+static int config_input(AVFilterLink *link)
+{
+ AVFilterContext *ctx = link->dst;
+ CropContext *s = ctx->priv;
+ const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);
+ int ret;
+ const char *expr;
+ double res;
+
+ s->var_values[VAR_E] = M_E;
+ s->var_values[VAR_PHI] = M_PHI;
+ s->var_values[VAR_PI] = M_PI;
+ s->var_values[VAR_IN_W] = s->var_values[VAR_IW] = ctx->inputs[0]->w;
+ s->var_values[VAR_IN_H] = s->var_values[VAR_IH] = ctx->inputs[0]->h;
+ s->var_values[VAR_X] = NAN;
+ s->var_values[VAR_Y] = NAN;
+ s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = NAN;
+ s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = NAN;
+ s->var_values[VAR_N] = 0;
+ s->var_values[VAR_T] = NAN;
+
+ av_image_fill_max_pixsteps(s->max_step, NULL, pix_desc);
+ s->hsub = pix_desc->log2_chroma_w;
+ s->vsub = pix_desc->log2_chroma_h;
+
+ if ((ret = av_expr_parse_and_eval(&res, (expr = s->ow_expr),
+ var_names, s->var_values,
+ NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
+ goto fail_expr;
+ s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = res;
+ if ((ret = av_expr_parse_and_eval(&res, (expr = s->oh_expr),
+ var_names, s->var_values,
+ NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
+ goto fail_expr;
+ s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = res;
+ /* evaluate again ow as it may depend on oh */
+ if ((ret = av_expr_parse_and_eval(&res, (expr = s->ow_expr),
+ var_names, s->var_values,
+ NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
+ goto fail_expr;
+
+ s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = res;
+ if (normalize_double(&s->w, s->var_values[VAR_OUT_W]) < 0 ||
+ normalize_double(&s->h, s->var_values[VAR_OUT_H]) < 0) {
+ av_log(ctx, AV_LOG_ERROR,
+ "Too big value or invalid expression for out_w/ow or out_h/oh. "
+ "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
+ s->ow_expr, s->oh_expr);
+ return AVERROR(EINVAL);
+ }
+ s->w &= ~((1 << s->hsub) - 1);
+ s->h &= ~((1 << s->vsub) - 1);
+
+ av_expr_free(s->x_pexpr);
+ av_expr_free(s->y_pexpr);
+ s->x_pexpr = s->y_pexpr = NULL;
+ if ((ret = av_expr_parse(&s->x_pexpr, s->x_expr, var_names,
+ NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
+ (ret = av_expr_parse(&s->y_pexpr, s->y_expr, var_names,
+ NULL, NULL, NULL, NULL, 0, ctx)) < 0)
+ return AVERROR(EINVAL);