mpegts: pass MpegTSContext ptr explicitly

AVFormatContext->priv_data is not always a MpegTSContext, it can be
RTSPState when decoding a RTP stream. So it is necessary to pass
MpegTSContext pointer explicitly.

Within libav, the write_section_data function doesn't actually use
the MpegTSContext at all, so this doesn't change anything at the
moment (no memory was corrupted before), but it reduces the risk of
anybody trying to touch the MpegTSContext via AVFormatContext->priv_data
in the future.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/mpegts.c

@@ -287,7 +287,7 @@ static int discard_pid(MpegTSContext *ts, unsigned int pid)
  *  Assemble PES packets out of TS packets, and then call the "section_cb"
  *  function when they are complete.
  */
-static void write_section_data(AVFormatContext *s, MpegTSFilter *tss1,
+static void write_section_data(MpegTSContext *ts, MpegTSFilter *tss1,
                                const uint8_t *buf, int buf_size, int is_start)
 {
     MpegTSSectionFilter *tss = &tss1->u.section_filter;
@@ -1704,7 +1704,6 @@ static void sdt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
 /* handle one TS packet */
 static int handle_packet(MpegTSContext *ts, const uint8_t *packet)
 {
-    AVFormatContext *s = ts->stream;
     MpegTSFilter *tss;
     int len, pid, cc, expected_cc, cc_ok, afc, is_start, is_discontinuity,
         has_adaptation, has_payload;
@@ -1774,7 +1773,7 @@ static int handle_packet(MpegTSContext *ts, const uint8_t *packet)
                 return 0;
             if (len && cc_ok) {
                 /* write remaining section bytes */
-                write_section_data(s, tss,
+                write_section_data(ts, tss,
                                    p, len, 0);
                 /* check whether filter has been closed */
                 if (!ts->pids[pid])
@@ -1782,12 +1781,12 @@ static int handle_packet(MpegTSContext *ts, const uint8_t *packet)
             }
             p += len;
             if (p < p_end) {
-                write_section_data(s, tss,
+                write_section_data(ts, tss,
                                    p, p_end - p, 1);
             }
         } else {
             if (cc_ok) {
-                write_section_data(s, tss,
+                write_section_data(ts, tss,
                                    p, p_end - p, 0);
             }
         }