Hi all, I think I found a small problem with Coreelec 9.0.3.
Because my AV receiver (Yamaha RX-V675) doesn’t support HDR I connected my Odroid N2 to it with optical spdif and added a direct HDMI from the odroid to the TV. This works well, with both audio out and audio bypass set to spdif in coreelec I get DD/DTS 5.1 and lpcm on my amp and no audio on HDMI - just as I wanted.
Unfortunately this doesn’t last, Once I reboot/restart the Odroid lpcm appears on the HDMI and also with dolby or dts the (incredibly noisy) raw digital spdif signal.
As you probably have a newer TV since it’s HDR10 capable, I would rather go for an ARC setup where you connect both your AVR and Kodi box to your TV and send audio over HDMI through ARC. More information about ARC at Lifewire: What HDMI ARC (Audio Return Channel) Is.
I did try 9.2 but no improvement. As for the optical I found a compatible optical transmitter on Flea Bay - Cliff OTj-8 - It works off the 5 volt GPIO with pin 7 supplying the input.
Thanks for all the helpful suggestions, if a little off topic.
I raised the issue because there is at present no AVR for sale that supports HDR10+, hence SPDIF is the current way to go. As a bonus however I tried upping the SDIF sample rate in Coreelec to 96Khz and to my surprise the amp confirmed flac 96Khz audio files were playing correctly.
I’m using an older AVR which only has a S/PDIF input and had a similar (or even the same) issue.
To resolve it I had to change the Settings/System/Audio/Audio Output Device option to ALSA:AML-AUGESOUND, HDMI and left the Passthrough Output Device option as ALSA:AML-AUGESOUND, S/PDIF