Black MIDI Wiki
The Windows Multimedia Wrapper is a replacement for Windows Multimedia (WinMM.dll) made by KaleidonKep99, which aims to get rid of the bottleneck caused by the midiOutShortMsg function, which is used by most MIDI applications to output MIDI events to the synthesizer.

It is only available for OmniMIDI, and will NOT WORK with other MIDI drivers.

As of June 6, 2018, this patch makes OmniMIDI the best performing MIDI driver available.

How does it work?[]

Windows allows developers to make apps load DLLs from their own directory first, before being redirected to the system folder.

The wrapper takes advantage of this function, by replacing various important functions with its own, and redirecting the rest of the calls to the real Windows Multimedia API's DLL.

Why is it not compatible with other MIDI drivers?[]

The wrapper is NOT compatible with other MIDI drivers because it takes advantage of a new API introduced in OmniMIDI, called KDMAPI (Keppy's Direct MIDI API).



  • Completely gets rid of the bottleneck caused by midiOutShortMsg, making it faster than any other patch available. (Even the one based on ReactOS files)
  • Beats Windows 7 in MIDI performance.


  • Only works with OmniMIDI.