typedef struct tACMSTREAMHEADER
{
    DWORD           cbStruct;               
    DWORD           fdwStatus;              
    DWORD_PTR       dwUser;                 
    LPBYTE          pbSrc;
    DWORD           cbSrcLength;
    DWORD           cbSrcLengthUsed;
    DWORD_PTR       dwSrcUser;              
    LPBYTE          pbDst;
    DWORD           cbDstLength;
    DWORD           cbDstLengthUsed;
    DWORD_PTR       dwDstUser;              
    DWORD           dwReservedDriver[_DRVRESERVED];   

} ACMSTREAMHEADER, *PACMSTREAMHEADER, FAR *LPACMSTREAMHEADER;