I have read that there was a recent firmware update to the VIA apps, which among other things enabled Dolby 5.1 audio in the VIA Netflix app. I'm not sure if my M470NV has been updated yet (still looking for info on how to tell for my model). I do know that in the HDTV settings I switched the Digital Output from "PCM" to "Dolby Digital". However, when streaming Netflix content my Onkyo HT receiver still reports that the signal coming from the TV's optical audio out port is PCM, not Dolby. The receiver is doing its own "pseudo" surround sound (Dolby IIz) so it seems that I'm still getting a stereo audio stream from Netflix through my TV.
I'm wondering, do only certain titles in Netflix have surround sound encoding? Or do I just need to wait for Netflix/Vizio to update my TV?