Harry Fox re sync licenses:

...You want to include a musical work as part of an audio-visual project (e.g., music video, film, commercial, karaoke, or “CD+G”). The right to include a pre-existing musical work in time-relation with an audio-visual project is typically known as the “synchronization” or “synch” right, and it requires permission from the copyright owner of the musical work. If you are a music distribution company seeking assistance in obtaining and administering synchronization licenses for commercial use or are distributing a video for non-commercial use that includes music you don’t own or control, HFA’s Rumblefish may be able to assist.