convert 8mm-avi of 19 fps to 24 fps

Hi everyone,
i have a digitalized 8 mm scan, which is basically a bmp-sequence dumped in an avi-container.
But by accident it is set to 19 fps. Does anyone know what is the best way to speed it up to 24 fps and not lose to much quality?
Each time when i try to convert it to 24, the movie has the same duration, but plays it with 24fps, so it's still a bit in slow motion.
Thanks!