diff --git a/libavformat/vividas.c b/libavformat/vividas.c
index 9617b10c0a..23f010d25c 100644
--- a/libavformat/vividas.c
+++ b/libavformat/vividas.c
@@ -131,7 +131,7 @@ static void xor_block(void *p1, void *p2, unsigned size, int key, unsigned *key_
     size >>= 2;
 
     while (size > 0) {
-        *d2 = *d1 ^ (HAVE_BIGENDIAN ? av_bswap32(k) : k);
+        AV_WN32(d2, AV_RN32(d1) ^ (HAVE_BIGENDIAN ? av_bswap32(k) : k));
         k += key;
         d1++;
         d2++;