typedef struct XMA2PACKET {  
    int FrameCount : 6;  
    int FrameOffsetInBits : 15;  
    int PacketMetaData : 3;  
    int PacketSkipCount : 8;  
    BYTE XmaData[XMA_BYTES_PER_PACKET - sizeof ( DWORD )];  
} XMA2PACKET  

      // 001100 000001000001111 001 00000010  
      //    |          |         |      |____ Skip 2 packets to find the next one for this stream  
      //    |          |         |___________ XMA2 signature (this is always 001)  
      //    |          |_____________________ First frame starts 527 bits into the packet  
      //    |________________________________ The packet contains 12 frames