Internal Microsoft documentation states that the software giant is about to make a surprising addition to the Windows Vista code tree on February 22, about a week after the company is expected to ship a complete version of the OS to testers. On that day, the company will apparently add Blu-ray DVD support to the OS, according to the documentation I've seen.

There's just one problem: The software giant denies it will support Blu-ray.

"There are still no plans for any development work on \[Blu-ray\] from Microsoft," a company spokesperson told me on Wednesday. "Since Windows is a platform, they expect companies to provide \[Blu-ray\] solutions for Windows Vista." The company pointed me to work that Cyberlink is doing with its XP-based Blu-ray video editing, playback, and disc-burning solution as an example of the type of third-party products it expects to see for Vista as well.

Coincidentally, on Wednesday, Microsoft publicly denied any chance that it will include native Blu-ray support in Vista. Noting that it had "absolutely no plans" to support Blu-ray, Microsoft said it "firmly stands behind the HD-DVD format as the best choice for our consumers."

According to the internal documentation I've seen, Blu-ray DVD support was initially set for inclusion in late January Vista builds, then the timing was pushed back to late February. This week, Microsoft neared completion of the feature-complete Vista build it will release as the February Community Technology Preview (CTP) build to testers. This build will include new features such as Windows Sidebar, various antimalware technologies, and a Remote Desktop feature that supports Aero Glass with no performance penalty. To date, almost 60 development teams at Microsoft have submitted code for the feature-complete Vista build.

Update: Microsoft has elected to clarify what it is they're really doing. Adam Anderson, a product manager in the Windows division, told me, "Microsoft is adding the ability to detect a movie disc for a variety of optical formats, which is known as AutoPlay, since OEMs will have a choice of which drive they want to place in their PCs. The HD-DVD AutoPlay feature is already implemented and Blu-Ray's is under study. This simply recognizes the particular media that you put into the disc drive, so implementing this feature for Blu-Ray does not constitute native or platform support for Blu-Ray in Vista.  As stated before, we will leave that up to third party developers." In short, Windows Vista will support (i.e. recognize) Blu-Ray discs, but will not natively support Blu-Ray movie playback; for that, you'll still need third party software.