+static double set_colorquant_ratio_meta(AVFrame *out, int nb_out, int nb_in)
+{
+ char buf[32];
+ const double ratio = (double)nb_out / nb_in;
+ snprintf(buf, sizeof(buf), "%f", ratio);
+ av_dict_set(&out->metadata, "lavfi.color_quant_ratio", buf, 0);
+ return ratio;
+}
+