	US 11,930,347 B2
	Adaptive loudness normalization for audio object clustering
Lianwu Chen, Beijing (CN); and Lie Lu, Dublin, CA (US)
Assigned to Dolby Laboratories Licensing Corporation, San Francisco, CA (US)
Appl. No. 17/427,665
Filed by Dolby Laboratories Licensing Corporation, San Francisco, CA (US)
PCT Filed Feb. 12, 2020, PCT No. PCT/US2020/017953 § 371(c)(1), (2) Date Aug. 2, 2021, PCT Pub. No. WO2020/167966, PCT Pub. Date Aug. 20, 2020.
Claims priority of provisional application 62/814,718, filed on Mar. 6, 2019.
Claims priority of application No. PCT/CN2019/074915 (WO), filed on Feb. 13, 2019; and application No. 19161889 (EP), filed on Mar. 11, 2019.
Prior Publication US 2022/0159395 A1, May 19, 2022
Int. Cl. H04S 7/00 (2006.01)

CPC H04S 7/30 (2013.01) [H04S 2400/13 (2013.01)]

24 Claims

1. A method of processing audio content including a plurality of audio elements, the method comprising:

clustering the plurality of audio elements into a plurality of clusters of audio elements; and

for a cluster among the plurality of clusters:

for each audio element in the cluster, determining a measure of energy that the audio element contributes to the cluster;

for at least one audio element in the cluster, determining a compensation gain based at least in part on the measures of energy for the audio elements in the cluster;

applying the compensation gain to the at least one audio element in the cluster, wherein the measure of energy that an audio element contributes to the cluster c is given by E_oc=g_oc²E_o, where E_ois the energy of the audio element and g_ocis the element-to-cluster gain for the audio element o, wherein the element-to-cluster gain is the gain with which the audio element o is rendered to the cluster c;

for the cluster among the plurality of clusters:

determining a first measure of energy of the cluster as a sum of the measures of energy that the audio elements in the cluster contribute to the cluster;

determining a spectrum of the cluster based on respective spectra that the audio elements contribute to the cluster;

determining a second measure of energy of the cluster based on the spectrum of the cluster; and

determining, as at least a part of the compensation gain for each audio element in the cluster, an overall compensation gain for the cluster based on the first measure of energy and the second measure of energy; and

wherein the first measure of energy for the cluster is given by

E_{tot_o}=Σ_oE_oc,

and/or wherein the second measure of energy is given by

E_c=X_c′X_c,

where index o indicates a respective audio element in the cluster, with X_c=Σ_og_ocX_obeing the spectrum of the cluster, X_obeing the spectrum of the respective audio element, and X_c′ indicating the complex conjugate of X_c.