Since the last update the official Stadia app (downloaded via Google Play Store) on my Sony XH90 / X900H Android TV is finally running smooth and is able to use 4K and HDR.
But still I don't get 5.1 sound. It always shows that 5.1 sound is not supported.
All other apps on my TV (Netflix, Prime, Disney+...) are able to output 5.1 sound to my AVR. Even when I connect my CCU to the TV i can get 5.1 sound.
Anyone else with this problem? Anything I can do to get 5.1 sound?
Hello @Broncanius
Stadia 5.1 channel audio is encoded using a low-latency format that must be decoded into PCM by the TV or CCU. The challenge then is getting 5.1 channel PCM into a surround sound system. If the CCU is plugged directly into a receiver (for example), that works fine, since the primary HDMI audio channel can carry 5.1 channels of PCM. But, if the CCU is plugged into a TV (or if the TV is receiving the Stadia stream itself and decoding it), then there are really only two ways to get that audio into the receiver. One is the "Audio Return Channel" (ARC), which is through an HDMI connection, but in the reverse direction from TV to receiver (from the receiver's perspective, the audio is coming in through its HDMI "out" connector). But, regular ARC can't carry 5.1 channels of PCM audio – it can only carry 5.1 channels of compressed audio (and only in a standard format like Dolby Digital). There is a newer "enhanced" ARC (eARC) that can carry 5.1 channels of PCM audio, but it looks like a lot of TVs and receivers don't support it yet (or even more confusingly, only some of their HDMI ports support it while others don't).
The other method is very similar – using an S/PDIF connection (either optical or coaxial RCA connector). But, that uses the exact same format as ARC, and is subject to the same limitations.
It's also possible the Stadia app for your TV just doesn't support decoding 5.1 channel Stadia audio in the first place (but even if it did, it might still be subject to the limitations of ARC or S/PDIF, etc.).
Other streaming services can use standard high-latency formats like Dolby Digital all the way through, so they don't have these issues (but they don't have the low-latency requirements that Stadia does).
So, if you have a surround sound receiver or sound bar, you may be able to get 5.1 sound by connecting a CCU to one of its inputs so you aren't trying to rely on ARC from the TV. That may have some impacts on the video processing delay through the receiver, though.
Thanks for your elaborated explanation.
My TV supports eARC and is connected via HDMI to my Denon AVC-X3700H wich is a AVR from the newest generation.
Also the Kodi app and VLC Player app on the TV seem to be able to passthrough audio signals directly to the AVR, so I think technically the TV should be able to passthrough the PCM via eARC.
It just seems like the app does not recognize the TV device that is able to receive 5.1 data. This maybe even Sony's fault, as the firmware of the X90H / X900H models is mostly crap.
Is there any way to force the app to receive and output 5.1 sound?.
So, it looks like that receiver supports eARC, but only through the "monitor 1" HDMI output. I would check to make sure you're using that one. The Kodi and VLC player apps may be sending stereo PCM over ARC, or sending 5.1 channel Dolby Digital or DTS over ARC as well. But, if you're positive they are sending 5.1 channel PCM over eARC, then it may just be that the Stadia app for that TV doesn't support it, and when the TV negotiates with the CCU, it may not be telling the CCU it can accept 5.1 channel PCM over HDMI. This stuff is just super-complicated. I have heard rumors that Google is working on improvements in this area, but there's only so much they can do given all of the constraints and pieces they don't control. Still, I'm hoping we'll see some improvements at some point.
In the mean time, I would connect the CCU to one of the HDMI inputs on that receiver – you should get 5.1 channel audio if you do that (I believe it's working on my Denon AVR-X1600H).
Yes, I have connected my CCU to my AVR and 5.1 sound works fine there. But it would be nice to be able to use the Stadia app on my livingroom TV and use the CCU for example for my bedroom TV.
Also I have the feeling (but I can't really proove it), that the CCU has slight more delay (or lag?) than using Stadia on my PC (in Chrome, Windows 10) and also more delay than the app on my TV.
The delay seems not to be a problem of the AVR, as it also occours when connecting my CCU directly to the TV. Also my PS4 does not show any delay and is also connected to the AVR.
My CCU is connected via ethnernet-poweradaptor to the same network my PC or TV is connected to.