diff --git a/libswscale/swscale.c b/libswscale/swscale.c
index 0e86af9cf5..0987f4d1e5 100644
--- a/libswscale/swscale.c
+++ b/libswscale/swscale.c
@@ -1111,8 +1111,8 @@ static inline void rgb48ToY(uint8_t *dst, const uint8_t *src, int width,
 }
 
 static inline void rgb48ToUV(uint8_t *dstU, uint8_t *dstV,
-                             uint8_t *src1, uint8_t *src2, int width,
-                             uint32_t *unused)
+                             const uint8_t *src1, const uint8_t *src2,
+                             int width, uint32_t *unused)
 {
     int i;
     assert(src1==src2);
@@ -1127,8 +1127,8 @@ static inline void rgb48ToUV(uint8_t *dstU, uint8_t *dstV,
 }
 
 static inline void rgb48ToUV_half(uint8_t *dstU, uint8_t *dstV,
-                                  uint8_t *src1, uint8_t *src2, int width,
-                                  uint32_t *unused)
+                                  const uint8_t *src1, const uint8_t *src2,
+                                  int width, uint32_t *unused)
 {
     int i;
     assert(src1==src2);