QuickTime is one of the underlying technologies in Mac OS X, responsible for providing the operating system and third-party applications with services for the playback and editing of various types of multimedia content, such as video and audio, in multiple formats from both devices locally connected to the Macintosh as in Internet streaming.
The new revision 7.5.5 will be available for Tiger (10.4.9 and later), Leopard, Windows XP and Windows Vista operating systems; Panther (10.3) being the big absent from the compatibility list for the first revision that Apple has made available to developers.
