diff --git a/libavcodec/wavpack.h b/libavcodec/wavpack.h
index 0196574aab..445d593c3b 100644
--- a/libavcodec/wavpack.h
+++ b/libavcodec/wavpack.h
@@ -99,8 +99,8 @@ typedef struct WvChannel {
 
 // macros for manipulating median values
 #define GET_MED(n) ((c->median[n] >> 4) + 1)
-#define DEC_MED(n) c->median[n] -= ((c->median[n] + (128 >> (n)) - 2) / (128 >> (n))) * 2
-#define INC_MED(n) c->median[n] += ((c->median[n] + (128 >> (n))    ) / (128 >> (n))) * 5
+#define DEC_MED(n) c->median[n] -= ((c->median[n] + (128 >> (n)) - 2) / (128 >> (n))) * 2U
+#define INC_MED(n) c->median[n] += ((c->median[n] + (128 >> (n))    ) / (128 >> (n))) * 5U
 
 // macros for applying weight
 #define UPDATE_WEIGHT_CLIP(weight, delta, samples, in) \