On 1., it keeps coming up, but when I was using HDMI for audio into a prepro, I found a Gefen HDMI Dectective+ invaluable along with my then 2k video. If you are doing 4K video, I don't know if there is a similar, always on HDMI spoofer. But, something like that keeps Windows from getting confused on audio. It completely solved my problems.
This is another favorite topic/issues. I have a Monoprice Blackbird 8x8 Matrix switch with EDID programmability.
You would think this would solve it all, but it doesn't. I have lots of TV and movies with multichannel sound. Some are compatible with the EDID set to "4K 7.1" but there are some tv shows that throw the dreaded "playback cannot start on the selected device", by far my worst MC message to see. Always happens to wife when I am not there.
If I play an episode and i get the dreaded message, MC thinks that even though it told me it couldn't play it, it still played ?, it still marks it watched, and it disappears from my view. I have to go into a special view I have just for this error that shows all episodes, watched or not. To get these files to play, I have to tell the EDID to "use output 1" which is the Denon 4k 7.1 Atmos receiver.
MC is happy with seeing the Denon for most files, but there are still some it gives the message. I have theater view option that changes the output to 2.0. We do that for the single episode, and then hopefully remember to switch it back.
It is very frustrating. I have had to go with HDMI, since Spdif can't do 7.1 or Atmos. I get the same delays as the original poster for music (will try padding it with silence... that should wreck havoc on my crossfade settings.)
Also volume normalization seems to ignore the DTS music files and passes them at full volume, where normal 2.0 music is much quieter. Lots of dashes to the volume knob if we intermix DTS with 2.0. I just love the DTS stuff though...
I wish the dreaded "cannot start play on selected device" message would tell me why. What does it think I am missing. Either setting for the EDID switch should provide all the playback capabilities needed for ANY file, but MC isn't happy sometimes.
Don