yes - that was done. It plays 7.1 fine either on Direct mode via the smart TV through optical OR if I set the playback mode to something like dolby digital or DTS where it takes the 2 channel and divides it up.
Question - do any of the Roku output formats for audio support Bitstream? This is what Onkyo says it is looking for. I would assume it does but no specific setting labled that.
Your Roku should bitstream Dolby Digital, DD+, and LPCM/AAC. If you are playing local media (ripped DVDs, etc.) it will also bitstream DTS from a MKV container.
So I happen to have two Ultras, same model, same software build. I took my second ultra to test on my Denon receiver - it worked as expected there (making me think it was the Onkyo). I then took this same Ultra that worked on the Denon, plugged it into the same cables connected to the Onkyo - and it also worked as expected. Retested my other Ultra - doesn't work. I'm going to double check the Audio settings but at first check everything was identical (all set to Auto).
The only thing I can thing to do is try to reset the Ultra not working to factor defaults and start over. Any other settings or suggestions to check.
Issue found... It was Volume Leveling. Turned it off and now works as expected.
Ah, I always forget about that. Yes, any audio leveling or some such processing will switch the audio to two channel PCM. I have to remember to ask that question... Glad you found it!