We recommend uploading all of your works, as our content management system is intended as a tool for you to keep your entire catalog in one place. It is better to have the song available in your catalog and discoverable to potential licensees. After all, you never know what a customer may want.
To maximize your songs' chances of being synched, we recommend recording and producing to a good standard and it's a good idea to get each song mastered. Also, upload 16 bit, 44.1k WAV or AIF files at a minimum.
Click the link to discover a few tips on what Music Supervisors look for and what not to do.