- Moment delta_t = now_mom - last_mom_ ;
- last_mom_ += delta_t;
- track_l_->add (delta_t, l);
+ Moment delta_t = now_mom - last_mom_;
+ last_mom_ = now_mom;
+
+ /*
+ this is not correct, but at least it doesn't crash when you
+ start with graces
+ */
+ if (delta_t < Moment (0))
+ delta_t = Moment (0);
+
+ track_->add (delta_t, l);