AAC Evolution

During the long lifespan of AAC, there have been three updates which have added the latest technological advancements while maintaining full compatibility with the existing AAC format. These updates create increased efficiency, which means fewer bits have to be spent to achieve the same excellent audio quality as before.

Evolution of AAC in a backward compatible manner: the original profile is part of all successors. In parallel a low delay line has been developed (image-source: Fraunhofer IIS)

AAC was always updated in a backward compatible manner. AAC files that have been bought from itunes 10 years ago still play on the latest generation of portable music players and they still will for next 100 years. (image-source: Fraunhofer IIS)