BLEND_SUBTRACT    131 libavfilter/vf_blend.c     { "subtract",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_SUBTRACT},   0, 0, FLAGS, "mode" },\
BLEND_SUBTRACT    340 libavfilter/vf_blend.c         case BLEND_SUBTRACT:   param->blend = blend_subtract;   break;