diff --git a/libavcodec/wavarc.c b/libavcodec/wavarc.c
index 2e32b46ebd..6941ba9ab5 100644
--- a/libavcodec/wavarc.c
+++ b/libavcodec/wavarc.c
@@ -154,11 +154,11 @@ static void do_stereo(WavArcContext *s, int ch, int correlated, int len)
     } else {
         if (correlated) {
             for (int n = 0; n < nb_samples; n++)
-                s->samples[1][n + len] += s->samples[0][n + len];
+                s->samples[1][n + len] += (unsigned)s->samples[0][n + len];
         }
         for (int n = 0; n < len; n++) {
             s->pred[0][n] = s->samples[1][nb_samples + n];
-            s->pred[1][n] = s->pred[0][n] - s->samples[0][nb_samples + n];
+            s->pred[1][n] = s->pred[0][n] - (unsigned)s->samples[0][nb_samples + n];
         }
     }
 }