Getting DD sound

Anyone can help?

OK, I'm not sure what you're asking.

You wouldn't have a "line in" showing up unless you had something plugged into a "line in", which you don't even have in your setup.

Are you sure that your PC, which I think is connected to your TV by an HDMI cable is putting out a Dolby Digital Signal? And if so, are you certain that your TV is set to directly send a Dolby Digital signal out through the optical out connection?

What happens when you play a movie on your TV? Does it show up in the Sonos App correctly?

I think that you need to check the audio settings on your PC, to ensure that it is sending that Dolby Digital signal out through the HDMI.

I'll agree with Airgetlam... I'm pretty sure that most PCs won't send DD audio out unless it's being passed directly through from a source. Most likely whatever program you're playing the video through is decoding the DD from the file and sending it to Windows' sound drivers as PCM. Sonos doesn't support PCM 5.1, so it downconverts it to stereo.

You would need to find out if...
1. Your video card is capable of outputting Dolby Digital audio through the HDMI connection (this might vary among cards)
2. Your program for playing the video is capable of sending the Dolby Digital audio from the file directly to the HDMI output, skipping the Windows sound system and PCM conversion

I am not sure if the PC is sending DD through HDMI (in that regards, does changing a HDMI cable/plug play any role?). How can I check that out for sure, where can I see the settings?

I am certain that the TV sends DD because it was confirmed by someone with the same TV model.

I am not sure about playing a movie on your TV. On which media? I play all my movies from the PC.

My videocard is MSI GeForce GTX 960 GAMING 2G 2GB GDDR5. Do you know does it pass DD on via HDMI? I can't find that info anywhere.

I can use whichever video player you guys think should work. I am mostly using VLC though.

Rainalkar:
I'm going through a very similar issue. I'm also using a MSI video card, but in my case a GeForce GT710.

Here's what I noticed looking at the Windows 7 sound settings on my HTPC. If I have the audio set to go out to the TV over HDMI I notice that the sound settings in Windows shows only 2 channels. I've opened a support ticket with MSI asking them to confirm which audio formats they support over HDMI for the GT710. My TV is an LG OLED65B6P and I can confirm that it supports DD 5.1 over it's optical out port.

So, I've dropped the HDMI option and am now trying to get 5.1 surround directly over the PC's optical out port. But surprisingly the Playbar still only sees stereo when getting the audio stream from the PC's port (Realtek chipset on the motherboard).

It has me stumped as I'm 100% that the movie is encoded in AC3 at 48KHz. This should work! In fact if I reconnect my old Yamaha AVR to the optical cable I do get 5.1 surround. So, IMHO there's something not right with the way the Playbar detects the AC3 stream.

Rainalkar:
I've contacted MSI support. They confirm that NONE of their video cards support Dolby Digital over HDMI.
Ack!
Now the question is do any of the video card manufacturers support DD?

Tom12 lists a few in his last post in this thread:

https://en.community.sonos.com/home-theater-228993/cant-get-51-audio-only-stereo-from-htpc-6761648

I have just replaced the MSI nVidia GT-710 with a Zotac nVidia GTX-1050 and I can now get Dolby Digital 5.1 over HDMI. So, it's true that some video cards will pass nothing more than stereo over HDMI. What's strange is after I installed the new GTX-1050 I went to the Windows 7 sound applet and checked the HDMI output it still showed just 2 channel audio. I was thinking, oh-oh. But then when I fired up KODI and watched a movie, ta-da - 5.1 surround (confirmed by the Sonos app)!
So, it cost me $100 for the new card to get DD 5.1, but I now have a video card that'll do 4K and supports HDMI 2.0b.

Well, the cards that don't support DD may well still support 5.1... but it's likely PCM 5.1. Sonos only understands PCM as stereo (which is unfortunate).