diff --git a/libavcodec/utvideoenc.c b/libavcodec/utvideoenc.c
index 36dcb8283a..ad8d73fbb4 100644
--- a/libavcodec/utvideoenc.c
+++ b/libavcodec/utvideoenc.c
@@ -239,7 +239,7 @@ static av_cold int utvideo_encode_init(AVCodecContext *avctx)
      * - Compression mode (none/huff)
      * And write the flags.
      */
-    c->flags  = (c->slices - 1) << 24;
+    c->flags  = (c->slices - 1U) << 24;
     c->flags |= 0 << 11; // bit field to signal interlaced encoding mode
     c->flags |= c->compression;