+static int update_wrap_reference(AVFormatContext *s, AVStream *st, int stream_index, AVPacket *pkt)
+{
+ int64_t ref = pkt->dts;
+ int i, pts_wrap_behavior;
+ int64_t pts_wrap_reference;
+ AVProgram *first_program;
+
+ if (ref == AV_NOPTS_VALUE)
+ ref = pkt->pts;
+ if (st->pts_wrap_reference != AV_NOPTS_VALUE || st->pts_wrap_bits >= 63 || ref == AV_NOPTS_VALUE || !s->correct_ts_overflow)
+ return 0;
+ ref &= (1LL<<st->pts_wrap_bits)-1;
+
+ // reference time stamp should be 60 s before first time stamp
+ pts_wrap_reference = ref - av_rescale(60, st->time_base.den, st->time_base.num);
+ // if first time stamp is not more than 1/8 and 60s before the wrap point, subtract rather than add wrap offset
+ pts_wrap_behavior = (ref < (1LL<<st->pts_wrap_bits) - (1LL<<st->pts_wrap_bits-3)) ||
+ (ref < (1LL<<st->pts_wrap_bits) - av_rescale(60, st->time_base.den, st->time_base.num)) ?
+ AV_PTS_WRAP_ADD_OFFSET : AV_PTS_WRAP_SUB_OFFSET;
+
+ first_program = av_find_program_from_stream(s, NULL, stream_index);
+
+ if (!first_program) {
+ int default_stream_index = av_find_default_stream_index(s);
+ if (s->streams[default_stream_index]->pts_wrap_reference == AV_NOPTS_VALUE) {
+ for (i=0; i<s->nb_streams; i++) {
+ s->streams[i]->pts_wrap_reference = pts_wrap_reference;
+ s->streams[i]->pts_wrap_behavior = pts_wrap_behavior;
+ }
+ }
+ else {
+ st->pts_wrap_reference = s->streams[default_stream_index]->pts_wrap_reference;
+ st->pts_wrap_behavior = s->streams[default_stream_index]->pts_wrap_behavior;
+ }
+ }
+ else {
+ AVProgram *program = first_program;
+ while (program) {
+ if (program->pts_wrap_reference != AV_NOPTS_VALUE) {
+ pts_wrap_reference = program->pts_wrap_reference;
+ pts_wrap_behavior = program->pts_wrap_behavior;
+ break;
+ }
+ program = av_find_program_from_stream(s, program, stream_index);
+ }
+
+ // update every program with differing pts_wrap_reference
+ program = first_program;
+ while(program) {
+ if (program->pts_wrap_reference != pts_wrap_reference) {
+ for (i=0; i<program->nb_stream_indexes; i++) {
+ s->streams[program->stream_index[i]]->pts_wrap_reference = pts_wrap_reference;
+ s->streams[program->stream_index[i]]->pts_wrap_behavior = pts_wrap_behavior;
+ }
+
+ program->pts_wrap_reference = pts_wrap_reference;
+ program->pts_wrap_behavior = pts_wrap_behavior;
+ }
+ program = av_find_program_from_stream(s, program, stream_index);
+ }
+ }
+ return 1;
+}
+