ffmpeg: Print an error instead of a debug message on exit.

Reported-by: Forum user NewPlaza

fftools/ffmpeg.c

@@ -788,6 +788,8 @@ static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int u
             int64_t max = ost->last_mux_dts + !(s->oformat->flags & AVFMT_TS_NONSTRICT);
             if (pkt->dts < max) {
                 int loglevel = max - pkt->dts > 2 || st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO ? AV_LOG_WARNING : AV_LOG_DEBUG;
+                if (exit_on_error)
+                    loglevel = AV_LOG_ERROR;
                 av_log(s, loglevel, "Non-monotonous DTS in output stream "
                        "%d:%d; previous: %"PRId64", current: %"PRId64"; ",
                        ost->file_index, ost->st->index, ost->last_mux_dts, pkt->dts);