NEED HELP FOR SUBMITTING TO FILM FESTIVAL

Hello, I’m days away from needing to submit a personal short film to a film festival and am struggling to complete some final details.

I need permission documents for some songs I used but am a little lost. 2 of the songs I used are by an artist called ‘Enrico Caruso’. It says online that all his music is public domain in the US but also more specially in Australia, where I am.

a. Does that mean I can use his music freely? b. Do I need any documents for submission ?

I also used a song I found on Audio Network, which is a service to download copyright-free music. Do I need to provide any documents for using that song ?

Finally, I opened the film with a song from a local rap group that gave me permission in person to use their music. Obviously I need written permission but where do I find a document to send them?

Sorry for the information overload and if you read this all, I appreciate you so much.

Thank you everyone, Noah