1 files changed, 11 insertions, 0 deletions
diff --git a/libavcodec/ac3.h b/libavcodec/ac3.h
index e653b2e95d..133c5b9a78 100644
--- a/libavcodec/ac3.h
+++ b/libavcodec/ac3.h
@@ -48,6 +48,17 @@
 #define EXP_D25   2
 #define EXP_D45   3
 
+/* pre-defined gain values */
+#define LEVEL_PLUS_3DB          1.4142135623730950
+#define LEVEL_PLUS_1POINT5DB    1.1892071150027209
+#define LEVEL_MINUS_1POINT5DB   0.8408964152537145
+#define LEVEL_MINUS_3DB         0.7071067811865476
+#define LEVEL_MINUS_4POINT5DB   0.5946035575013605
+#define LEVEL_MINUS_6DB         0.5000000000000000
+#define LEVEL_MINUS_9DB         0.3535533905932738
+#define LEVEL_ZERO              0.0000000000000000
+#define LEVEL_ONE               1.0000000000000000
+
 /** Delta bit allocation strategy */
 typedef enum {
     DBA_REUSE = 0,