On this case the recommendation will be to use a different video player, like VLC, and make sure that the content that you are trying to reproduce on 5.1 or Dolby does have this audio string.
Another recommendation will be to connect the optical cable from your laptop direcly at the audio optical receiver and see if you get a different audio option at your TV.
@Steve In order to get 5.1 audio, you'll need to pass your HDMI cable connected through your stereo receiver. That is, the MainStage will connect to an HDMI input and the TV to the receiver's HDMI output. You'll get 5.1 this way, provided that the content you're playing supports it.
Intel WiDi - Applications Engineer
I have connected the optical out on MainStage to the optical in on my 5.1 system with the same result. When I go HDMI -> TV there is an optical out on the TV and my TV has the functionality to take the audio stream from the HDMI signal and put it over it's optical out. This is how I get 5.1 on my PS3 and XBOX without issue.
On the Video player front, VLC is the player I've been testing with because it can properly take over an audio device and switch it to 5.1 (The WIDI audio device allows applications to take full control) and it still only has the Stereo option.
Is there a requirement to use a dual-band router with MainStage in order to get WiDi to stream in full 1080P/5.1? I can only get 720P (My TV can accept HDMI resolutions up to 1080p)
Lately I've been having the same issue with the sound. I thought it was something related with the player since all the connections met the requirements (all HDMI, latest firmware for WiDi adapter, reciever ok), so I tried a different one...Obviously none of this worked. So I've decided to start all over, one step at the time. After trying a couple of things, it was the turn to "reset" the WiDi Adapter by pressing the reset button for more than 8 seconds. After that I started the WiDi Software, made the basic configuration and started the player. Now it's working "Ok" again.
Hope you can find this info usefull!
P.S.: WiDi Adapter: D-Link DHD-131
Reciever: Onkyo TX-NR809
Notebook: HP Envy 14 2050SE