I want to make a length of animation run at half the speed. So I would do this:-

If the animation is n frames long, make it 2*n frames long.

for A in poser.Scene().Actors():

. for j = n (-1) 1 :-

. . for P =  each parameter dial in turn of actor A :-

. . . B = all the frame information (value, whether it is a keyframe, spline settings) for frame j of parameter dial P of actor A

. . . delete frame j of parameter dial P of actor A, if it is a keyframe

. . . delete frame 2*j of parameter dial P of actor A, if it is already a keyframe

. . . set frame 2*j of parameter dial P of actor A to the value and keyframe settings of B, if B is a keyframe

Please, has this been done before?