QuickTime. But this isn't the first time Microsoft and Adobe have found themselves at odds with each other. The release of Silverlight suggests that, at last, the gloves are off.

Adobe's Flash has been available for about a decade and, despite some technical issues, it's become a de facto standard of sorts for delivering animated content online. (In much the same way, Adobe PDF has become an online standard for delivering documents.) In recent years, Flash has been enhanced to deliver small, low-quality videos. The success of this format can be seen on sites like YouTube, which has become so popular it was recently purchased by online goliath Google.

Silverlight seeks to eliminate various Flash deficiencies by offering much higher quality video and better in-player controls. Microsoft says that Silverlight supports up to 720p video--1280 x 720 resolution--at much higher quality than is possible with Flash. And unlike Flash, Silverlight won't require any expensive back-end servers for companies wishing to rollout the technology. And surprisingly, for a Microsoft product, Silverlight supports all major Web browsers, including Internet Explorer, Firefox, and even Apple Safari, which runs only on the Mac.

Silverlight uses vector graphics for higher quality, Microsoft says, and can be used to display text, graphics, video, and video with text and graphic overlays. It will work with existing Web technologies such as Apache, PHP, JavaScript, and XHTML. Microsoft is also creating various Expression tools for creating and deploying Silverlight content, though these will be Windows-only.

Adobe says content creators can't trust the software giant. "Microsoft has never demonstrated a commitment to maintaining a cross-platform solution," Adobe CEO Bruce Chizen said, suggesting that Microsoft may eventually halt development of Mac-oriented versions of the software as it did with Mac versions of Windows Media Player and IE. Not coincidentally, Adobe has responded to recent interest in using Flash as a delivery vehicle for video with a new desktop player called Flash Video. It's due later this year, and is cross-platform.

Partners in some respects, Adobe and Microsoft increasingly find themselves competing in the same markets. Adobe complained to antitrust regulators last year that Microsoft's bundling of its XML Paper Specification (XPS) format in Windows Vista and Office 2007 was unfair, as it closely resembles Adobe's PDF technologies. And Microsoft's new Expression Design tool competes directly with Adobe Photoshop. Now, with Silverlight, Microsoft is again going after a key Adobe market, and this time, Microsoft is offering a cross-platform solution that actually offers some obvious benefits over the entrenched Adobe entry. Should be an interesting fight.