Almost certainly not multi-channel at that size, which is probably why the RPi is happy with it.
Keasy, Kodi is just XBMC renamed, that's exactly what I was using that the Pi struggled with. It's not the player as such (that works fine), it's the size of the file. There's no point having a nice 5.1/7.1 system if you're only ever playing stereo through it, which is why I stopped using mine as it was too flaky with any multi-channel audio. I'd settle for DTS, but really you want the DTS-HD or TrueHD to make the most of what you have.
That said, if you're happy with 1080/2.0, then it should be fine as long as you stay away from the full bitrate 1080. 720/2.0 will be fine though, even at full bitrate.
"Chav kids are like sand people. They're easily startled but they'll be back, and in greater numbers."