Here's the answer to your question, "Can you play the M4A files directly in Media Center from a local file without going through DLNA?"
I am able to play M4A files directly in Media Center at 24/96, but they do not play through DLNA on PS Audio PW DACII. I am totally unable to play 24/192 M4A whether through Media Center or through DLNA and PW DAC II. With 24/192 ALAC or FLAC on Media Center I get a Core Audio warning that it does not support. FLAC works perfectly for DLNA at all times for all files.
See below for my earlier comment:
Sounds very much like the same problem I am having for some time.
Now using MC for MAC version 18.0.179 with a Firewire external drive. Still having problem described below.
Here's what I wrote on 3/31 -- "Help, please: I am using MC for Mac version 18.0.155 with Mac OS 10.7.5. MC generally works great with wonderful sound -- but with DLNA I can't get M4A/ALAC at 48/24, 96/24 or 192/24, etc. to play with sound. FLAC at 48/24, 96/24 or 192/24, etc. is no problem. Am using MC in DLNA set up with PS Audio PWII DAC. Any idea of what is my problem? Or, is it a bug?
Response on 4/1 was to try different settings for 24 bit; didn't help.