Action generated when an audio device receives an event.
[Windows Only]
int function(Ihandle *ih, int state); [in C] ih:wom_cb(state: number) -> (ret: number) [in Lua]
ih:
  identifies the element that activated the event.
state: can be opening=1, done=0, or closing=-1.
This callback is used to syncronize video playback with audio. It is sent when the audio device:
| Message | Description | 
|---|---|
| opening | is opened by using the waveOutOpen function. | 
| done | is finished with a data block sent by using the waveOutWrite function. | 
| closing | is closed by using the waveOutClose function. | 
You must use the HWND attribute when calling waveOutOpen in the dwCallback parameter and set fdwOpen to CALLBACK_WINDOW.