demo playback position interpolation/lag compensation

the movie and screenshot section was appearently not the correct place for my problem, so here again:

i am recording a demo to make a video out of it afterwards. because there is a lot happening, it is laggy as hell. unfortunately, it seems that the position of every entity is only sampled at every rendered frame. so if the framerate drops to 5 fps while recording the demo, and then it is played back with a fixed framerate of 30fps, the position of every entity is updated at every 30/5=6th frame. the result is visualised in the following gif:

http://www.wduwant.com/index_uploads/uploads/18ac5c1295a3.gif

you can see that the animations of the npc is updated every frame (the same for water etc.) but the position hops from frame to frame of the original framerate. is there any posibility to prevent this? either at demo recording time or at least as position interpolation during playback?

parameters like cl_interp dont seem to resolve this issue.