Index: libs/libavcodec/ac3dec.c
===================================================================
--- libs/libavcodec/ac3dec.c	(revision 20609)
+++ libs/libavcodec/ac3dec.c	(working copy)
@@ -91,6 +91,16 @@
     LEVEL_MINUS_9DB
 };
 
+static const float gain_tweek[7] = {
+    LEVEL_ONE,
+    LEVEL_ONE,
+    LEVEL_ONE,
+    LEVEL_ONE,
+    2,
+    3.16,
+    3.16
+};
+
 /**
  * Table for center mix levels
  * reference: Section 5.4.2.4 cmixlev
@@ -1111,7 +1121,7 @@
 
     /* apply scaling to coefficients (headroom, dynrng) */
     for(ch=1; ch<=s->channels; ch++) {
-        float gain = s->mul_bias / 4194304.0f;
+        float gain = s->mul_bias * gain_tweek[s->channels] / 4194304.0f;
         if(s->channel_mode == AC3_CHMODE_DUALMONO) {
             gain *= s->dynamic_range[ch-1];
         } else {