How to create movie from images *with transitions between images*

There seem to be lots of iOS developers who want to create a movie from a set of images, b开发者_开发技巧ut I would like to include a transition between the images -- just a quick opacity ramp from one image to the next.

I've been googling and studying the docs, and can't see how this can be done with AVAssetWriter. It looks like I need to use AVMutableComposition to get the transitions.

Question: Is this correct? Or am I missing something with AVAssetWriter?

TIA: John

I've never tried, but how about Core Animation to do the transition (or any kind of animation)? You setup the animation, move the timeline, grab a "screenshot" of the animation and write it on the movie. Repeat it until the animation is completed.