[FFmpeg-devel] [PATCH] avformat/mpegts: respect program number when merging streams

[Marton Balint]

merge_pmt_versions was not usable if multiple programs were present because
when it was searching for candidate streams it did not make sure that the PMT was
of the same program. This caused the streams of all programs to get merged into
a single (garbled) program.

This patch makes sure that the program number (service ID) is also matching
with the old streams when parsing the PMT making the feature useful for multi
program streams.

This change might cause issues for single program streams if the program number
changes as well, but I think it is acceptable because the goal of the option is
to make the parsing resilient to PID changes, and that is still working as
expected.

Signed-off-by: Marton Balint <cus at passwd.hu>
---
 libavformat/mpegts.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index 8a84e5cc19..47d8d5f877 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -2130,7 +2130,7 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
     return 0;
 }
 
-static AVStream *find_matching_stream(MpegTSContext *ts, int pid,
+static AVStream *find_matching_stream(MpegTSContext *ts, int pid, unsigned int programid,
                                       int stream_identifier, int pmt_stream_idx)
 {
     AVFormatContext *s = ts->stream;
@@ -2139,6 +2139,8 @@ static AVStream *find_matching_stream(MpegTSContext *ts, int pid,
 
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];
+        if (st->program_num != programid)
+            continue;
         if (stream_identifier != -1) { /* match based on "stream identifier descriptor" if present */
             if (st->stream_identifier == stream_identifier+1) {
                 found = st;
@@ -2309,7 +2311,7 @@ static void pmt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
         if (ts->pids[pid] && ts->pids[pid]->type == MPEGTS_PES) {
             pes = ts->pids[pid]->u.pes_filter.opaque;
             if (ts->merge_pmt_versions && !pes->st) {
-                st = find_matching_stream(ts, pid, stream_identifier, i);
+                st = find_matching_stream(ts, pid, h->id, stream_identifier, i);
                 if (st) {
                     pes->st = st;
                     pes->stream_type = stream_type;
@@ -2331,7 +2333,7 @@ static void pmt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
                 mpegts_close_filter(ts, ts->pids[pid]); // wrongly added sdt filter probably
             pes = add_pes_stream(ts, pid, pcr_pid);
             if (ts->merge_pmt_versions && pes && !pes->st) {
-                st = find_matching_stream(ts, pid, stream_identifier, i);
+                st = find_matching_stream(ts, pid, h->id, stream_identifier, i);
                 if (st) {
                     pes->st = st;
                     pes->stream_type = stream_type;
@@ -2353,7 +2355,7 @@ static void pmt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
                 st = ts->stream->streams[idx];
             }
             if (ts->merge_pmt_versions && !st) {
-                st = find_matching_stream(ts, pid, stream_identifier, i);
+                st = find_matching_stream(ts, pid, h->id, stream_identifier, i);
             }
             if (!st) {
                 st = avformat_new_stream(ts->stream, NULL);
-- 
2.16.4