US Patent 10276173 Encoded audio extended metadata-based dynamic range control

An audio encoder encodes a digital audio recording having a number of audio channels or audio objects. A Dynamic Range Control (DRC) processor produces a sequence of encoder DRC gain values, by applying a selected one of a number of DRC characteristics to a group of one or more of the audio channels or audio objects. The encoder DRC gain values are to be applied to adjust the group of audio channels or audio objects, upon decoding them from the encoded digital audio recording. A bitstream multiplexer combines a) the encoded digital audio recording with b) the sequence of encoder DRC gain values, an indication of the selected DRC characteristic, and an indication of an alternate DRC characteristic, the latter as metadata associated with the encoded digital audio recording. Other embodiments are also described including a system for decoding the encoded audio recording and performing DRC adjustment upon it.