b@0: function factor = loudness_match (X, fs, lkfs)
b@0: %LOUDNESS_MATCH
b@0: %   LOUDNESS_MATCH (X, fs, lkfs) calculates an amplitude multiplication factor
b@0: %   which equalizes a sound to match the specified loudness (in LKFS).
b@0: %
b@0: %   2010-02-23 by MARUI Atsushi
b@0: 
b@0: factor = 1.0;
b@0: factorHigh = 10^(+60/20);
b@0: factorLow = 10^(-60/20);
b@0: i = 1;
b@0: 
b@0: while i
b@0:     s = loudness_itu(factor * X, fs);
b@0:     k = (s - lkfs) / lkfs;
b@0:     
b@0:     fprintf('%3d:   Factor %7.5f   LKFS %7.3f   (%6.2f%% difference)\n', i, factor, s, k*100);
b@0:     i = i + 1;
b@0:     
b@0:     if abs(k) < 0.001
b@0:         return;
b@0:     end
b@0:     
b@0:     if k < 0.0
b@0:         factorOld = factor;
b@0:         factor = (factorLow + factor) / 2.0;
b@0:         factorHigh = factorOld;
b@0:     elseif k > 0.0
b@0:         factorOld = factor;
b@0:         factor = (factorHigh + factor) / 2.0;
b@0:         factorLow = factorOld;
b@0:     end
b@0: end