Publisher's description of Adobe Flash Player 9
From Adobe Systems:
Note: Beta or prerelease software is intended for advanced users and developers only. Normal Flash users should download the latest stable release.
Note: You must uninstall any prior versions of Flash Player in order to install Flash Player beta 9.
Adobe Flash Player is the high-performance, lightweight, highly expressive client runtime that delivers powerful and consistent user experiences across major operating systems, browsers, mobile phones, and devices.
Adobe Labs features prerelease versions of the Flash Player 9 Update software. The beta is an opportunity for developers and consumers to test and provide early feedback to Adobe on new features, enhancements, and compatibility with previously authored content.
This update, codenamed Moviestar, includes new features, enhancements and bug fixes for Windows, Macintosh, and Linux versions of Flash Player 9, including: support for H.264 video and HE-AAC audio codecs; multi-core support for vector rendering; full screen mode with hardware scaling; Flash Player cache for common platform components, such as the Flex framework.