downgrade mov negative ctts log message to warning, patch by Art Clarke, aclarke at vlideshow dot com

Originally committed as revision 14492 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/mov.c

@@ -1125,7 +1125,7 @@ static int mov_read_ctts(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
         int duration =get_be32(pb);
 
         if (duration < 0) {
-            av_log(c->fc, AV_LOG_ERROR, "negative ctts, ignoring\n");
+            av_log(c->fc, AV_LOG_WARNING, "negative ctts, ignoring\n");
             sc->ctts_count = 0;
             url_fskip(pb, 8 * (entries - i - 1));
             break;