BYTE GetXmaChannelMaskFromStandardMask(  
         DWORD dwStandardMask  
)  

__inline BYTE GetXmaChannelMaskFromStandardMask(DWORD dwStandardMask)
{
    BYTE bXmaMask = 0;

    if (dwStandardMask & SPEAKER_FRONT_LEFT)    bXmaMask |= XMA_SPEAKER_LEFT;
    if (dwStandardMask & SPEAKER_FRONT_RIGHT)   bXmaMask |= XMA_SPEAKER_RIGHT;
    if (dwStandardMask & SPEAKER_FRONT_CENTER)  bXmaMask |= XMA_SPEAKER_CENTER;
    if (dwStandardMask & SPEAKER_LOW_FREQUENCY) bXmaMask |= XMA_SPEAKER_LFE;
    if (dwStandardMask & SPEAKER_SIDE_LEFT)     bXmaMask |= XMA_SPEAKER_LEFT_SURROUND;
    if (dwStandardMask & SPEAKER_SIDE_RIGHT)    bXmaMask |= XMA_SPEAKER_RIGHT_SURROUND;
    if (dwStandardMask & SPEAKER_BACK_LEFT)     bXmaMask |= XMA_SPEAKER_LEFT_BACK;
    if (dwStandardMask & SPEAKER_BACK_RIGHT)    bXmaMask |= XMA_SPEAKER_RIGHT_BACK;

    return bXmaMask;
}