for kf_time in self.keyframes.iter() {
let pts = tsearch.map_time(*kf_time - 1, &self.time_to_sample);
let time = NATimeInfo::ts_to_time(pts, 1000, self.tb_num, self.tb_den);
for kf_time in self.keyframes.iter() {
let pts = tsearch.map_time(*kf_time - 1, &self.time_to_sample);
let time = NATimeInfo::ts_to_time(pts, 1000, self.tb_num, self.tb_den);