typedef struct tWAVEFORMATEX
{
    WORD        wFormatTag;         
    WORD        nChannels;          
    DWORD       nSamplesPerSec;     
    DWORD       nAvgBytesPerSec;    
    WORD        nBlockAlign;        
    WORD        wBitsPerSample;     
    WORD        cbSize;             
                                    
} WAVEFORMATEX, *PWAVEFORMATEX, NEAR *NPWAVEFORMATEX, FAR *LPWAVEFORMATEX;

typedef WAVEFORMATEX       *PWAVEFORMATEX;