for x264, setting deblock field to 0:0 results in deblock=1:-1:-1 being documented in the encoding parameters.
Setting deblock field to 1:-1 gets documented as deblock=1:1:-1,
-1:-1 sets as deblock=1:-1:-1,
-1:-1:0 set as deblock=1:-1:-1
documentation on x264 has it as a <alpha>:<beta> control set.