code: private void updatePlaying(double extrp)
      {
          current += speed * extrp;
  
          // Last frame reached
          if (Double.compare(current, last + FRAME) >= 0)
          {
              // If not reversed, done, else, reverse
              current = last + HALF_FRAME;
              checkStatePlaying();
          }
      }
docs: Update play mode routine.
  
  @param extrp The extrapolation value.