1 files changed, 18 insertions, 0 deletions
diff --git a/src/lib/audio_mapping.cc b/src/lib/audio_mapping.cc
index b1810c973..e35c1ae94 100644
--- a/src/lib/audio_mapping.cc
+++ b/src/lib/audio_mapping.cc
@@ -22,6 +22,7 @@
 #include <libdcp/raw_convert.h>
 #include "audio_mapping.h"
 #include "util.h"
+#include "md5_digester.h"
 
 using std::list;
 using std::cout;
@@ -126,3 +127,20 @@ AudioMapping::as_xml (xmlpp::Node* node) const
 		}
 	}
 }
+
+/** @return a string which is unique for a given AudioMapping configuration, for
+ *  differentiation between different AudioMappings.
+ */
+string
+AudioMapping::digest () const
+{
+	MD5Digester digester;
+	digester.add (_content_channels);
+	for (int i = 0; i < _content_channels; ++i) {
+		for (int j = 0; j < MAX_DCP_AUDIO_CHANNELS; ++j) {
+			digester.add (_gain[i][j]);
+		}
+	}
+
+	return digester.get ();
+}