There isn't an app that I'm aware of on the Roku that currently uses DD rather than DD+. The last holdout was HBO, and they switched to DD+ last month.
If your receiver supports it, PCM can use Prologic II, which does a good job of converting 2 channel to 5 channel. By the way, you "tested" using Hulu. Hulu is always in PCM...if your receiver ever said otherwise it was because the device sending the info was not sending correct info (probably because it was not autoconverting; eg Xbox does this because it does not autoconvert like Roku does so Hulu will show Dolby Digital if I set the xbox to that). If you listen to the actual output only 2 speakers will have sound even though your receiver says "5.1". Setting something to DD won't change the actual output anymore than setting your resolution to 1080p changes an SD video to HD. To get actual 5.1 you need Prologic II.
I spent 45 minutes chatting with a roku tech earlier today before reading all of this. She tried to tell me that the reason that I stopped getting DD was because of my AVR. After that, I searched and found this thread, which has helped me understand. I have an ultra 4640X hooked up to an AVR that is compatible with DD and not DD+. It’s hooked up via HDMI. I have 3 questions that I hope you knowledgeable users out there can answer.
1. The loss of DD+ to DD transcoding, is that something that roku is trying to fix?
2. Does the optical connection still do the DD+ to DD change?
3. Can I connect the roku to my AVR using both HDMI and optical?
Thanks to all of you.
Thanks for your input. I think that the first thing I will try is using an optical cable.