Ive been looking for an app like this since I first got my iPhone three years ago. It slows down or speeds up a video with fade in or fade out effects, that is the video slowly slows down or slowly speeds up. Just set the cue in and cue out points. Its simple and intuitive and it works just fine. And its free! Can you believe it?
kc135 about Slow Fast Slow - Control the Speed of Your Videos, v2.2