Is there no-where a complete list of public domain music?

My chorus is making a video for our personal use and want to be sure the songs are legal. Though our chorus is for-profit (the director's livelihood) the video will not be sold for profit, but only to over production costs.

Maybe we don't even need to worry?

Any leads orinformation would be greatly appreciated. We'd like to avoid having to hire a lawyer for a complete workup of songs.

Holly Whiteside Voices from the Heart Portsmouth, NH