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 uint8_t graph[NB_COMP][256];
58 #define OFFSET(x) offsetof(CurvesContext, x)
59 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
60 static const AVOption curves_options[] = {
61 { "red", "set red points coordinates", OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
62 { "r", "set red points coordinates", OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
63 { "green", "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
64 { "g", "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
65 { "blue", "set blue points coordinates", OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
66 { "b", "set blue points coordinates", OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
67 { "preset", "select a color curves preset", OFFSET(preset), AV_OPT_TYPE_INT, {.i64=PRESET_NONE}, PRESET_NONE, NB_PRESETS-1, FLAGS, "preset_name" },
68 { "color_negative", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_COLOR_NEGATIVE}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
69 { "cross_process", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_CROSS_PROCESS}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
70 { "darker", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_DARKER}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
71 { "increase_contrast", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_INCREASE_CONTRAST}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
72 { "lighter", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_LIGHTER}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
73 { "linear_contrast", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_LINEAR_CONTRAST}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
74 { "medium_contrast", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_MEDIUM_CONTRAST}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
75 { "negative", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_NEGATIVE}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
76 { "strong_contrast", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_STRONG_CONTRAST}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
77 { "vintage", NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_VINTAGE}, INT_MIN, INT_MAX, FLAGS, "preset_name" },
81 AVFILTER_DEFINE_CLASS(curves);
87 } curves_presets[] = {
88 [PRESET_COLOR_NEGATIVE] = {
89 "0/1 0.129/1 0.466/0.498 0.725/0 1/0",
90 "0/1 0.109/1 0.301/0.498 0.517/0 1/0",
91 "0/1 0.098/1 0.235/0.498 0.423/0 1/0",
93 [PRESET_CROSS_PROCESS] = {
94 "0.25/0.156 0.501/0.501 0.686/0.745",
95 "0.25/0.188 0.38/0.501 0.745/0.815 1/0.815",
96 "0.231/0.094 0.709/0.874",
99 "0.5/0.4", "0.5/0.4", "0.5/0.4",
101 [PRESET_INCREASE_CONTRAST] = {
102 "0.149/0.066 0.831/0.905 0.905/0.98",
103 "0.149/0.066 0.831/0.905 0.905/0.98",
104 "0.149/0.066 0.831/0.905 0.905/0.98",
107 "0.4/0.5", "0.4/0.5", "0.4/0.5",
109 [PRESET_LINEAR_CONTRAST] = {
110 "0.305/0.286 0.694/0.713",
111 "0.305/0.286 0.694/0.713",
112 "0.305/0.286 0.694/0.713",
114 [PRESET_MEDIUM_CONTRAST] = {
115 "0.286/0.219 0.639/0.643",
116 "0.286/0.219 0.639/0.643",
117 "0.286/0.219 0.639/0.643",
119 [PRESET_NEGATIVE] = {
120 "0/1 1/0", "0/1 1/0", "0/1 1/0",
122 [PRESET_STRONG_CONTRAST] = {
123 "0.301/0.196 0.592/0.6 0.686/0.737",
124 "0.301/0.196 0.592/0.6 0.686/0.737",
125 "0.301/0.196 0.592/0.6 0.686/0.737",
128 "0/0.11 0.42/0.51 1/0.95",
130 "0/0.22 0.49/0.44 1/0.8",
134 static struct keypoint *make_point(double x, double y, struct keypoint *next)
136 struct keypoint *point = av_mallocz(sizeof(*point));
146 static int parse_points_str(AVFilterContext *ctx, struct keypoint **points, const char *s)
148 char *p = (char *)s; // strtod won't alter the string
149 struct keypoint *last = NULL;
151 /* construct a linked list based on the key points string */
153 struct keypoint *point = make_point(0, 0, NULL);
155 return AVERROR(ENOMEM);
156 point->x = av_strtod(p, &p); if (p && *p) p++;
157 point->y = av_strtod(p, &p); if (p && *p) p++;
158 if (point->x < 0 || point->x > 1 || point->y < 0 || point->y > 1) {
159 av_log(ctx, AV_LOG_ERROR, "Invalid key point coordinates (%f;%f), "
160 "x and y must be in the [0;1] range.\n", point->x, point->y);
161 return AVERROR(EINVAL);
166 if ((int)(last->x * 255) >= (int)(point->x * 255)) {
167 av_log(ctx, AV_LOG_ERROR, "Key point coordinates (%f;%f) "
168 "and (%f;%f) are too close from each other or not "
169 "strictly increasing on the x-axis\n",
170 last->x, last->y, point->x, point->y);
171 return AVERROR(EINVAL);
178 /* auto insert first key point if missing at x=0 */
180 last = make_point(0, 0, NULL);
182 return AVERROR(ENOMEM);
183 last->x = last->y = 0;
185 } else if ((*points)->x != 0.) {
186 struct keypoint *newfirst = make_point(0, 0, *points);
188 return AVERROR(ENOMEM);
194 /* auto insert last key point if missing at x=1 */
196 struct keypoint *point = make_point(1, 1, NULL);
198 return AVERROR(ENOMEM);
205 static int get_nb_points(const struct keypoint *d)
216 * Natural cubic spline interpolation
217 * Finding curves using Cubic Splines notes by Steven Rauch and John Stockie.
218 * @see http://people.math.sfu.ca/~stockie/teaching/macm316/notes/splines.pdf
220 static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *points)
223 const struct keypoint *point;
226 int n = get_nb_points(points); // number of splines
228 double (*matrix)[3] = av_calloc(n, sizeof(*matrix));
229 double *h = av_malloc((n - 1) * sizeof(*h));
230 double *r = av_calloc(n, sizeof(*r));
232 if (!matrix || !h || !r) {
233 ret = AVERROR(ENOMEM);
237 /* h(i) = x(i+1) - x(i) */
239 for (point = points; point; point = point->next) {
241 h[i] = point->x - xprev;
246 /* right-side of the polynomials, will be modified to contains the solution */
248 for (i = 1; i < n - 1; i++) {
249 double yp = point->y,
251 yn = point->next->next->y;
252 r[i] = 6 * ((yn-yc)/h[i] - (yc-yp)/h[i-1]);
256 #define B 0 /* sub diagonal (below main) */
257 #define M 1 /* main diagonal (center) */
258 #define A 2 /* sup diagonal (above main) */
260 /* left side of the polynomials into a tridiagonal matrix. */
261 matrix[0][M] = matrix[n - 1][M] = 1;
262 for (i = 1; i < n - 1; i++) {
263 matrix[i][B] = h[i-1];
264 matrix[i][M] = 2 * (h[i-1] + h[i]);
268 /* tridiagonal solving of the linear system */
269 for (i = 1; i < n; i++) {
270 double den = matrix[i][M] - matrix[i][B] * matrix[i-1][A];
271 double k = den ? 1./den : 1.;
273 r[i] = (r[i] - matrix[i][B] * r[i - 1]) * k;
275 for (i = n - 2; i >= 0; i--)
276 r[i] = r[i] - matrix[i][A] * r[i + 1];
278 /* compute the graph with x=[0..255] */
281 av_assert0(point->next); // always at least 2 key points
282 while (point->next) {
283 double yc = point->y;
284 double yn = point->next->y;
287 double b = (yn-yc)/h[i] - h[i]*r[i]/2. - h[i]*(r[i+1]-r[i])/6.;
288 double c = r[i] / 2.;
289 double d = (r[i+1] - r[i]) / (6.*h[i]);
292 int x_start = point->x * 255;
293 int x_end = point->next->x * 255;
295 av_assert0(x_start >= 0 && x_start <= 255 &&
296 x_end >= 0 && x_end <= 255);
298 for (x = x_start; x <= x_end; x++) {
299 double xx = (x - x_start) * 1/255.;
300 double yy = a + b*xx + c*xx*xx + d*xx*xx*xx;
301 y[x] = av_clipf(yy, 0, 1) * 255;
302 av_log(ctx, AV_LOG_DEBUG, "f(%f)=%f -> y[%d]=%d\n", xx, yy, x, y[x]);
316 static av_cold int init(AVFilterContext *ctx, const char *args)
319 CurvesContext *curves = ctx->priv;
320 struct keypoint *comp_points[NB_COMP] = {0};
322 if (curves->preset != PRESET_NONE) {
323 char **pts = curves->comp_points_str;
324 if (pts[0] || pts[1] || pts[2]) {
325 av_log(ctx, AV_LOG_ERROR, "It is not possible to mix a preset "
326 "with explicit points placements\n");
327 return AVERROR(EINVAL);
329 pts[0] = av_strdup(curves_presets[curves->preset].r);
330 pts[1] = av_strdup(curves_presets[curves->preset].g);
331 pts[2] = av_strdup(curves_presets[curves->preset].b);
332 if (!pts[0] || !pts[1] || !pts[2])
333 return AVERROR(ENOMEM);
336 for (i = 0; i < NB_COMP; i++) {
337 ret = parse_points_str(ctx, comp_points + i, curves->comp_points_str[i]);
340 ret = interpolate(ctx, curves->graph[i], comp_points[i]);
345 if (av_log_get_level() >= AV_LOG_VERBOSE) {
346 for (i = 0; i < NB_COMP; i++) {
347 struct keypoint *point = comp_points[i];
348 av_log(ctx, AV_LOG_VERBOSE, "#%d points:", i);
350 av_log(ctx, AV_LOG_VERBOSE, " (%f;%f)", point->x, point->y);
353 av_log(ctx, AV_LOG_VERBOSE, "\n");
354 av_log(ctx, AV_LOG_VERBOSE, "#%d values:", i);
355 for (j = 0; j < 256; j++)
356 av_log(ctx, AV_LOG_VERBOSE, " %02X", curves->graph[i][j]);
357 av_log(ctx, AV_LOG_VERBOSE, "\n");
361 for (i = 0; i < NB_COMP; i++) {
362 struct keypoint *point = comp_points[i];
364 struct keypoint *next = point->next;
373 static int query_formats(AVFilterContext *ctx)
375 static const enum AVPixelFormat pix_fmts[] = {AV_PIX_FMT_RGB24, AV_PIX_FMT_NONE};
376 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
380 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
382 int x, y, i, direct = 0;
383 AVFilterContext *ctx = inlink->dst;
384 CurvesContext *curves = ctx->priv;
385 AVFilterLink *outlink = inlink->dst->outputs[0];
390 if (av_frame_is_writable(in)) {
394 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
397 return AVERROR(ENOMEM);
399 av_frame_copy_props(out, in);
405 for (y = 0; y < inlink->h; y++) {
407 const uint8_t *srcp = src;
409 for (x = 0; x < inlink->w; x++)
410 for (i = 0; i < NB_COMP; i++, dstp++, srcp++)
411 *dstp = curves->graph[i][*srcp];
412 dst += out->linesize[0];
413 src += in ->linesize[0];
419 return ff_filter_frame(outlink, out);
422 static const AVFilterPad curves_inputs[] = {
425 .type = AVMEDIA_TYPE_VIDEO,
426 .filter_frame = filter_frame,
431 static const AVFilterPad curves_outputs[] = {
434 .type = AVMEDIA_TYPE_VIDEO,
439 static const char *const shorthand[] = { "preset", NULL };
441 AVFilter avfilter_vf_curves = {
443 .description = NULL_IF_CONFIG_SMALL("Adjust components curves."),
444 .priv_size = sizeof(CurvesContext),
446 .query_formats = query_formats,
447 .inputs = curves_inputs,
448 .outputs = curves_outputs,
449 .priv_class = &curves_class,
450 .shorthand = shorthand,