You don't need any of the MCE stuff, MC does it all and does it better, including TV Tuner stuff
Are you using MC18?
I think the latest betas include a feature to allow different outputs depending on the type of content being played.
I might be wrong though, I've been very busy and have not followed all the latest release info.
If that doesn't work then you need to use S/PDIF but you do realize that doesn't support all multichannel formats, most notably the higher samplerates (>96Khz) which are supported for 2 channel only. Some older receivers might not even support 24-bits over S/PDIF and simply strip the 4 extra bits.
I guess you could setup MC to decode your stuff to your channel setup (5.1?) and resample it to 24 bits/48 Khz. The annoying thing here is that if you have high samplerate audio that would get downsampled too.
There are probably better solutions though, this is what I could come up with for now
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