Basic support for calculating audio gains based on the sound processor's gain curve.

[dcpomatic.git] / src / lib / dolby_cp750.cc

diff --git a/src/lib/dolby_cp750.cc b/src/lib/dolby_cp750.cc
new file mode 100644 (file)
index 0000000..262e57b
--- /dev/null
+++ b/src/lib/dolby_cp750.cc
@@ -0,0 +1,58 @@
+/*
+    Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include "dolby_cp750.h"
+
+using namespace std;
+
+DolbyCP750::DolbyCP750 ()
+       : SoundProcessor ("dolby_cp750", "Dolby CP750")
+{
+
+}
+
+float
+DolbyCP750::db_for_fader_change (float from, float to) const
+{
+       float db = 0;
+
+       if (from < to) {
+               if (from <= 4) {
+                       float const t = min (to, 4.0f);
+                       db += (t - from) * 20;
+               }
+               
+               if (to > 4) {
+                       float const t = max (from, 4.0f);
+                       db += (to - t) * 3.33333333333333333;
+               }
+       } else {
+               if (from >= 4) {
+                       float const t = max (to, 4.0f);
+                       db -= (from - t) * 3.33333333333333333;
+               }
+
+               if (to < 4) {
+                       float const t = min (from, 4.0f);
+                       db -= (t - to) * 20;
+               }
+       }
+
+       return db;
+}