anchor.diff:      is_integer_and_float/1,
       to_nothing/1,
       to_arg/1,
  -    to_dotargs/1
  +    to_dotargs/1,
  +    to_kvarg/1
   ]).
   
   -define(OPTIONS, [
  
positive.code:   {bitstream_filters,      output, "-bsf",                   [{{?MODULE, is_list_and_list}, to_dotargs}, {{erlang, is_list}, to_arg}]},
    {timecode,               output, "-timecode",              [{{erlang, is_list}, to_arg}]},
    {strict,                 output, "-strict",                [{{erlang, is_list}, to_arg}]},
  
    {x264_profile,           output, "-profile",               [{{?MODULE, is_list_and_list}, to_dotargs}]},
    {x264_level,             output, "-level",                 [{{erlang, is_float}, to_arg}]},
  
negative.code:   ":" ++ X ++ " " ++ float_to_list(Y);
  to_dotargs([X, true]) when is_list(X) ->
    ":" ++ X.
  to_kvarg([K, V]) when is_list(K), is_list(V) ->
    lists:flatten(io_lib:format(" ~s=~p", [K, V])).
  