Best method to slightly adjust start and end speed?

I’ve got an image sequence with a fixed frame rate. The frames are generated from a different application which has no fine-tuning of camera controls. I’d like to ever so slightly adjust the start and end of the sequence to gradually ease into and out of this sequence rather than the sudden start/stop, without buggering around too much.

What’s the best way to accomplish this with the VSE or compositing nodes?