Regarding the other posts, I don't subscribe to Amazon etc. (yet) so can't test it for myself but given the success that I had the very first (and now routine) time with Netflix decoding from DD+ to DD5.1 on the optical, once I set the audio settings off of Auto and to max out at DD5.1, I suspect strongly that it will work to decode any DD+ source material (why wouldn't it?) and also since one can select the output capabilities of the optical and HDMI audio outputs separately, I suspect that it will decode the signal over HDMI as well (exactly as the Roku rep said it should do earlier in this thread).
well I have had this receiver for about 8 years (it is an Arcam AVR350; so a very capable high end piece). And the optical out from the Roku Ultra is directly connected into one of the optical inputs of the Arcam. I have other optical and coax connections into that same Arcam from other sources, including my Oppo BDP-83, my DirectTV Genie (which switches all of the time between DD5.1 and PLII of course for commercials vs other broadcast source material), and using the Oppo as CD player, to name a few, and also the output of my Pioneer plasma (which passes out optical audio from broadcast TV that it receives other the air, and thus switches its audio output over its optical routinely between PLII and DD depending on the program/commercial/etc.) also directly connected into the Arcam, and have never heard this clicking once. It happens every time, reproducibly, and pretty loudly at normal volume setting, to the point that I worried that it might even damage the speakers (but doesn't seem to have done it yet at least) with the Roku Ultra whenever I select a Netflix movie and start to play it.
So I do think that it is likely at the hands of the Roku and thus warrants investigation by Roku to see for themselves and if so fix it (and let us know or pass on a software/firmware update it that is what it takes to fix it).
I can confirm that the Ultra DOES decode DD+ from Netflix through the optical port and outputs DD5.1. I just bought a new ultra for exactly this feature and tested it out; c..........................
I am hoping to isolate the issues soon. My receiver can not strip audio from HDMI, it only acts as a pure HDMI pass through, so I can not test whether the issue is isolated to over optical or also through HDMI; someone else will have to do that.
I will also have to subscribe or find some other non-Netflix stream to test whether it is intrinsic to any DD+ source because that is all that I have now available (and all that I really initially cared about); but if anyone wants to suggest another free DD+ program to try it out on, I can do that. I will also switch optical cables as well in the next day or two.