FrameTempo
From Director Online Wiki
the frameTempo is a theoretical value. In practice, the Director Player will normally play back a movie at a rate slower than the frameTempo.
To determine the instantaneous tempo of a movie at any time t, you will need to use a behavior such this:
property pLastMilliseconds property pFrameTempo
on beginSprite pLastMilliseconds = the milliseconds end
on enterFrame tMilliseconds = the milliseconds tTimeElapsed = tMilliseconds - pLastMilliseconds
pFrameTempo = 1000.0 / tTimeElapsed pLastMilliseconds = tMilliseconds end
on getFrameTempo return pFrameTempo end