Patent ID: 9565508
Date: 2017-02-07
CPC Classifications: H03G,H04R,H04S

Claim:
1. A loudness signal processor for processing an input audio signal in order to control a resulting integrated loudness level and a resulting loudness range of an output audio signal by a predetermined target loudness level and by a predetermined target loudness range, the loudness signal processor comprising an input arranged to receive an input audio signal; a level detector block arranged to determine a time-varying level of said input audio signal; a distribution analyzer block arranged to estimate a time-varying level distribution of said time-varying level; a transfer function generator block arranged to determine a time-varying transfer function on the basis of said time-varying level distribution, and said predetermined target loudness level and said predetermined target loudness range; a gain control block arranged to calculate a time-varying gain on the basis of said time-varying level of the input audio signal and said time-varying transfer function; a multiplier block arranged to apply said time-varying gain to said input audio signal, resulting in said output audio signal, wherein said transfer function generator block is arranged to determine a loudness level estimated on the basis of said time-varying level distribution by performing an RMS calculation in which the levels below a threshold are excluded, as specified in the calculation of integrated, gated loudness level of ITU-R BS-1770-2 and EBU R-128.