The jitter that your seeing is due to the conversion from 24hz to 60fps. Typically what most regular software will do is take the 24 frames and blend the frame before and after to generate a new frame, this brings you up to 48fps. The difficulty is when you need to generate the other 12fps, how you do it, and when you place them. Depending on how good the software is, and how fast your computer is, the additional 12 frames a second can go unnoticed, but if you do a bad job you'll get a stutter.
I find using the built in hardware decoders helps the most (newer cards), while the older ones need to brute force it with cpu time.