diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index baa9597977..e792eaf163 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -328,10 +328,10 @@ static void compute_rematrixing_strategy(AC3EncodeContext *s)
                 CoefType rt = block->mdct_coef[1][i];
                 CoefType md = lt + rt;
                 CoefType sd = lt - rt;
-                sum[0] += lt * lt;
-                sum[1] += rt * rt;
-                sum[2] += md * md;
-                sum[3] += sd * sd;
+                sum[0] += MUL_COEF(lt, lt);
+                sum[1] += MUL_COEF(rt, rt);
+                sum[2] += MUL_COEF(md, md);
+                sum[3] += MUL_COEF(sd, sd);
             }
 
             /* compare sums to determine if rematrixing will be used for this band */
diff --git a/libavcodec/ac3enc_fixed.h b/libavcodec/ac3enc_fixed.h
index 12c8ace4aa..773caec2c3 100644
--- a/libavcodec/ac3enc_fixed.h
+++ b/libavcodec/ac3enc_fixed.h
@@ -36,6 +36,8 @@ typedef int16_t SampleType;
 typedef int32_t CoefType;
 typedef int64_t CoefSumType;
 
+#define MUL_COEF(a,b) MUL64(a,b)
+
 
 /**
  * Compex number.
diff --git a/libavcodec/ac3enc_float.h b/libavcodec/ac3enc_float.h
index 1726ca045f..6ad22ecc0b 100644
--- a/libavcodec/ac3enc_float.h
+++ b/libavcodec/ac3enc_float.h
@@ -36,6 +36,8 @@ typedef float SampleType;
 typedef float CoefType;
 typedef float CoefSumType;
 
+#define MUL_COEF(a,b) ((a)*(b))
+
 
 typedef struct AC3MDCTContext {
     const float *window;    ///< MDCT window function