The DMUS_IO_MUTE structure contains information about a mute event on a channel. It is used in the Mute Track Chunk.
typedef struct _DMUS_IO_MUTE {
    MUSIC_TIME  mtTime;
    DWORD       dwPChannel;
    DWORD       dwPChannelMap;
} DMUS_IO_MUTE;
   Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in dmusicf.h.