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
22 #include "scale_eval.h"
23 #include "libavutil/eval.h"
24 #include "libavutil/mathematics.h"
25 #include "libavutil/pixdesc.h"
27 static const char *const var_names[] = {
57 int ff_scale_eval_dimensions(void *log_ctx,
58 const char *w_expr, const char *h_expr,
59 AVFilterLink *inlink, AVFilterLink *outlink,
60 int *ret_w, int *ret_h)
62 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
63 const AVPixFmtDescriptor *out_desc = av_pix_fmt_desc_get(outlink->format);
67 double var_values[VARS_NB], res;
69 var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
70 var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
71 var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
72 var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
73 var_values[VAR_A] = (double) inlink->w / inlink->h;
74 var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ?
75 (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
76 var_values[VAR_DAR] = var_values[VAR_A] * var_values[VAR_SAR];
77 var_values[VAR_HSUB] = 1 << desc->log2_chroma_w;
78 var_values[VAR_VSUB] = 1 << desc->log2_chroma_h;
79 var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
80 var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;
82 /* evaluate width and height */
83 av_expr_parse_and_eval(&res, (expr = w_expr),
84 var_names, var_values,
85 NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
86 eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = (int) res == 0 ? inlink->w : (int) res;
88 if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
89 var_names, var_values,
90 NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
92 eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = (int) res == 0 ? inlink->h : (int) res;
93 /* evaluate again the width, as it may depend on the output height */
94 if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
95 var_names, var_values,
96 NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
98 eval_w = (int) res == 0 ? inlink->w : (int) res;
106 av_log(log_ctx, AV_LOG_ERROR,
107 "Error when evaluating the expression '%s'.\n"
108 "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
109 expr, w_expr, h_expr);
113 int ff_scale_adjust_dimensions(AVFilterLink *inlink,
114 int *ret_w, int *ret_h,
115 int force_original_aspect_ratio, int force_divisible_by)
118 int factor_w, factor_h;
123 /* Check if it is requested that the result has to be divisible by some
124 * factor (w or h = -n with n being the factor). */
134 if (w < 0 && h < 0) {
139 /* Make sure that the result is divisible by the factor we determined
140 * earlier. If no factor was set, nothing will happen as the default
143 w = av_rescale(h, inlink->w, inlink->h * factor_w) * factor_w;
145 h = av_rescale(w, inlink->h, inlink->w * factor_h) * factor_h;
147 /* Note that force_original_aspect_ratio may overwrite the previous set
148 * dimensions so that it is not divisible by the set factors anymore
149 * unless force_divisible_by is defined as well */
150 if (force_original_aspect_ratio) {
151 int tmp_w = av_rescale(h, inlink->w, inlink->h);
152 int tmp_h = av_rescale(w, inlink->h, inlink->w);
154 if (force_original_aspect_ratio == 1) {
157 if (force_divisible_by > 1) {
159 w = w / force_divisible_by * force_divisible_by;
160 h = h / force_divisible_by * force_divisible_by;
165 if (force_divisible_by > 1) {
167 w = (w + force_divisible_by - 1) / force_divisible_by * force_divisible_by;
168 h = (h + force_divisible_by - 1) / force_divisible_by * force_divisible_by;