diff --git a/libavcodec/simple_idct.c b/libavcodec/simple_idct.c
index eeb627999c..8957ef566b 100644
--- a/libavcodec/simple_idct.c
+++ b/libavcodec/simple_idct.c
@@ -161,7 +161,8 @@ static inline void idct4col_add(uint8_t *dest, int line_size, const int16_t *col
 #define R_SHIFT 11
 static inline void idct4row(int16_t *row)
 {
-    int c0, c1, c2, c3, a0, a1, a2, a3;
+    unsigned c0, c1, c2, c3;
+    int a0, a1, a2, a3;
 
     a0 = row[0];
     a1 = row[1];