This paper describes a comprehensive study on the sound quality of the Opus codec for stereo, surround and immersive audio formats for music and cinematic content. We conducted three listening tests on Opus encoded stereo, 5.1 and 7.1.4 test samples taken from music, cinematic and EBU files encoded at bit rates of 32, 48 and 64 kbps per channel. Preliminary results indicate that a bit rate of 64 kbps per channel or higher is required for stereo, but 48 kbps per channel may be sufficient for surround and immersive audio formats.
