SMOOTHDOWN        168 libavfilter/vf_xfade.c     {   "smoothdown", "smoothdown transition",  0, AV_OPT_TYPE_CONST, {.i64=SMOOTHDOWN}, 0, 0, FLAGS, "transition" },
SMOOTHDOWN       1411 libavfilter/vf_xfade.c     case SMOOTHDOWN: s->transitionf = s->depth <= 8 ? smoothdown8_transition : smoothdown16_transition; break;