FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavfilter/vf_grayworld.c
Date: 2024-07-24 19:24:46
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Lines: 0 124 0.0%
Functions: 0 9 0.0%
Branches: 0 36 0.0%

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1 /*
2 * Copyright (c) 2021 Paul Buxton
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 /**
22 * @file
23 * Color correction filter based on
24 * https://www.researchgate.net/publication/275213614_A_New_Color_Correction_Method_for_Underwater_Imaging
25 *
26 */
27
28 #include "libavutil/imgutils.h"
29 #include "libavutil/mem.h"
30
31 #include "avfilter.h"
32 #include "internal.h"
33 #include "video.h"
34
35 typedef struct ThreadData {
36 AVFrame *in, *out;
37 float l_avg;
38 float a_avg;
39 float b_avg;
40 } ThreadData;
41
42 typedef struct GrayWorldContext {
43 float *tmpplab;
44 int *line_count_pels;
45 float *line_sum;
46 } GrayWorldContext;
47
48 static void apply_matrix(const float matrix[3][3], const float input[3], float output[3])
49 {
50 output[0] = matrix[0][0] * input[0] + matrix[0][1] * input[1] + matrix[0][2] * input[2];
51 output[1] = matrix[1][0] * input[0] + matrix[1][1] * input[1] + matrix[1][2] * input[2];
52 output[2] = matrix[2][0] * input[0] + matrix[2][1] * input[1] + matrix[2][2] * input[2];
53 }
54
55 static const float lms2lab[3][3] = {
56 {0.5774, 0.5774, 0.5774},
57 {0.40825, 0.40825, -0.816458},
58 {0.707, -0.707, 0}
59 };
60
61 static const float lab2lms[3][3] = {
62 {0.57735, 0.40825, 0.707},
63 {0.57735, 0.40825, -0.707},
64 {0.57735, -0.8165, 0}
65 };
66
67 static const float rgb2lms[3][3] = {
68 {0.3811, 0.5783, 0.0402},
69 {0.1967, 0.7244, 0.0782},
70 {0.0241, 0.1288, 0.8444}
71 };
72
73 static const float lms2rgb[3][3] = {
74 {4.4679, -3.5873, 0.1193},
75 {-1.2186, 2.3809, -0.1624},
76 {0.0497, -0.2439, 1.2045}
77 };
78
79 /**
80 * Convert from Linear RGB to logspace LAB
81 *
82 * @param rgb Input array of rgb components
83 * @param lab output array of lab components
84 */
85 static void rgb2lab(const float rgb[3], float lab[3])
86 {
87 float lms[3];
88
89 apply_matrix(rgb2lms, rgb, lms);
90 lms[0] = lms[0] > 0.f ? logf(lms[0]) : -1024.f;
91 lms[1] = lms[1] > 0.f ? logf(lms[1]) : -1024.f;
92 lms[2] = lms[2] > 0.f ? logf(lms[2]) : -1024.f;
93 apply_matrix(lms2lab, lms, lab);
94 }
95
96 /**
97 * Convert from Logspace LAB to Linear RGB
98 *
99 * @param lab input array of lab components
100 * @param rgb output array of rgb components
101 */
102 static void lab2rgb(const float lab[3], float rgb[3])
103 {
104 float lms[3];
105
106 apply_matrix(lab2lms, lab, lms);
107 lms[0] = expf(lms[0]);
108 lms[1] = expf(lms[1]);
109 lms[2] = expf(lms[2]);
110 apply_matrix(lms2rgb, lms, rgb);
111 }
112
113 /**
114 * Convert a frame from linear RGB to logspace LAB, and accumulate channel totals for each row
115 * Convert from RGB -> lms using equation 4 in color transfer paper.
116 *
117 * @param ctx Filter context
118 * @param arg Thread data pointer
119 * @param jobnr job number
120 * @param nb_jobs number of jobs
121 */
122 static int convert_frame(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
123 {
124 GrayWorldContext *s = ctx->priv;
125 ThreadData *td = arg;
126 AVFrame *in = td->in;
127 AVFrame *out = td->out;
128 AVFilterLink *outlink = ctx->outputs[0];
129 const int slice_start = (out->height * jobnr) / nb_jobs;
130 const int slice_end = (out->height * (jobnr + 1)) / nb_jobs;
131 float rgb[3], lab[3];
132
133 for (int i = slice_start; i < slice_end; i++) {
134 float *b_in_row = (float *)(in->data[1] + i * in->linesize[1]);
135 float *g_in_row = (float *)(in->data[0] + i * in->linesize[0]);
136 float *r_in_row = (float *)(in->data[2] + i * in->linesize[2]);
137 float *acur = s->tmpplab + i * outlink->w + outlink->w * outlink->h;
138 float *bcur = s->tmpplab + i * outlink->w + 2 * outlink->w * outlink->h;
139 float *lcur = s->tmpplab + i * outlink->w;
140
141 s->line_sum[i] = 0.f;
142 s->line_sum[i + outlink->h] = 0.f;
143 s->line_count_pels[i] = 0;
144
145 for (int j = 0; j < outlink->w; j++) {
146 rgb[0] = r_in_row[j];
147 rgb[1] = g_in_row[j];
148 rgb[2] = b_in_row[j];
149 rgb2lab(rgb, lab);
150 *(lcur++) = lab[0];
151 *(acur++) = lab[1];
152 *(bcur++) = lab[2];
153 s->line_sum[i] += lab[1];
154 s->line_sum[i + outlink->h] += lab[2];
155 s->line_count_pels[i]++;
156 }
157 }
158 return 0;
159 }
160
161 /**
162 * Sum the channel totals and compute the mean for each channel
163 *
164 * @param s Frame context
165 * @param td thread data
166 */
167 static void compute_correction(GrayWorldContext *s, ThreadData *td)
168 {
169 float asum = 0.f, bsum = 0.f;
170 int pixels = 0;
171
172 for (int y = 0; y < td->out->height; y++) {
173 asum += s->line_sum[y];
174 bsum += s->line_sum[y + td->out->height];
175 pixels += s->line_count_pels[y];
176 }
177
178 td->a_avg = asum / pixels;
179 td->b_avg = bsum / pixels;
180 }
181
182 /**
183 * Subtract the mean logspace AB values from each pixel.
184 *
185 * @param ctx Filter context
186 * @param arg Thread data pointer
187 * @param jobnr job number
188 * @param nb_jobs number of jobs
189 */
190 static int correct_frame(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
191 {
192 GrayWorldContext *s = ctx->priv;
193 ThreadData *td = arg;
194 AVFrame *out = td->out;
195 AVFilterLink *outlink = ctx->outputs[0];
196 const int slice_start = (out->height * jobnr) / nb_jobs;
197 const int slice_end = (out->height * (jobnr + 1)) / nb_jobs;
198 float rgb[3], lab[3];
199
200 for (int i = slice_start; i < slice_end; i++) {
201 float *g_out_row = (float *)(out->data[0] + i * out->linesize[0]);
202 float *b_out_row = (float *)(out->data[1] + i * out->linesize[1]);
203 float *r_out_row = (float *)(out->data[2] + i * out->linesize[2]);
204 float *lcur = s->tmpplab + i * outlink->w;
205 float *acur = s->tmpplab + i * outlink->w + outlink->w * outlink->h;
206 float *bcur = s->tmpplab + i * outlink->w + 2 * outlink->w * outlink->h;
207
208 for (int j = 0; j < outlink->w; j++) {
209 lab[0] = *lcur++;
210 lab[1] = *acur++;
211 lab[2] = *bcur++;
212
213 // subtract the average for the color channels
214 lab[1] -= td->a_avg;
215 lab[2] -= td->b_avg;
216
217 //convert back to linear rgb
218 lab2rgb(lab, rgb);
219 r_out_row[j] = rgb[0];
220 g_out_row[j] = rgb[1];
221 b_out_row[j] = rgb[2];
222 }
223 }
224 return 0;
225 }
226
227 static int config_input(AVFilterLink *inlink)
228 {
229 GrayWorldContext *s = inlink->dst->priv;
230
231 FF_ALLOC_TYPED_ARRAY(s->tmpplab, inlink->h * inlink->w * 3);
232 FF_ALLOC_TYPED_ARRAY(s->line_count_pels, inlink->h);
233 FF_ALLOC_TYPED_ARRAY(s->line_sum, inlink->h * 2);
234 if (!s->tmpplab || !s->line_count_pels || !s->line_sum)
235 return AVERROR(ENOMEM);
236
237 return 0;
238 }
239
240 static av_cold void uninit(AVFilterContext *ctx)
241 {
242 GrayWorldContext *s = ctx->priv;
243
244 av_freep(&s->tmpplab);
245 av_freep(&s->line_count_pels);
246 av_freep(&s->line_sum);
247 }
248
249 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
250 {
251 AVFilterContext *ctx = inlink->dst;
252 GrayWorldContext *s = ctx->priv;
253 AVFilterLink *outlink = ctx->outputs[0];
254 ThreadData td;
255 AVFrame *out;
256
257 if (av_frame_is_writable(in)) {
258 out = in;
259 } else {
260 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
261 if (!out) {
262 av_frame_free(&in);
263 return AVERROR(ENOMEM);
264 }
265 av_frame_copy_props(out, in);
266 }
267 /* input and output transfer will be linear */
268 if (in->color_trc == AVCOL_TRC_UNSPECIFIED) {
269 av_log(s, AV_LOG_WARNING, "Untagged transfer, assuming linear light.\n");
270 out->color_trc = AVCOL_TRC_LINEAR;
271 } else if (in->color_trc != AVCOL_TRC_LINEAR) {
272 av_log(s, AV_LOG_WARNING, "Gray world color correction works on linear light only.\n");
273 }
274
275 td.in = in;
276 td.out = out;
277
278 ff_filter_execute(ctx, convert_frame, &td, NULL, FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
279 compute_correction(s, &td);
280 ff_filter_execute(ctx, correct_frame, &td, NULL, FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
281
282 if (in != out) {
283 av_image_copy_plane(out->data[3], out->linesize[3],
284 in->data[3], in->linesize[3], outlink->w * 4, outlink->h);
285 av_frame_free(&in);
286 }
287
288 return ff_filter_frame(outlink, out);
289 }
290
291 static const AVFilterPad grayworld_inputs[] = {
292 {
293 .name = "default",
294 .type = AVMEDIA_TYPE_VIDEO,
295 .filter_frame = filter_frame,
296 .config_props = config_input,
297 }
298 };
299
300 const AVFilter ff_vf_grayworld = {
301 .name = "grayworld",
302 .description = NULL_IF_CONFIG_SMALL("Adjust white balance using LAB gray world algorithm"),
303 .priv_size = sizeof(GrayWorldContext),
304 FILTER_INPUTS(grayworld_inputs),
305 FILTER_OUTPUTS(ff_video_default_filterpad),
306 FILTER_PIXFMTS(AV_PIX_FMT_GBRPF32, AV_PIX_FMT_GBRAPF32),
307 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
308 .uninit = uninit,
309 };
310