avformat/mlvdec: Check the return code from strftime()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/mlvdec.c

@@ -204,7 +204,7 @@ static int scan_file(AVFormatContext *avctx, AVStream *vst, AVStream *ast, int f
             time.tm_yday   = avio_rl16(pb);
             time.tm_isdst  = avio_rl16(pb);
             avio_skip(pb, 2);
-            strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", &time);
+            if (strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", &time))
                 av_dict_set(&avctx->metadata, "time", str, 0);
             size -= 20;
         } else if (type == MKTAG('E','X','P','O') && size >= 16) {