LOWER_NIBBLE
#define V_SIZE_HI LOWER_NIBBLE( (unsigned)block[ 14 ] )
#define H_BLANKING_HI LOWER_NIBBLE( (unsigned)block[ 4 ] )
#define V_BLANKING_HI LOWER_NIBBLE( (unsigned)block[ 7 ] )
#define V_SYNC_WIDTH_LO LOWER_NIBBLE( (unsigned)block[ 10 ] )