VAR_S2R_MAIN_VSUB  198 libavfilter/vf_scale.c          vars_w[VAR_S2R_MAIN_VSUB] || vars_h[VAR_S2R_MAIN_VSUB] ||
VAR_S2R_MAIN_VSUB  448 libavfilter/vf_scale.c         scale->var_values[VAR_S2R_MAIN_VSUB] = 1 << main_desc->log2_chroma_h;