diff --git a/libavcodec/sanm.c b/libavcodec/sanm.c
index e6e866ef8e..d1ef0ce2a1 100644
--- a/libavcodec/sanm.c
+++ b/libavcodec/sanm.c
@@ -1044,8 +1044,10 @@ static int decode_5(SANMVideoContext *ctx)
 #if HAVE_BIGENDIAN
     npixels = ctx->npixels;
     frm = ctx->frm0;
-    while (npixels--)
-        *frm++ = av_bswap16(*frm);
+    while (npixels--) {
+        *frm = av_bswap16(*frm);
+        frm++;
+    }
 #endif
 
     return 0;