mpegts: check av_new_stream() return value.

Fixes CID703728
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/mpegts.c

@@ -1505,6 +1505,8 @@ static void pmt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
             pes = ts->pids[pid]->u.pes_filter.opaque;
             if (!pes->st) {
                 pes->st = avformat_new_stream(pes->stream, NULL);
+                if (!pes->st)
+                    goto out;
                 pes->st->id = pes->pid;
             }
             st = pes->st;
@@ -1513,6 +1515,8 @@ static void pmt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
             pes = add_pes_stream(ts, pid, pcr_pid);
             if (pes) {
                 st = avformat_new_stream(pes->stream, NULL);
+                if (!st)
+                    goto out;
                 st->id = pes->pid;
             }
         } else {
@@ -1521,6 +1525,8 @@ static void pmt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
                 st = ts->stream->streams[idx];
             } else {
                 st = avformat_new_stream(ts->stream, NULL);
+                if (!st)
+                    goto out;
                 st->id = pid;
                 st->codec->codec_type = AVMEDIA_TYPE_DATA;
             }