I found that the Multimedia button on my keyboard and IR remote not working in Raspbian.
But it works in OSMC, Ubuntu Mate and Xubuntu.
(All of them are on Raspberry Pi 2B)
The Keyboard and IR remote looks like this

The keycode I see is:
Plau/Pause = 164
Next = 163
Previous = 165
Stop = 166
Volume Up = 115
Volume Down = 114
Mute = 113
So, I want to ask about how Ubuntu Mate and Xubuntu implement this function and can I port this to Raspbian to make make Multimedia Button in Raspbian act as exactly same as Ubuntu Mate and Xubuntu?
(Just think the implement in OSMC are not as same as Ubuntu Mate and Xubuntu...)
Sorry for my poor english and with someone can help me...