PRESET_LINEAR_CONTRAST   86 libavfilter/vf_curves.c         { "linear_contrast",    NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_LINEAR_CONTRAST},      INT_MIN, INT_MAX, FLAGS, "preset_name" },
PRESET_LINEAR_CONTRAST  125 libavfilter/vf_curves.c     [PRESET_LINEAR_CONTRAST]    = { .master = "0.305/0.286 0.694/0.713" },