Patent ID: 11907611
Assignee: APPLE INC.
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 9:
10. The audio decoder apparatus of claim 1 wherein the processor is configured to
extract from the bitstream the index to the first DRC characteristic and use the extracted index to obtain an inverse of the first DRC characteristic,
recover a loudness sequence by applying the first DRC gain sequence to the inverse of the first DRC characteristic,
if the index has a first predefined value then for each instance of the integrated loudness update, calculate a normalization gain update as a difference between i) a DRC input loudness target and ii) a sum of the instance of the integrated loudness update and the loudness normalization gain, and add the normalization gain update to the recovered loudness sequence to produce a normalized loudness sequence,
produce a second DRC gain sequence by applying the normalized loudness sequence to a second DRC characteristic, and
apply the second DRC gain sequence to the audio signal.