As part of the deal, the companies will carry out joint research and development to ensure that products from Real, such as its RealOne software, work well with consumer gadgets from Sony.
Real will continue to incorporate Sony media technologies such as its Adaptive Transform Acoustic Coding (ATRAC3) audio compression system with future Real software.
Sony also agreed to purchase a minority stake of 1% in RealNetworks, the companies said in a statement.
Sony and RealNetworks have been partners on digital media since early 2000 when they announced a similar agreement to use each other's products and technologies.
Last May Sony's Computer Entertainment division said it would embed RealPlayer in the PlayStation 2, allowing users to view content downloaded from the Internet on its gaming console.
The deal is non-exclusive, meaning Sony is also free to work with RealNetworks rivals such as Microsoft, Turner said. "But Sony is a natural ally for RealNetworks," he added.