I tried playing with
alsamixer(booting the machine with a LiveCD since OpenELEC has no ALSA mixer application) but all I can get is sound going out through the output jack. With Kodi I can use any HDMI link I wish as the main output but I have come to wondering if both sound hardware can interact…
Input is made through Intel HDA
Realtek ALC892. HDMI is an
Intel Haswell HDMI.
Well obviously you can do it by running a program that reads audio from a capture device and writes it to the HDMI output (potentially through pulseaudio, so you can mix other sounds with it).
I don’t have any specific suggestion for you about what program to look for, sorry.
I think it’s unlikely that two different cards (the analog codec on the mobo, and the Haswell GPU HDMI) can talk to each other without software intervention. I wouldn’t even be confident about being able to get the Realtek audio hardware to internally send audio from its ADC to its digital S/PDIF output.