I just spent the best part of a couple of hours putting together this command so that I could make my own movie to upload to insatgram.

I thought it might be worth sharing, so here it is with a little explanation:
ffmpeg -loop 1 -i image.jpg  -i music.ogg -c:v libx264 -strict -2 -c:a aac -ar 44100 -r 30 -pix_fmt yuv420p -shortest out.mov
Essentially this joins a music file (mono, ogg, 57secs) with a 600x600px jpg image to make an instagram clip. Instagram clips are a maximum of 60sec long. libx264 is H.264 video codec and acc is the audio codec. Audio must be at 44100 Hz and the frame rate 30fps. Don't know if the -pix_fmt option is necessary, but doesn't hurt. -shortest makes the clip run the length of the audio.

If anyone has a simpler solution, I would be glad to hear it