emulate media key press on Mac

That took some time and many hacks (trying around with ctypes, the IOKit native interface, Quartz and/or Cocoa). This seems like an easy solution now:

#!/usr/bin/python

import Quartz

# NSEvent.h
NSSystemDefined = 14

# hidsystem/ev_keymap.h
NX_KEYTYPE_SOUND_UP = 0
NX_KEYTYPE_SOUND_DOWN = 1
NX_KEYTYPE_PLAY = 16
NX_KEYTYPE_NEXT = 17
NX_KEYTYPE_PREVIOUS = 18
NX_KEYTYPE_FAST = 19
NX_KEYTYPE_REWIND = 20

def HIDPostAuxKey(key):
  def doKey(down):
    ev = Quartz.NSEvent.otherEventWithType_location_modifierFlags_timestamp_windowNumber_context_subtype_data1_data2_(
      NSSystemDefined, # type
      (0,0), # location
      0xa00 if down else 0xb00, # flags
      0, # timestamp
      0, # window
      0, # ctx
      8, # subtype
      (key << 16) | ((0xa if down else 0xb) << 8), # data1
      -1 # data2
      )
    cev = ev.CGEvent()
    Quartz.CGEventPost(0, cev)
  doKey(True)
  doKey(False)

for _ in range(10):
  HIDPostAuxKey(NX_KEYTYPE_SOUND_UP)
HIDPostAuxKey(NX_KEYTYPE_PLAY)

(While I needed this in Python for now, my question was not really Python related and of course you can easily translate that to any other language, esp. ObjC.)