+ if (s->dts_sync_point >= 0) {
+ int64_t den = avctx->time_base.den * (int64_t)avctx->pkt_timebase.num;
+ if (den > 0) {
+ int64_t num = avctx->time_base.num * (int64_t)avctx->pkt_timebase.den;
+ if (s->dts != AV_NOPTS_VALUE) {
+ // got DTS from the stream, update reference timestamp
+ p->reference_dts = s->dts - av_rescale(s->dts_ref_dts_delta, num, den);
+ } else if (p->reference_dts != AV_NOPTS_VALUE) {
+ // compute DTS based on reference timestamp
+ s->dts = p->reference_dts + av_rescale(s->dts_ref_dts_delta, num, den);
+ }
+
+ if (p->reference_dts != AV_NOPTS_VALUE && s->pts == AV_NOPTS_VALUE)
+ s->pts = s->dts + av_rescale(s->pts_dts_delta, num, den);
+
+ if (s->dts_sync_point > 0)
+ p->reference_dts = s->dts; // new reference
+ }
+ }
+