Does anyone know why a streaming service would output only stereo from a Roku device but output surround sound from an iOS device (iPhone) screencast (via AirPlay) to a TV (connected to a Dolby Digital-capable soundbar)? The streaming service in question is Kanopy. The issue is not the Roku device itself since other streaming services on the Roku can output 5.1 surround sound. I tested the same movie on Kanopy from both the Roku and the iPhone. My TV is an LG BX OLED which has no native Kanopy app.