Screen-capturing Flash animation

Hi, I’m using screen captrue software (camtasia studio 6) to capture a video of my flash animation. But when I capture it, the aniamtion is jerky.
My flash animation is set to 30fps and looks great when played, but not when I play back the captured movie.

I have experimented with a few other codecs, including the Techsmith default, cinepak and microsoft video but they are all the same.

Could someone recommend to me a good codec to use that will capture my animation better? Or point me to a good tutorial?