You must have the rights to any images, video clips, or music files you
upload. Animoto absolutely respects the rights of copyright holders for
images and music. Our policy is to respond to any notices of alleged
infringement that comply with the Digital Millennium Copyright Act
(DMCA), which may include removing the content. Animoto reserves
the right to terminate your account and video creations in accordance
with our Terms of Service.

If you're curious about music licensing, we found this guide to music licensing to be extremely helpful.