modeCoding.txt

mode_inv == 15 : 160994+150352 = 311346  ->  1
mode_inv == 14 : 23175+19610   = 42785   ->  001
mode_inv == 13 : 22856+19621   = 42477   ->  011
mode_inv == 12 : 22907+13419   = 36326   ->  0100
mode_inv == 11 : 16761+23462   = 40223   ->  0101
mode_inv == 10 : 3993+2928     = 6921    ->  000001
mode_inv ==  9 : 260+1097      = 1357    ->  000000001
mode_inv ==  7 : 14200+19191   = 33391   ->  0001
mode_inv ==  6 : 15550+15545   = 31095   ->  00001
mode_inv ==  5 : 685+1041      = 1726    ->  0000001
mode_inv ==  4 : 35+79         = 114     ->  00000000

Huffman compression:

((4 + 9) + 5) + 10) + 6) + 7 _+_ 14
(11 + 12) _+_ 13 

                       O
                     /   \
                   15      O
                         /   \
                       O       O
                     /   \    /  \
                   13     O  14   O
                        /   \    / \
                      11    12  7   O
                                   / \
                                  6   O
                                     / \
                                   10   O
                                       / \
                                      5   O
                                         / \
                                        9   4

Because modes never goes consequently in one word -> no prefix-free requirement!
First bit is 1 -> mode_inv == 15, otherwise second bit is 1 ->  use remaining 2 bits to code 4 modes: 7,11,13,14;
otherwise use 3 bits to code remaining 6 modes: 12,10,6,9,5,3
For example:
15 -> 1
14 -> 0111
13 -> 0110
11 -> 0101
7  -> 0100
12 -> 00111
10 -> 00110
6  -> 00101
9  -> 00100
5  -> 00011
3  -> 00010
and invalid modes are 00001 and 00000