@@ -2,6 +2,10 @@ Entries are sorted chronologically from oldest to youngest within each release,

 releases are sorted from youngest to oldest.

 version <next>:

+- curves filter

+

+

+version 1.2:

 - VDPAU hardware acceleration through normal hwaccel

 - SRTP support

@@ -2217,6 +2217,73 @@ indicates never reset and return the largest area encountered during

 playback.

 @end table

+@section curves

+

+Apply color adjustments using curves.

+

+This filter is similar to the Adobe Photoshop and GIMP curves tools. Each

+component (red, green and blue) has its values defined by @var{N} key points

+tied from each other using a smooth curve. The x-axis represents the pixel

+values from the input frame, and the y-axis the new pixel values to be set for

+the output frame.

+

+By default, a component curve is defined by the two points @var{(0;0)} and

+@var{(1;1)}. This creates a straight line where each original pixel value is

+"adjusted" to its own value, which means no change to the image.

+

+The filter allows you to redefine these two points and add some more. A new

+curve (using a natural cubic spline interpolation) will be define to pass

+smoothly through all these new coordinates. The new defined points needs to be

+strictly increasing over the x-axis, and their @var{x} and @var{y} values must

+be in the @var{[0;1]} interval.  If the computed curves happened to go outside

+the vector spaces, the values will be clipped accordingly.

+

+If there is no key point defined in @code{x=0}, the filter will automatically

+insert a @var{(0;0)} point. In the same way, if there is no key point defined

+in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.

+

+The filter accepts parameters as a list of @var{key}=@var{value} pairs,

+separated by ":".

+

+A description of the accepted parameters follows.

+

+@table @option

+@item red, r

+Set the key points for the red component.

+@item green, g

+Set the key points for the green component.

+@item blue, b

+Set the key points for the blue component.

+@end table

+

+To avoid some filtergraph syntax conflicts, each key points list need to be

+defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.

+

+@subsection Examples

+

+@itemize

+@item

+Increase slightly the middle level of blue:

+@example

+curves=blue='0.5/0.58'

+@end example

+

+@item

+Vintage effect:

+@example

+curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'

+@end example

+Here we obtain the following coordinates for each components:

+@table @var

+@item red

+@code{(0;0.11) (0.42;0.51) (1;0.95)}

+@item green

+@code{(0;0) (0.50;0.48) (1;1)}

+@item blue

+@code{(0;0.22) (0.49;0.44) (1;0.80)}

+@end table

+@end itemize

+

 @section decimate

 Drop frames that do not differ greatly from the previous frame in

@@ -104,6 +104,7 @@ OBJS-$(CONFIG_COLORMATRIX_FILTER)            += vf_colormatrix.o

 OBJS-$(CONFIG_COPY_FILTER)                   += vf_copy.o

 OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o

 OBJS-$(CONFIG_CROPDETECT_FILTER)             += vf_cropdetect.o

+OBJS-$(CONFIG_CURVES_FILTER)                 += vf_curves.o

 OBJS-$(CONFIG_DECIMATE_FILTER)               += vf_decimate.o

 OBJS-$(CONFIG_DELOGO_FILTER)                 += vf_delogo.o

 OBJS-$(CONFIG_DESHAKE_FILTER)                += vf_deshake.o

@@ -100,6 +100,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER(COPY,           copy,           vf);

     REGISTER_FILTER(CROP,           crop,           vf);

     REGISTER_FILTER(CROPDETECT,     cropdetect,     vf);

+    REGISTER_FILTER(CURVES,         curves,         vf);

     REGISTER_FILTER(DECIMATE,       decimate,       vf);

     REGISTER_FILTER(DELOGO,         delogo,         vf);

     REGISTER_FILTER(DESHAKE,        deshake,        vf);

@@ -29,7 +29,7 @@

 #include "libavutil/avutil.h"

 #define LIBAVFILTER_VERSION_MAJOR  3

-#define LIBAVFILTER_VERSION_MINOR  43

+#define LIBAVFILTER_VERSION_MINOR  44

 #define LIBAVFILTER_VERSION_MICRO 100

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

new file mode 100644

@@ -0,0 +1,363 @@

+/*

+ * Copyright (c) 2013 Clément Bœsch

+ *

+ * This file is part of FFmpeg.

+ *

+ * FFmpeg is free software; you can redistribute it and/or

+ * modify it under the terms of the GNU Lesser General Public

+ * License as published by the Free Software Foundation; either

+ * version 2.1 of the License, or (at your option) any later version.

+ *

+ * FFmpeg is distributed in the hope that it will be useful,

+ * but WITHOUT ANY WARRANTY; without even the implied warranty of

+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+ * Lesser General Public License for more details.

+ *

+ * You should have received a copy of the GNU Lesser General Public

+ * License along with FFmpeg; if not, write to the Free Software

+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

+ */

+

+#include "libavutil/opt.h"

+#include "libavutil/eval.h"

+#include "libavutil/avassert.h"

+#include "avfilter.h"

+#include "formats.h"

+#include "internal.h"

+#include "video.h"

+

+struct keypoint {

+    double x, y;

+    struct keypoint *next;

+};

+

+#define NB_COMP 3

+

+typedef struct {

+    const AVClass *class;

+    char *comp_points_str[NB_COMP];

+    uint8_t graph[NB_COMP][256];

+} CurvesContext;

+

+#define OFFSET(x) offsetof(CurvesContext, x)

+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

+static const AVOption curves_options[] = {

+    { "red",   "set red points coordinates",   OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },

+    { "r",     "set red points coordinates",   OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },

+    { "green", "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },

+    { "g",     "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },

+    { "blue",  "set blue points coordinates",  OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },

+    { "b",     "set blue points coordinates",  OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },

+    { NULL }

+};

+

+AVFILTER_DEFINE_CLASS(curves);

+

+static struct keypoint *make_point(double x, double y, struct keypoint *next)

+{

+    struct keypoint *point = av_mallocz(sizeof(*point));

+

+    if (!point)

+        return NULL;

+    point->x = x;

+    point->y = y;

+    point->next = next;

+    return point;

+}

+

+static int parse_points_str(AVFilterContext *ctx, struct keypoint **points, const char *s)

+{

+    char *p = (char *)s; // strtod won't alter the string

+    struct keypoint *last = NULL;

+

+    /* construct a linked list based on the key points string */

+    while (p && *p) {

+        struct keypoint *point = make_point(0, 0, NULL);

+        if (!point)

+            return AVERROR(ENOMEM);

+        point->x = av_strtod(p, &p); if (p && *p) p++;

+        point->y = av_strtod(p, &p); if (p && *p) p++;

+        if (point->x < 0 || point->x > 1 || point->y < 0 || point->y > 1) {

+            av_log(ctx, AV_LOG_ERROR, "Invalid key point coordinates (%f;%f), "

+                   "x and y must be in the [0;1] range.\n", point->x, point->y);

+            return AVERROR(EINVAL);

+        }

+        if (!*points)

+            *points = point;

+        if (last) {

+            if ((int)(last->x * 255) >= (int)(point->x * 255)) {

+                av_log(ctx, AV_LOG_ERROR, "Key point coordinates (%f;%f) "

+                       "and (%f;%f) are too close from each other or not "

+                       "strictly increasing on the x-axis\n",

+                       last->x, last->y, point->x, point->y);

+                return AVERROR(EINVAL);

+            }

+            last->next = point;

+        }

+        last = point;

+    }

+

+    /* auto insert first key point if missing at x=0 */

+    if (!*points) {

+        last = make_point(0, 0, NULL);

+        if (!last)

+            return AVERROR(ENOMEM);

+        last->x = last->y = 0;

+        *points = last;

+    } else if ((*points)->x != 0.) {

+        struct keypoint *newfirst = make_point(0, 0, *points);

+        if (!newfirst)

+            return AVERROR(ENOMEM);

+        *points = newfirst;

+    }

+

+    av_assert0(last);

+

+    /* auto insert last key point if missing at x=1 */

+    if (last->x != 1.) {

+        struct keypoint *point = make_point(1, 1, NULL);

+        if (!point)

+            return AVERROR(ENOMEM);

+        last->next = point;

+    }

+

+    return 0;

+}

+

+static int get_nb_points(const struct keypoint *d)

+{

+    int n = 0;

+    while (d) {

+        n++;

+        d = d->next;

+    }

+    return n;

+}

+

+/**

+ * Natural cubic spline interpolation

+ * Finding curves using Cubic Splines notes by Steven Rauch and John Stockie.

+ * @see http://people.math.sfu.ca/~stockie/teaching/macm316/notes/splines.pdf

+ */

+static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *points)

+{

+    int i, ret = 0;

+    const struct keypoint *point;

+    double xprev = 0;

+

+    int n = get_nb_points(points); // number of splines

+

+    double (*matrix)[3] = av_calloc(n, sizeof(*matrix));

+    double *h = av_malloc((n - 1) * sizeof(*h));

+    double *r = av_calloc(n, sizeof(*r));

+

+    if (!matrix || !h || !r) {

+        ret = AVERROR(ENOMEM);

+        goto end;

+    }

+

+    /* h(i) = x(i+1) - x(i) */

+    i = -1;

+    for (point = points; point; point = point->next) {

+        if (i != -1)

+            h[i] = point->x - xprev;

+        xprev = point->x;

+        i++;

+    }

+

+    /* right-side of the polynomials, will be modified to contains the solution */

+    point = points;

+    for (i = 1; i < n - 1; i++) {

+        double yp = point->y,

+               yc = point->next->y,

+               yn = point->next->next->y;

+        r[i] = 6 * ((yn-yc)/h[i] - (yc-yp)/h[i-1]);

+        point = point->next;

+    }

+

+#define B 0 /* sub  diagonal (below main) */

+#define M 1 /* main diagonal (center) */

+#define A 2 /* sup  diagonal (above main) */

+

+    /* left side of the polynomials into a tridiagonal matrix. */

+    matrix[0][M] = matrix[n - 1][M] = 1;

+    for (i = 1; i < n - 1; i++) {

+        matrix[i][B] = h[i-1];

+        matrix[i][M] = 2 * (h[i-1] + h[i]);

+        matrix[i][A] = h[i];

+    }

+

+    /* tridiagonal solving of the linear system */

+    for (i = 1; i < n; i++) {

+        double den = matrix[i][M] - matrix[i][B] * matrix[i-1][A];

+        double k = den ? 1./den : 1.;

+        matrix[i][A] *= k;

+        r[i] = (r[i] - matrix[i][B] * r[i - 1]) * k;

+    }

+    for (i = n - 2; i >= 0; i--)

+        r[i] = r[i] - matrix[i][A] * r[i + 1];

+

+    /* compute the graph with x=[0..255] */

+    i = 0;

+    point = points;

+    av_assert0(point->next); // always at least 2 key points

+    while (point->next) {

+        double yc = point->y;

+        double yn = point->next->y;

+

+        double a = yc;

+        double b = (yn-yc)/h[i] - h[i]*r[i]/2. - h[i]*(r[i+1]-r[i])/6.;

+        double c = r[i] / 2.;

+        double d = (r[i+1] - r[i]) / (6.*h[i]);

+

+        int x;

+        int x_start = point->x       * 255;

+        int x_end   = point->next->x * 255;

+

+        av_assert0(x_start >= 0 && x_start <= 255 &&

+                   x_end   >= 0 && x_end   <= 255);

+

+        for (x = x_start; x <= x_end; x++) {

+            double xx = (x - x_start) * 1/255.;

+            double yy = a + b*xx + c*xx*xx + d*xx*xx*xx;

+            y[x] = av_clipf(yy, 0, 1) * 255;

+            av_log(ctx, AV_LOG_DEBUG, "f(%f)=%f -> y[%d]=%d\n", xx, yy, x, y[x]);

+        }

+

+        point = point->next;

+        i++;

+    }

+

+end:

+    av_free(matrix);

+    av_free(h);

+    av_free(r);

+    return ret;

+}

+

+static av_cold int init(AVFilterContext *ctx, const char *args)

+{

+    int i, j, ret;

+    CurvesContext *curves = ctx->priv;

+    struct keypoint *comp_points[NB_COMP] = {0};

+

+    curves->class = &curves_class;

+    av_opt_set_defaults(curves);

+

+    if ((ret = av_set_options_string(curves, args, "=", ":")) < 0)

+        return ret;

+

+    for (i = 0; i < NB_COMP; i++) {

+        ret = parse_points_str(ctx, comp_points + i, curves->comp_points_str[i]);

+        if (ret < 0)

+            return ret;

+        ret = interpolate(ctx, curves->graph[i], comp_points[i]);

+        if (ret < 0)

+            return ret;

+    }

+

+    if (av_log_get_level() >= AV_LOG_VERBOSE) {

+        for (i = 0; i < NB_COMP; i++) {

+            struct keypoint *point = comp_points[i];

+            av_log(ctx, AV_LOG_VERBOSE, "#%d points:", i);

+            while (point) {

+                av_log(ctx, AV_LOG_VERBOSE, " (%f;%f)", point->x, point->y);

+                point = point->next;

+            }

+            av_log(ctx, AV_LOG_VERBOSE, "\n");

+            av_log(ctx, AV_LOG_VERBOSE, "#%d values:", i);

+            for (j = 0; j < 256; j++)

+                av_log(ctx, AV_LOG_VERBOSE, " %02X", curves->graph[i][j]);

+            av_log(ctx, AV_LOG_VERBOSE, "\n");

+        }

+    }

+

+    for (i = 0; i < NB_COMP; i++) {

+        struct keypoint *point = comp_points[i];

+        while (point) {

+            struct keypoint *next = point->next;

+            av_free(point);

+            point = next;

+        }

+    }

+

+    av_opt_free(curves);

+    return 0;

+}

+

+static int query_formats(AVFilterContext *ctx)

+{

+    static const enum AVPixelFormat pix_fmts[] = {AV_PIX_FMT_RGB24, AV_PIX_FMT_NONE};

+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));

+    return 0;

+}

+

+static int filter_frame(AVFilterLink *inlink, AVFrame *in)

+{

+    int x, y, i, direct = 0;

+    AVFilterContext *ctx = inlink->dst;

+    CurvesContext *curves = ctx->priv;

+    AVFilterLink *outlink = inlink->dst->outputs[0];

+    AVFrame *out;

+    uint8_t *dst;

+    const uint8_t *src;

+

+    if (av_frame_is_writable(in)) {

+        direct = 1;

+        out = in;

+    } else {

+        out = ff_get_video_buffer(outlink, outlink->w, outlink->h);

+        if (!out) {

+            av_frame_free(&in);

+            return AVERROR(ENOMEM);

+        }

+        av_frame_copy_props(out, in);

+    }

+

+    dst = out->data[0];

+    src = in ->data[0];

+

+    for (y = 0; y < inlink->h; y++) {

+        uint8_t *dstp = dst;

+        const uint8_t *srcp = src;

+

+        for (x = 0; x < inlink->w; x++)

+            for (i = 0; i < NB_COMP; i++, dstp++, srcp++)

+                *dstp = curves->graph[i][*srcp];

+        dst += out->linesize[0];

+        src += in ->linesize[0];

+    }

+

+    if (!direct)

+        av_frame_free(&in);

+

+    return ff_filter_frame(outlink, out);

+}

+

+static const AVFilterPad curves_inputs[] = {

+    {

+        .name         = "default",

+        .type         = AVMEDIA_TYPE_VIDEO,

+        .filter_frame = filter_frame,

+    },

+    { NULL }

+};

+

+static const AVFilterPad curves_outputs[] = {

+     {

+         .name = "default",

+         .type = AVMEDIA_TYPE_VIDEO,

+     },

+     { NULL }

+};

+

+AVFilter avfilter_vf_curves = {

+    .name          = "curves",

+    .description   = NULL_IF_CONFIG_SMALL("Adjust components curves."),

+    .priv_size     = sizeof(CurvesContext),

+    .init          = init,

+    .query_formats = query_formats,

+    .inputs        = curves_inputs,

+    .outputs       = curves_outputs,

+    .priv_class    = &curves_class,

+};