> How do you synch the two, and in the case of dropped frames, > how do you tell
> what which frames to drop? This is hard because you don't > really have a
> sense of "movie time", you just have absolute time rolling by.

The time for "steps" was never an absolute sense of time, just an approximate reference to how much "slack" the system would assure before giving the next one.  Accordingly, if you have many more morphs than the frame rate can handle, the only way to assure a consistent "real-time" feel is precisely to keep track of absolute time since the last step, compute the frames to drop, if any at each step, and display accordingly.  In the "bad old days" of game design on REAL SLOW MACHINES, that is precisely how we did things.

In practice, I haven't found this to be so hard -- provided you can define the time-state as a parameter of time, and compute the display corresponding to that state accordingly.  Where "movie time" is sped up or slowed down, we simply added a scaling factor to the absolute time parameter.

Am I missing something?