2 * Copyright (c) 2013 Clément Bœsch
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
21 #include "libavutil/opt.h"
22 #include "libavutil/eval.h"
23 #include "libavutil/avassert.h"
31 struct keypoint *next;
38 PRESET_COLOR_NEGATIVE,
41 PRESET_INCREASE_CONTRAST,
43 PRESET_LINEAR_CONTRAST,
44 PRESET_MEDIUM_CONTRAST,
46 PRESET_STRONG_CONTRAST,
54 char *comp_points_str[NB_COMP];
55 char *comp_points_str_all;
56 uint8_t graph[NB_COMP][256];
59 #define OFFSET(x) offsetof(CurvesContext, x)
60 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
61 static const AVOption curves_options[] = {
62 { "preset", "select a color curves preset", OFFSET(preset), AV_OPT_TYPE_INT, {.i64=PRESET_NONE}, PRESET_NONE, NB_PRESETS-1, FLAGS, "preset_name" },
63 { "none", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_NONE}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
64 { "color_negative", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_COLOR_NEGATIVE}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
65 { "cross_process", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_CROSS_PROCESS}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
66 { "darker", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_DARKER}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
67 { "increase_contrast", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_INCREASE_CONTRAST}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
68 { "lighter", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_LIGHTER}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
69 { "linear_contrast", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_LINEAR_CONTRAST}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
70 { "medium_contrast", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_MEDIUM_CONTRAST}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
71 { "negative", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_NEGATIVE}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
72 { "strong_contrast", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_STRONG_CONTRAST}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
73 { "vintage", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_VINTAGE}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
74 { "red", "set red points coordinates", OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
75 { "r", "set red points coordinates", OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
76 { "green", "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
77 { "g", "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
78 { "blue", "set blue points coordinates", OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
79 { "b", "set blue points coordinates", OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
80 { "all", "set points coordinates for all components", OFFSET(comp_points_str_all), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
84 AVFILTER_DEFINE_CLASS(curves);
91 } curves_presets[] = {
92 [PRESET_COLOR_NEGATIVE] = {
93 "0/1 0.129/1 0.466/0.498 0.725/0 1/0",
94 "0/1 0.109/1 0.301/0.498 0.517/0 1/0",
95 "0/1 0.098/1 0.235/0.498 0.423/0 1/0",
97 [PRESET_CROSS_PROCESS] = {
98 "0.25/0.156 0.501/0.501 0.686/0.745",
99 "0.25/0.188 0.38/0.501 0.745/0.815 1/0.815",
100 "0.231/0.094 0.709/0.874",
102 [PRESET_DARKER] = { .all = "0.5/0.4" },
103 [PRESET_INCREASE_CONTRAST] = { .all = "0.149/0.066 0.831/0.905 0.905/0.98" },
104 [PRESET_LIGHTER] = { .all = "0.4/0.5" },
105 [PRESET_LINEAR_CONTRAST] = { .all = "0.305/0.286 0.694/0.713" },
106 [PRESET_MEDIUM_CONTRAST] = { .all = "0.286/0.219 0.639/0.643" },
107 [PRESET_NEGATIVE] = { .all = "0/1 1/0" },
108 [PRESET_STRONG_CONTRAST] = { .all = "0.301/0.196 0.592/0.6 0.686/0.737" },
110 "0/0.11 0.42/0.51 1/0.95",
112 "0/0.22 0.49/0.44 1/0.8",
116 static struct keypoint *make_point(double x, double y, struct keypoint *next)
118 struct keypoint *point = av_mallocz(sizeof(*point));
128 static int parse_points_str(AVFilterContext *ctx, struct keypoint **points, const char *s)
130 char *p = (char *)s; // strtod won't alter the string
131 struct keypoint *last = NULL;
133 /* construct a linked list based on the key points string */
135 struct keypoint *point = make_point(0, 0, NULL);
137 return AVERROR(ENOMEM);
138 point->x = av_strtod(p, &p); if (p && *p) p++;
139 point->y = av_strtod(p, &p); if (p && *p) p++;
140 if (point->x < 0 || point->x > 1 || point->y < 0 || point->y > 1) {
141 av_log(ctx, AV_LOG_ERROR, "Invalid key point coordinates (%f;%f), "
142 "x and y must be in the [0;1] range.\n", point->x, point->y);
143 return AVERROR(EINVAL);
148 if ((int)(last->x * 255) >= (int)(point->x * 255)) {
149 av_log(ctx, AV_LOG_ERROR, "Key point coordinates (%f;%f) "
150 "and (%f;%f) are too close from each other or not "
151 "strictly increasing on the x-axis\n",
152 last->x, last->y, point->x, point->y);
153 return AVERROR(EINVAL);
160 /* auto insert first key point if missing at x=0 */
162 last = make_point(0, 0, NULL);
164 return AVERROR(ENOMEM);
165 last->x = last->y = 0;
167 } else if ((*points)->x != 0.) {
168 struct keypoint *newfirst = make_point(0, 0, *points);
170 return AVERROR(ENOMEM);
176 /* auto insert last key point if missing at x=1 */
178 struct keypoint *point = make_point(1, 1, NULL);
180 return AVERROR(ENOMEM);
187 static int get_nb_points(const struct keypoint *d)
198 * Natural cubic spline interpolation
199 * Finding curves using Cubic Splines notes by Steven Rauch and John Stockie.
200 * @see http://people.math.sfu.ca/~stockie/teaching/macm316/notes/splines.pdf
202 static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *points)
205 const struct keypoint *point;
208 int n = get_nb_points(points); // number of splines
210 double (*matrix)[3] = av_calloc(n, sizeof(*matrix));
211 double *h = av_malloc((n - 1) * sizeof(*h));
212 double *r = av_calloc(n, sizeof(*r));
214 if (!matrix || !h || !r) {
215 ret = AVERROR(ENOMEM);
219 /* h(i) = x(i+1) - x(i) */
221 for (point = points; point; point = point->next) {
223 h[i] = point->x - xprev;
228 /* right-side of the polynomials, will be modified to contains the solution */
230 for (i = 1; i < n - 1; i++) {
231 double yp = point->y,
233 yn = point->next->next->y;
234 r[i] = 6 * ((yn-yc)/h[i] - (yc-yp)/h[i-1]);
238 #define B 0 /* sub diagonal (below main) */
239 #define M 1 /* main diagonal (center) */
240 #define A 2 /* sup diagonal (above main) */
242 /* left side of the polynomials into a tridiagonal matrix. */
243 matrix[0][M] = matrix[n - 1][M] = 1;
244 for (i = 1; i < n - 1; i++) {
245 matrix[i][B] = h[i-1];
246 matrix[i][M] = 2 * (h[i-1] + h[i]);
250 /* tridiagonal solving of the linear system */
251 for (i = 1; i < n; i++) {
252 double den = matrix[i][M] - matrix[i][B] * matrix[i-1][A];
253 double k = den ? 1./den : 1.;
255 r[i] = (r[i] - matrix[i][B] * r[i - 1]) * k;
257 for (i = n - 2; i >= 0; i--)
258 r[i] = r[i] - matrix[i][A] * r[i + 1];
260 /* compute the graph with x=[0..255] */
263 av_assert0(point->next); // always at least 2 key points
264 while (point->next) {
265 double yc = point->y;
266 double yn = point->next->y;
269 double b = (yn-yc)/h[i] - h[i]*r[i]/2. - h[i]*(r[i+1]-r[i])/6.;
270 double c = r[i] / 2.;
271 double d = (r[i+1] - r[i]) / (6.*h[i]);
274 int x_start = point->x * 255;
275 int x_end = point->next->x * 255;
277 av_assert0(x_start >= 0 && x_start <= 255 &&
278 x_end >= 0 && x_end <= 255);
280 for (x = x_start; x <= x_end; x++) {
281 double xx = (x - x_start) * 1/255.;
282 double yy = a + b*xx + c*xx*xx + d*xx*xx*xx;
283 y[x] = av_clipf(yy, 0, 1) * 255;
284 av_log(ctx, AV_LOG_DEBUG, "f(%f)=%f -> y[%d]=%d\n", xx, yy, x, y[x]);
298 static av_cold int init(AVFilterContext *ctx)
301 CurvesContext *curves = ctx->priv;
302 struct keypoint *comp_points[NB_COMP] = {0};
303 char **pts = curves->comp_points_str;
304 const char *allp = curves->comp_points_str_all;
306 if (!allp && curves->preset != PRESET_NONE && curves_presets[curves->preset].all)
307 allp = curves_presets[curves->preset].all;
310 for (i = 0; i < NB_COMP; i++) {
312 pts[i] = av_strdup(allp);
314 return AVERROR(ENOMEM);
318 if (curves->preset != PRESET_NONE) {
319 if (!pts[0]) pts[0] = av_strdup(curves_presets[curves->preset].r);
320 if (!pts[1]) pts[1] = av_strdup(curves_presets[curves->preset].g);
321 if (!pts[2]) pts[2] = av_strdup(curves_presets[curves->preset].b);
322 if (!pts[0] || !pts[1] || !pts[2])
323 return AVERROR(ENOMEM);
326 for (i = 0; i < NB_COMP; i++) {
327 ret = parse_points_str(ctx, comp_points + i, curves->comp_points_str[i]);
330 ret = interpolate(ctx, curves->graph[i], comp_points[i]);
335 if (av_log_get_level() >= AV_LOG_VERBOSE) {
336 for (i = 0; i < NB_COMP; i++) {
337 struct keypoint *point = comp_points[i];
338 av_log(ctx, AV_LOG_VERBOSE, "#%d points:", i);
340 av_log(ctx, AV_LOG_VERBOSE, " (%f;%f)", point->x, point->y);
343 av_log(ctx, AV_LOG_VERBOSE, "\n");
344 av_log(ctx, AV_LOG_VERBOSE, "#%d values:", i);
345 for (j = 0; j < 256; j++)
346 av_log(ctx, AV_LOG_VERBOSE, " %02X", curves->graph[i][j]);
347 av_log(ctx, AV_LOG_VERBOSE, "\n");
351 for (i = 0; i < NB_COMP; i++) {
352 struct keypoint *point = comp_points[i];
354 struct keypoint *next = point->next;
363 static int query_formats(AVFilterContext *ctx)
365 static const enum AVPixelFormat pix_fmts[] = {AV_PIX_FMT_RGB24, AV_PIX_FMT_NONE};
366 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
370 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
372 int x, y, i, direct = 0;
373 AVFilterContext *ctx = inlink->dst;
374 CurvesContext *curves = ctx->priv;
375 AVFilterLink *outlink = inlink->dst->outputs[0];
380 if (av_frame_is_writable(in)) {
384 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
387 return AVERROR(ENOMEM);
389 av_frame_copy_props(out, in);
395 for (y = 0; y < inlink->h; y++) {
397 const uint8_t *srcp = src;
399 for (x = 0; x < inlink->w; x++)
400 for (i = 0; i < NB_COMP; i++, dstp++, srcp++)
401 *dstp = curves->graph[i][*srcp];
402 dst += out->linesize[0];
403 src += in ->linesize[0];
409 return ff_filter_frame(outlink, out);
412 static const AVFilterPad curves_inputs[] = {
415 .type = AVMEDIA_TYPE_VIDEO,
416 .filter_frame = filter_frame,
421 static const AVFilterPad curves_outputs[] = {
424 .type = AVMEDIA_TYPE_VIDEO,
429 AVFilter avfilter_vf_curves = {
431 .description = NULL_IF_CONFIG_SMALL("Adjust components curves."),
432 .priv_size = sizeof(CurvesContext),
434 .query_formats = query_formats,
435 .inputs = curves_inputs,
436 .outputs = curves_outputs,
437 .priv_class = &curves_class,