MV_B_BACK          64 libavfilter/vf_codecview.c         CONST("bb", "backward predicted MVs of B-frames", MV_B_BACK, "mv"),
MV_B_BACK         272 libavfilter/vf_codecview.c                         (direction == 1 && (s->mv & MV_B_BACK) && frame->pict_type == AV_PICTURE_TYPE_B))