Best way to output surround sound over toslink?
#1
I've recently bought a soundbar for the bedroom and have a Raspberry Pi 4 setup already for video/music playback running LibreElec.

The Panasonic TV has an optical output, but I don't think it passes through DTS/AC3 - it works fine for PCM to sound bar but that leaves me with just 2 channels.

I have to hand a Topping D10 USB>SPDIF convertor, this also decodes to PCM OK for music playback. But, when I select passthrough option in Kodi for AC3/DTS it produces a harsh scrambled noise upon playback. Also, the "PCM" status on the soundbar does not change.

What devices are recommended to acheive reliable DTS/AC3 passthrough? Toslink connectivity would be ideal, but the soundbar also has analog inputs so a USB 5.1 soundcard may also work as a last resort...?

Any advice would be much appreciated.

Thanks
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#2
Google Hifiberry.

For some reason it didn't let me post link.
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#3
(2021-06-30, 09:54)daws0n Wrote: I've recently bought a soundbar for the bedroom and have a Raspberry Pi 4 setup already for video/music playback running LibreElec.

The Panasonic TV has an optical output, but I don't think it passes through DTS/AC3 - it works fine for PCM to sound bar but that leaves me with just 2 channels.

I have to hand a Topping D10 USB>SPDIF convertor, this also decodes to PCM OK for music playback. But, when I select passthrough option in Kodi for AC3/DTS it produces a harsh scrambled noise upon playback. Also, the "PCM" status on the soundbar does not change.

What devices are recommended to acheive reliable DTS/AC3 passthrough? Toslink connectivity would be ideal, but the soundbar also has analog inputs so a USB 5.1 soundcard may also work as a last resort...?

Any advice would be much appreciated.

Thanks

I have several of these and I use them daily.

https://www.amazon.com/iArkPower-Optical...B01K7BZ1XC

They are much cheaper than dedicated audio extractor’s I was looking at and it also allows me To switch HDMI inputs. Are use it to output the sound to coaxial because I run 24bit flac files. It works extremely well I am very happy with the audio quality. I have one set up where I use all three audio outputs because depending on what my source is, I use a different receiver. So it’s very helpful to have one channel extract to LR stereo, one goes to Co-axial and the other to optical. So by switching the HDMI I am automatically switching the audio processing. This HDMI switcher also allows for 2ch,7.1,pass,spdif, and ARC on its little remote.

Note: there are so many different “brands” of these switches most of which of them are some sort of Chinese generic. So I usually go with Monoprice or Ugreen, or the one that I linked to, because I’ve had positive experiences with their other audio products.
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#4
There is a difference between 2 channel and 8 channel optical interfaces. However - 

See also:  https://forum.kodi.tv/showthread.php?tid=363587 and follow the HDMI config info on the RasPi site that's linked there.  The different HDMI versions/standards SHOULD all include multichannel digital audio

I also have a Panasonic display - I take optical out into my 5.1 amp (RasPi4 HDMI out into display), but for some reason the amp doesn't see 5.1.  I suspect the display's optical out is TOSLink, which is a 2 channel interface, but I haven't made the config.txt change to kodi to test it out. 
It may be best to make the chain HDMI completely - Pi/kodi -> receiver/ampifier -> display
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#5
Thanks for the help everyone.

I got everything working fine using a Douk Audio D2 USB > SPDIF convertor. Oddly enough it utilises the same XMOS u208 chipset as the Topping D10, but passes DTS and AC3 straight through without issue.
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