diff --git a/libavformat/id3v2.c b/libavformat/id3v2.c
index cbf43757fe..42c72477aa 100644
--- a/libavformat/id3v2.c
+++ b/libavformat/id3v2.c
@@ -204,7 +204,7 @@ static int check_tag(AVIOContext *s, int offset, unsigned int len)
 
     if (len > 4 ||
         avio_seek(s, offset, SEEK_SET) < 0 ||
-        avio_read(s, tag, len) < len)
+        avio_read(s, tag, len) < (int)len)
         return -1;
     else if (!AV_RB32(tag) || is_tag(tag, len))
         return 1;