Apple has announced that more than 250 million copies of QuickTime 6 have been downloaded in the two years since its release, making it the most popular version of QuickTime ever distributed.

Apple’s senior vice president of worldwide product marketing Philip Schiller said: "With QuickTime 6, Apple continues to be the industry leader in providing an end-to-end standards-based digital media delivery system."

QuickTime was chosen by the International Organization for Standardization (ISO) as the base file format for MPEG-4 and is at the core of the 3GPP and 3GPP2 standards – it includes enhanced support for 3GPP and 3GPP2 mobile networks.

It is available as a free download for Mac and Windows users from Apple's Web site.