+ if( !tstmp ) {
+ if( st->nb_index_entries > 0 ) tstmp = st->index_entries[0].timestamp;
+ else if( st->start_time != AV_NOPTS_VALUE ) tstmp = st->start_time;
+ else if( st->first_dts != AV_NOPTS_VALUE ) tstmp = st->first_dts;
+ else tstmp = INT64_MIN+1;
+ }
+ else if( nudge != AV_NOPTS_VALUE ) tstmp += nudge;