if (i->second != AV_NOPTS_VALUE) {
double const pts = i->second * av_q2d (_format_context->streams[_video_stream.get()]->time_base) + _pts_offset.seconds ();
if (i->second != AV_NOPTS_VALUE) {
double const pts = i->second * av_q2d (_format_context->streams[_video_stream.get()]->time_base) + _pts_offset.seconds ();