Any ways to use a video as audio for iPhone?

I like to make music & I recorded a video of a piece I really like. I've spent all day trying to find an app that lets me use my video as audio (to where the video won't be shown) & I can put a picture up. I'm not good at explaining things but basically I want an app that works a lot like Windows Live Movie Maker. Editing on there I just pick a picture I like & add my recording to it. I've tried to find something that'll convert a video to an mp3, or something that can store it in my voice memos folder.
If anyone knows anything please let me know.

Do you want to try with Freemake? It's a good freeware that can do many things about convert.