for (size_t row = currently_playing_idx; row < clips.size(); ++row) {
const Clip &clip = clips[row].clip;
double clip_length = double(clip.pts_out - clip.pts_in) / TIMEBASE / clip.speed;
for (size_t row = currently_playing_idx; row < clips.size(); ++row) {
const Clip &clip = clips[row].clip;
double clip_length = double(clip.pts_out - clip.pts_in) / TIMEBASE / clip.speed;