MPEG-4 is designed for the quality and compression of audio and video files for both computers and mobile devices, including phones.
Director of QuickTime product marketing Casanova said: "Real Networks announcing its support for MPEG-4 is a sudden and abrupt change in direction, but nonetheless, a welcome one.
"We're really happy here at Apple, and, as members of the Internet Streaming Media Alliance, the ISMA, we're delighted Real had decided to make this change."
Casanova also told Creative Mac: "Real is a big company from an Internet media-streaming perspective, and its stamp of approval for MPEG-4 gives it more momentum."
Apple is preparing for its QuickTime Live Conference which starts from February 11 to 14 in the Beverley Hilton Hotel, in Beverly Hills, California. The original event was postponed because of the September 11 atrocities.