VAR_S2R_MAIN_N    199 libavfilter/vf_scale.c          vars_w[VAR_S2R_MAIN_N]    || vars_h[VAR_S2R_MAIN_N]    ||
VAR_S2R_MAIN_N    210 libavfilter/vf_scale.c          vars_w[VAR_S2R_MAIN_N]   || vars_h[VAR_S2R_MAIN_N]  ||
VAR_S2R_MAIN_N    704 libavfilter/vf_scale.c             scale->var_values[VAR_S2R_MAIN_N] = link->frame_count_out;