2 * Copyright (c) 2007 Bobby Bingham
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include "libavutil/eval.h"
24 #include "libavutil/mathematics.h"
25 #include "libavutil/pixdesc.h"
27 static const char *const var_names[] = {
64 * This must be kept in sync with var_names so that it is always a
65 * complete list of var_names with the scale2ref specific names
66 * appended. scale2ref values must appear in the order they appear
67 * in the var_name_scale2ref enum but also be below all of the
68 * non-scale2ref specific values.
70 static const char *const var_names_scale2ref[] = {
95 enum var_name_scale2ref {
100 VAR_S2R_MAIN_DAR, VAR_S2R_MDAR,
106 int ff_scale_eval_dimensions(void *log_ctx,
107 const char *w_expr, const char *h_expr,
108 AVFilterLink *inlink, AVFilterLink *outlink,
109 int *ret_w, int *ret_h)
111 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
112 const AVPixFmtDescriptor *out_desc = av_pix_fmt_desc_get(outlink->format);
115 int factor_w, factor_h;
118 const char scale2ref = outlink->src->nb_inputs == 2 && outlink->src->inputs[1] == inlink;
119 double var_values[VARS_NB + VARS_S2R_NB], res;
120 const AVPixFmtDescriptor *main_desc;
121 const AVFilterLink *main_link;
122 const char *const *names = scale2ref ? var_names_scale2ref : var_names;
125 main_link = outlink->src->inputs[0];
126 main_desc = av_pix_fmt_desc_get(main_link->format);
129 var_values[VAR_PI] = M_PI;
130 var_values[VAR_PHI] = M_PHI;
131 var_values[VAR_E] = M_E;
132 var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
133 var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
134 var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
135 var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
136 var_values[VAR_A] = (double) inlink->w / inlink->h;
137 var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ?
138 (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
139 var_values[VAR_DAR] = var_values[VAR_A] * var_values[VAR_SAR];
140 var_values[VAR_HSUB] = 1 << desc->log2_chroma_w;
141 var_values[VAR_VSUB] = 1 << desc->log2_chroma_h;
142 var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
143 var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;
146 var_values[VARS_NB + VAR_S2R_MAIN_W] = main_link->w;
147 var_values[VARS_NB + VAR_S2R_MAIN_H] = main_link->h;
148 var_values[VARS_NB + VAR_S2R_MAIN_A] = (double) main_link->w / main_link->h;
149 var_values[VARS_NB + VAR_S2R_MAIN_SAR] = main_link->sample_aspect_ratio.num ?
150 (double) main_link->sample_aspect_ratio.num / main_link->sample_aspect_ratio.den : 1;
151 var_values[VARS_NB + VAR_S2R_MAIN_DAR] = var_values[VARS_NB + VAR_S2R_MDAR] =
152 var_values[VARS_NB + VAR_S2R_MAIN_A] * var_values[VARS_NB + VAR_S2R_MAIN_SAR];
153 var_values[VARS_NB + VAR_S2R_MAIN_HSUB] = 1 << main_desc->log2_chroma_w;
154 var_values[VARS_NB + VAR_S2R_MAIN_VSUB] = 1 << main_desc->log2_chroma_h;
157 /* evaluate width and height */
158 av_expr_parse_and_eval(&res, (expr = w_expr),
160 NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
161 eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = (int) res == 0 ? inlink->w : (int) res;
163 if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
165 NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
167 eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = (int) res == 0 ? inlink->h : (int) res;
168 /* evaluate again the width, as it may depend on the output height */
169 if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
171 NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
173 eval_w = (int) res == 0 ? inlink->w : (int) res;
178 /* Check if it is requested that the result has to be divisible by a some
179 * factor (w or h = -n with n being the factor). */
189 if (w < 0 && h < 0) {
194 /* Make sure that the result is divisible by the factor we determined
195 * earlier. If no factor was set, it is nothing will happen as the default
198 w = av_rescale(h, inlink->w, inlink->h * factor_w) * factor_w;
200 h = av_rescale(w, inlink->h, inlink->w * factor_h) * factor_h;
208 av_log(log_ctx, AV_LOG_ERROR,
209 "Error when evaluating the expression '%s'.\n"
210 "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
211 expr, w_expr, h_expr);