FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavfilter/scale_eval.c
Date: 2026-05-02 17:52:23
Exec Total Coverage
Lines: 20 75 26.7%
Functions: 1 2 50.0%
Branches: 13 48 27.1%

Line Branch Exec Source
1 /*
2 * Copyright (c) 2007 Bobby Bingham
3 *
4 * This file is part of FFmpeg.
5 *
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.
10 *
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.
15 *
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
19 */
20
21 #include <inttypes.h>
22 #include <stdint.h>
23 #include "scale_eval.h"
24 #include "libavutil/eval.h"
25 #include "libavutil/mathematics.h"
26 #include "libavutil/pixdesc.h"
27
28 static const char *const var_names[] = {
29 "in_w", "iw",
30 "in_h", "ih",
31 "out_w", "ow",
32 "out_h", "oh",
33 "a",
34 "sar",
35 "dar",
36 "hsub",
37 "vsub",
38 "ohsub",
39 "ovsub",
40 NULL
41 };
42
43 enum var_name {
44 VAR_IN_W, VAR_IW,
45 VAR_IN_H, VAR_IH,
46 VAR_OUT_W, VAR_OW,
47 VAR_OUT_H, VAR_OH,
48 VAR_A,
49 VAR_SAR,
50 VAR_DAR,
51 VAR_HSUB,
52 VAR_VSUB,
53 VAR_OHSUB,
54 VAR_OVSUB,
55 VARS_NB
56 };
57
58 int ff_scale_eval_dimensions(void *log_ctx,
59 const char *w_expr, const char *h_expr,
60 AVFilterLink *inlink, AVFilterLink *outlink,
61 int *ret_w, int *ret_h)
62 {
63 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
64 const AVPixFmtDescriptor *out_desc = av_pix_fmt_desc_get(outlink->format);
65 const char *expr;
66 int eval_w, eval_h;
67 int ret;
68 double var_values[VARS_NB], res;
69
70 var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
71 var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
72 var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
73 var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
74 var_values[VAR_A] = (double) inlink->w / inlink->h;
75 var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ?
76 (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
77 var_values[VAR_DAR] = var_values[VAR_A] * var_values[VAR_SAR];
78 var_values[VAR_HSUB] = 1 << desc->log2_chroma_w;
79 var_values[VAR_VSUB] = 1 << desc->log2_chroma_h;
80 var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
81 var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;
82
83 /* evaluate width and height */
84 av_expr_parse_and_eval(&res, (expr = w_expr),
85 var_names, var_values,
86 NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
87 var_values[VAR_OUT_W] = var_values[VAR_OW] = res == 0 ? inlink->w : trunc(res);
88
89 if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
90 var_names, var_values,
91 NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
92 goto fail;
93 if (!(res >= INT32_MIN && res <= INT32_MAX)) {
94 ret = AVERROR(EINVAL);
95 goto fail;
96 }
97
98 eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = (int) res == 0 ? inlink->h : (int) res;
99 /* evaluate again the width, as it may depend on the output height */
100 if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
101 var_names, var_values,
102 NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
103 goto fail;
104 if (!(res >= INT32_MIN && res <= INT32_MAX)) {
105 ret = AVERROR(EINVAL);
106 goto fail;
107 }
108 eval_w = (int) res == 0 ? inlink->w : (int) res;
109
110 *ret_w = eval_w;
111 *ret_h = eval_h;
112
113 return 0;
114
115 fail:
116 av_log(log_ctx, AV_LOG_ERROR,
117 "Error when evaluating the expression '%s'.\n"
118 "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
119 expr, w_expr, h_expr);
120 return ret;
121 }
122
123 6677 int ff_scale_adjust_dimensions(AVFilterLink *inlink,
124 int *ret_w, int *ret_h,
125 int force_original_aspect_ratio, int force_divisible_by,
126 double w_adj)
127 {
128 int64_t w, h;
129 int64_t factor_w, factor_h;
130
131 6677 w = *ret_w;
132 6677 h = *ret_h;
133
134 /* Check if it is requested that the result has to be divisible by some
135 * factor (w or h = -n with n being the factor). */
136 6677 factor_w = 1;
137 6677 factor_h = 1;
138
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6677 if (w < -1) {
139 factor_w = -w;
140 }
141
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6677 if (h < -1) {
142 2 factor_h = -h;
143 }
144
145
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6677 if (w < 0 && h < 0) {
146 w = inlink->w * w_adj;
147 h = inlink->h;
148 }
149
150 /* Make sure that the result is divisible by the factor we determined
151 * earlier. If no factor was set, nothing will happen as the default
152 * factor is 1 */
153
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6677 if (w < 0)
154 w = av_rescale(h, inlink->w * w_adj, inlink->h * factor_w) * factor_w;
155
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6677 if (h < 0)
156 3 h = av_rescale(w, inlink->h, inlink->w * w_adj * factor_h) * factor_h;
157
158 /* Note that force_original_aspect_ratio may overwrite the previous set
159 * dimensions so that it is not divisible by the set factors anymore
160 * unless force_divisible_by is defined as well */
161
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6677 if (force_original_aspect_ratio != SCALE_FORCE_OAR_DISABLE) {
162 // Including force_divisible_by here rounds to the nearest multiple of it.
163 int64_t tmp_w = av_rescale(h, inlink->w * w_adj, inlink->h * (int64_t)force_divisible_by)
164 * force_divisible_by;
165 int64_t tmp_h = av_rescale(w, inlink->h, inlink->w * w_adj * (int64_t)force_divisible_by)
166 * force_divisible_by;
167
168 if (force_original_aspect_ratio == SCALE_FORCE_OAR_DECREASE) {
169 w = FFMIN(tmp_w, w);
170 h = FFMIN(tmp_h, h);
171 if (force_divisible_by > 1) {
172 // round down in case provided w or h is not divisible.
173 w = w / force_divisible_by * force_divisible_by;
174 h = h / force_divisible_by * force_divisible_by;
175 }
176 } else { // SCALE_FORCE_OAR_INCREASE
177 w = FFMAX(tmp_w, w);
178 h = FFMAX(tmp_h, h);
179 if (force_divisible_by > 1) {
180 // round up in case provided w or h is not divisible.
181 w = (w + force_divisible_by - 1) / force_divisible_by * force_divisible_by;
182 h = (h + force_divisible_by - 1) / force_divisible_by * force_divisible_by;
183 }
184 }
185 }
186
187
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6677 if ((int32_t)w != w || (int32_t)h != h)
188 return AVERROR(EINVAL);
189
190
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6677 if (w <= 0 || h <= 0) {
191 1 av_log(inlink->dst, AV_LOG_ERROR,
192 "Rescaled dimensions %"PRId64"x%"PRId64" are invalid, "
193 "output dimensions must be positive.\n", w, h);
194 1 return AVERROR(EINVAL);
195 }
196
197 6676 *ret_w = w;
198 6676 *ret_h = h;
199
200 6676 return 0;
201 }
202