(1) USE_GUESS_LEVEL = 0: each superblock search and apply best
deblocking filter level. Filter level is transmitted each superblock.

(2) USE_GUESS_LEVEL = 1: use q to guess a filter level for the whole
frame. Only one filter level is transmitted.

Change-Id: I585f6ca0621f5c88fc9d0d95c4fc671114b384c4