Streaming music service Rdio today announced that it will upgrade its entire library of music to AAC audio files, which offer a higher quality of sound than MP3. The move marks the first time Rdio is giving users more control over the sound quality while listening to songs on mobile devices as well as desktops and home audio systems. In this case, Rdio is giving users four different options for sound quality, which can be adjusted to fit your preference based on your device and Internet connection.