Complex sentence: AAC was developed with the cooperation and contributions of companies including AT&T Bell Laboratories, Fraunhofer IIS, Dolby, Sony Corporation and Nokia, and was officially declared an international standard by the Moving Picture Experts Group in April 1997.
Split into simpler sentences: AAC was developed with the cooperation and contributions of companies including AT&T Bell Laboratories, Fraunhofer IIS, Dolby Laboratories, Sony Corporation and Nokia. It was officially declared an international standard by the Moving Picture Experts Group in April 1997.