In order to submit, you need to hold the rights to all the images and sounds included in your work unless you are absolutely sure they are in the public domain. If you used anything created by others, including pictures, models, sound effects or music, you need to have written permission by the copyright owner of that picture, model, sound effect or music to use the copyrighted material. This permission should cover both the screening of the work and the subsequent publication on DVD. Writing a statement yourself that you have permission to use copyrighted material is not sufficient. We also do not require you to give us any exclusive rights.
Wikipedia states: “A creative work is said to be in the public domain if there are no laws which restrict its use by the public at large” [link]. Images and sounds enter the public domain a certain number of years after either their creation or the death of their creator. Be aware, however, that there are exceptions. For instance: Mickey Mouse would have been in the Public Domain by now had his release not been blocked.
Government-created works are usually in the public domain; for example, you can freely use NASA photographs.
Purchasing a song on iTunes or on CD does not give you the rights to use it in your work.
Royalty-free is not the same as free from copyright. Only if you yourself purchase royalty-free sounds and images are you free to use them in your work.
Though it is true that for educational purposes the copyright laws make exemptions under fair use, this does not apply to student projects that are displayed outside the educational setting—such as at a festival like MetroCAF.