Deezer is a web-based music streaming service. It allows users to listen to music content from record labels including EMI, Sony, Universal Music Group, and Warner Music Group on various devices online or offline.he service will be available to worldwide to Sonos users of Deezer only. It should be noted that Deezer Elite High-Resolution Audio is lossless CD quality (16bit/44.1 kHz) and not Hi-Res or High-resolution audio.