Media recognition specialist Gracenote thinks Pandora (S P) and Apple’s (S AAPL) iRadio could use some competition, which is why the company will release a new API next month that will enable any company to launch a personalized radio service.

Gracenote’s new API, dubbed Rhythm, can be used to build radio offerings that start a customized stream based on an artist, a song, a genre or even a mood. Listeners will be able to like or skip songs, much like on Pandora. And just like the leader in online radio, Rhythm will be based on online radio rules specified in the Digital Millennium Copyright Act (DMCA), meaning that anyone using Rhythm to power an online radio offering won’t have to strike individual licensing deals with record labels.

By offering this kind of music intelligence solution for radio services, Gracenote is competing more squarely with the Echonest, whose music recommendation…