For the record I am using LMDE 201109-gnome-dvd-32bit.iso with Update pack 3. Download PS3 Media Server 1.40.0 and making sure dependencies (sudo apt-get install mencoder ffmpeg vlc mplayer sun-java6-jre) installed. Unzip your pms-generic-linux-unix-1.40.0.tgz to your folder of your choice,
goto the "linux" sub-folder and make sure "tsmuxer" is set to allow to execute.
goto the "renderers" sub-folder, open "xbox360.conf" in gedit, goto this line, "StreamExtensions=wma,asf"
and make it look like this "StreamExtensions=wma,asf,avi"
in the "TranscodeExtensions" line right above that, add .mp4 somewhere in that line.
save and close it.
goto main pms folder and make "pms.sh" allow to execute
add "deb http://debian-multimedia.org sid main non-free" to your software sources in package manager
open terminal and "apt update"
then "sudo apt-get install ffmpeg"
i suggest then removing the repo line for sid now as we only used it for ffmpeg then reload so your not getting any updates from it.
now run pms.sh and point it to your media folders, fire up your your 360 goto video library and it should see your PC
as a bonus check it to "start minimized" and add it as a startup application
I only use it for videos but it should handle audio as well. good luck.

