Patent ID: 9159330
Filing Date: 2015-10-13
Classification: G10L

Abstract:
1. In an audio encoding system that divides frames generated from input signals into multiple scale factor bands and that encodes each of said multiple scale factor bands by using a scale factor, a rate control apparatus that performs rate controls based upon an NMR which is the ratio of noise energy to mask energy based on a predetermined auditory psychological model, wherein said rate control apparatus comprises: an NMR determination unit that determines, by a binary search, an NMR that does not exceed a target rate; and a scale factor determination unit that determines, for each scale factor band and by a binary search, the maximum scale factor that corresponds to the NMR that was determined by said NMR determination unit; wherein each time said NMR determination unit selects an NMR candidate value that acts as a candidate when the NMR is searched for by a binary search, said scale factor determination unit determines a scale factor and a rate with respect to said NMR candidate value; and wherein said NMR determination unit determines as the optimal NMR the smallest NMR that does not exceed a target rate, based upon the difference between the rate with respect to said NMR candidate value that was calculated based on the scale factor determined by said scale factor determination unit and said target rate.