MV_B_BACK          54 libavfilter/vf_codecview.c         {"bb", "backward predicted MVs of B-frames", 0, AV_OPT_TYPE_CONST, {.i64 = MV_B_BACK }, INT_MIN, INT_MAX, FLAGS, "mv"},
MV_B_BACK         208 libavfilter/vf_codecview.c                 (direction == 1 && (s->mv & MV_B_BACK) && frame->pict_type == AV_PICTURE_TYPE_B))