Rdio is to upgrade its entire music library to the higher quality AAC audio format.

The move means that the streaming service’s users will have four different sound quality options, which they can choose based on their device and internet connection.

At one end, 64 kbps is the most data-efficient format while 192 kbps delivers greater sound quality at the top. Rdio Unlimited subscribers meanwhile have the option of going to 320 kbps.

Rdio has a catalogue of 30 million ...