A while ago, I posted my setup to control mpv through keypresses. It was done through JSON IPC.
MPRIS d-bus interface
I recently learned about the MPRIS D-Bus interface. It stands for Media Player Remote Interfacing Specification, and this is exactly what I was looking for. The problem with JSON IPC is that it would only support one player instance. That is, if I had one instance of mpv playing something, and then start another instance, the keyboard control would not work anymore after the second instance exited.
To get it to work on arch, there are two aur packages:
mpv-mpris is an mpv addon to implement the d-bus interface for mpv.
mpris2controller is a user daemon to monitor mpris enabled programs so that commands are always sent to the correct application.
Finally, my updated i3 config is now:
bindsym XF86AudioPlay exec "mpris2controller PlayPause" bindsym XF86AudioPause exec "mpris2controller PlayPause" bindsym XF86AudioStop exec "mpris2controller PlayPause" bindsym XF86AudioPrev exec "mpris2controller Previous" bindsym XF86AudioNext exec "mpris2controller Next" bindsym $mod+Control+n exec "mpris2controller Next" bindsym $mod+Control+p exec "mpris2controller Previous" bindsym $mod+Control+m exec "get_music_info"
get_music_info is a small utility to retrieve some metadata and send a notification. It's useful when you're listening to something random and think "oh, that's cool, what is this track?".