Have a Roamio connected to a Samsung SmartTV. Even though set for Dolby, sound output from TV to AV received is only 2 channel. Seems like Roamio doesn't pass Dolby via HDMI. Other video/audio direct from TV (Netflix, etc) work correctly for Dolby 5.1. Do I need a separate optical from Roamio to get Dolby 5.1?