see Rik,now you are doing the same stuff i am,changing the framerate,but to do that you have to IVTC the footage,dont you?because from what i have been doing is this,LD capture,then i run an avisynth script to IVTC the avi clip,then once that is done,then i can run filter chains and crop and re-size to make anamorphic widescreen,then after all that,damn this shit takes a long time LOL,then i encode with CCE SP,or you can just set your avi script up and open it in CCE and do the processing and encoding all at once,this is where the 36+ hours comes in to encode.
but you will probably have to use VDubMod and avisynth for your MPEG.
i really dont think you can take a 29.97fps and just encode to 23.976fps progressive without IVTC first,but i could be wrong,but i think that is why it is jumpy.
DJ