diff aux/loudness_match.m @ 0:4fd284285159

Adding listening test plus some helpful functions and scripts.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/aux/loudness_match.m	Thu Apr 24 23:53:31 2014 +0100
@@ -0,0 +1,33 @@
+function factor = loudness_match (X, fs, lkfs)
+%LOUDNESS_MATCH
+%   LOUDNESS_MATCH (X, fs, lkfs) calculates an amplitude multiplication factor
+%   which equalizes a sound to match the specified loudness (in LKFS).
+%
+%   2010-02-23 by MARUI Atsushi
+
+factor = 1.0;
+factorHigh = 10^(+60/20);
+factorLow = 10^(-60/20);
+i = 1;
+
+while i
+    s = loudness_itu(factor * X, fs);
+    k = (s - lkfs) / lkfs;
+    
+    fprintf('%3d:   Factor %7.5f   LKFS %7.3f   (%6.2f%% difference)\n', i, factor, s, k*100);
+    i = i + 1;
+    
+    if abs(k) < 0.001
+        return;
+    end
+    
+    if k < 0.0
+        factorOld = factor;
+        factor = (factorLow + factor) / 2.0;
+        factorHigh = factorOld;
+    elseif k > 0.0
+        factorOld = factor;
+        factor = (factorHigh + factor) / 2.0;
+        factorLow = factorOld;
+    end
+end
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