I’m having the same issue. 5.1 works fine from other inputs but only 2.0 from CCGTV. 

The fact that Dolby Digital is greyed out on the TV’s options page indicates that one end of that cable thinks this is not possible. As the other HDMI port is happy with DD5.1, looks like the CCGTV is the problematic end of the cable: it is not satisfying the DD5.1 handshake either because it cannot, or the source signal doesn’t contain DD5.1 content.

Thank you for your response. I went back to check.
As you can see below. The Chromecast states correctly that only DD is supported and is selected.
The source apps Netflix and Disney+ support 5.1 content as far is I know.
The TV only shows PCM or DTS Neo.

I am at a loss to get this working.
 

Same problem here. I also have the Sonos Beam in combination with a sub and two ones, I

just tried the Amazon Video App where Surround Audio is working!

Maybe the Disney Plus and the Netflix App does not support Dolby Digital on the new Chromecast? Is there maybe a way to make this working?

I just activated the Dolby Atmos function and surprisingly 5.1 Sound is working in Netflix on all 5.1 content. But as soon Dolby Atmos is available Netflix is not playing the video (as the Beam does not support Atmos I guess).

Seems like a workaround for all 5.1 content where Atmos is not available. Hopefully Netflix will release a fix soon.

@MagnusST Are you talking about the apps on your TV or via Chromecast? On my old TV I could never get surround to work from the Chromecast (not using it on the new TV).

From the Chromecast ;)

@MagnusST  Thanks for the suggestion, but for me it did not work. Stereo PCM in all scenario's and apps. I returned the Chromecast. Maybe I will try a Mi Box S.

I use an Nvidia Shield. Works great. Only thing is the Prime app does not do DD. I use my TV for apps though.

Well, I have two TVs, the Samsung and TCL. When I connected the Chromecast with Google TV to the Samsung, I got the same result as the OP. Just switched the Chromecast to TCL and got 5.1 DD+ and Atmos passing to Sonos Arc. 

@kide For future reference, maybe it’s a good idea to publish the model numbers of your TV’s here.

Try installing the Kodi Android app on your Chromecast with Google TV and set the Kodi audio settings to Passtrough. Playing 5.1 DD video through Kodi works :)

They do, but only in DD+, not DD, and this seems to be the problem. Since the CCwGTV detected your device to be incompatible with DD+ it falls back to PCM Stereo. It would probably fall back to DD first if this was offered by the apps but it isn’t.

You can verify this by forcing DD+ in the CCwGTV settings list for unsupported formats, which results in the “5.1” logo appearing in the Netflix movie/series preview screen next to the 4K logo (but obviously no sound if your hardware doesn’t support it.) Whereas if you only activate DD, the 5.1 logo disappears entirely, indicating that the app has no DD fallback, only stereo.

Now what the CCwGTV should do is transcode the DD+ to DD if it detects DD+ incompatible but DD compatible hardware, like the Shield, Fire TV 4K and Apple TV 4K all do according to my research. Glaring oversight on Google’s part, every forum is ripe with surround sound compatibility issues around the CCwGTV as a result.

If this is all correct the piece that confuses me is the Netflix app on my Samsung tv is outputting surround to my old Pioneer AV amp just fine which I expect is the app providing DD rather than my tv transcoding, so not sure why the app on Chromecast can’t do the same. 

I’m pretty certain the Netflix app on your TV downloads the same source material as a Chromecast which is evidently DD+. I can’t imagine Netflix stores duplicates of every sound track in different formats for different devices, but maybe I’m wrong. As far as I can tell, transcoding is a common feature for these kinds of devices, DD+ is backwards compatible after all so it shouldn’t require intensive processing power or anything.

How old is your Samsung TV then? If it’s rather old it would maybe back your theory that the source material is already DD as an old TV could potentially not be able to transcode DD+. Although even then, that could always be added over a firmware update. If it’s a newer model I would say it backs my theory that the TV knows both DD+ and DD but detects that your receiver is only compatible with DD, so it transcodes the DD+ audio track accordingly.

Samsung TV is 2014 or 2015 I think so it possibly knows DD+ (if that is needed, depends how the backwards compatibility works?).
 

From what I’ve read a non-HDMI digital output to receiver will only send DD not DD+ so sounds like the TV can receive DD+ and necessarily output DD without any ‘detection’ of receiver capability happening. Does that mean the barrier is that the  CCwGTV isn’t passing the TV DD+ over HDMI rather than it not transcoding to DD which the TV can handle itself?

Sounds plausible to me as SPDIF (only non-HDMI digital output I can think of) can only do DD anyway, I think the spec calls it PCM 5.1 oder LPCM, so no ‘detection’ necessary as it’s the only surround Format that fits in SPDIF anyway.

Interesting question. I never thought about that as I assumed the TV would simply pass through the digital audio ‘as is’ neverminding what it is and wether it can understand it. And in the case of Netflix on CCwGTV I can somewhat confidently verify by manually enabling and disabling the surround formats that it:

• passes DD+ when DD+ is exclusively enabled. A “5.1” icon appears in the Netflix app. Samsung TV automatically switches to “Digital Audio Out Audio Format: Dolby Digital”  (no + ironically, but I’m certain that it passes through the DD+ as mentioned above. “Dolby Digital” is just the only menu entry that exists, they have no specific DD+ entry) It passes through the DD+ to my only-DD-compatible Soundbar and ...… silence, expectably.
• passes PCM when DD is exclusively enabled. “5.1” icon disappears and TV switches to PCM digital output and I hear stereo on my Soundbar.
• forcing “Dolby Atmos in DD+” is the same as forcing DD+

From that and from this Netflix help article specifically requiring DD+ comes my conclusion that the Netflix source material must be both DD+ for surround and PCM for stereo and the CCwGTV makes no move to make different surround formats “work” by transcoding. It just goes ‘well all your device can do is DD and there is no DD material here, so here’s your PCM stereo” and that’s it. And when you ignore the detection and force DD+ it goes “yup, here comes DD+” and it obviously results in silence when the receiver/soundbar is not compatible.

Now you do make a point when you say if the TV can transcode from the Smart-TV-Netflix-App then it should be able to do the same on the HDMI pass through. I’m just not sure if it’s actually supposed to do that. I’ve been looking in the Samsung TV service menu while writing this but I haven’t found anything about surround sound formats or transcoding unfortunately.