Apple delivered the largest ever MPEG-4 webcast – with CEO Steve Jobs' Macworld Expo keynote being streamed to 50,000 people.

A total of 25,000 of these viewers watched the MPEG-4 supporting QuickTime 6 feed, with the remainder using version 5 to watch the July 17 address.

Apple used four Xserves running QuickTime Streaming Server 4.1 and QuickTime Broadcaster to deliver the event.

Apple's VP of worldwide product marketing Phil Schiller said: “The keynote webcast was a major landmark in Internet streaming, one made possible by QuickTime 6's end-to-end support for the open-standard MPEG-4.

“With MPEG-LA's recent release of reasonable licensing terms, MPEG-4 will succeed as the open format for creating and streaming content to PCs and digital devices.”

QuickTime 6 is available as a free download for Mac and Windows users.