So what does compliant mean? Artists are getting paid?
Music licensing is kind of complicated in the U.S., partly driven by historical reasons. Copyright doesn't just restrict copying, it also restricts broadcast or public performance of copyrighted work as well. Services like spotify allow users to choose what they want to listen to on demand, which requires a different (and more expensive) sort of licensing than, say, a normal radio station needs, which is a different sort of license than, say, a band covering a song needs. Most people aren't aware that plain old terrestrial radio stations (or satellite radio stations for that matter) need to pay license fees too, just like Spotify.
For historical reasons the "radio-type" license is much cheaper than the "play what you want" type license. To qualify for the radio streaming license you need a service that's less interactive and more varied (users are limited in their ability to choose what they hear and, generally, whole albums aren't getting played). There are a few online services that have tried to capitalize on the comparative cheapness of the radio-type licenses (although the fees are still significant, just not as high as what play on demand services pay).
To be clear, I don't know if JRiver is using the radio-type licensing, or if they negotiated some other kind of license (I don't work for JRiver, obviously), but the structure of the service suggests something akin to the radio license. When I worked in radio, we payed an annual fee to ASCAP (the rights-holder for most songwriters publishing in America), and we also had to log and report what we actually played. ASCAP aggregated the reported plays and the fees from all licensed stations, and then doled out the royalties to the artists based on play share (after taking their cut).
