what about
1st round- group of 4-> two go through (32 players)
2nd round- another group of 4-> 1 goes through (8 players)
+3rounds of knock out's to get the winner (4,2,1)
or
1st round- group of 4-> two go through (32 players)
2nd round- another group of 4-> 2 go through (16 players)
+4rounds of knock out's to get the winner (8,4,2,1)