Loudness uniformity and dynamic range control for digital multichannel audio broadcasting

High quality digital multichannel sound is now becoming available to consumers in their homes by means of a variety of both broadcast and packaged media which employ the AC-3 bit-rate reduction system. The initial implementation of AC-3 was for the cinema application where the goal was to encode a 5.1 channel film soundtrack specifically for reproduction in a cinema. In order to apply the AC-3 coder to domestic consumer applications several desirable features were added. The goal for the consumer application was to provide an encoded bit stream which could easily be used by a wide variety of consumers, ranging from those who wish to reproduce the cinema experience in the home, to those who simply wish to enjoy the audio program content with a limited dynamic range reproduction, free from unwanted loudness variations. The features of AC-3 which make this possible will be described