[FFmpeg-cvslog] lavfi: add curves filter.
Clément Bœsch
git at videolan.org
Sun Mar 10 03:00:59 CET 2013
ffmpeg | branch: master | Clément Bœsch <ubitux at gmail.com> | Mon Mar 4 16:06:14 2013 +0100| [65fc80f0121dd1514160defb97a8bbcab072c58b] | committer: Clément Bœsch
lavfi: add curves filter.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=65fc80f0121dd1514160defb97a8bbcab072c58b
---
Changelog | 4 +
doc/filters.texi | 67 +++++++++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/version.h | 2 +-
libavfilter/vf_curves.c | 363 ++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 437 insertions(+), 1 deletion(-)
diff --git a/Changelog b/Changelog
index a535864..bff5a1d 100644
--- a/Changelog
+++ b/Changelog
@@ -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
diff --git a/doc/filters.texi b/doc/filters.texi
index 88a52ac..3febd2e 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -2217,6 +2217,73 @@ indicates never reset and return the largest area encountered during
playback.
@end table
+ at 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
+ at 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.
+
+ at table @option
+ at item red, r
+Set the key points for the red component.
+ at item green, g
+Set the key points for the green component.
+ at item blue, b
+Set the key points for the blue component.
+ at 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 ...}.
+
+ at subsection Examples
+
+ at itemize
+ at item
+Increase slightly the middle level of blue:
+ at example
+curves=blue='0.5/0.58'
+ at end example
+
+ at item
+Vintage effect:
+ at 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'
+ at end example
+Here we obtain the following coordinates for each components:
+ at table @var
+ at item red
+ at code{(0;0.11) (0.42;0.51) (1;0.95)}
+ at item green
+ at code{(0;0) (0.50;0.48) (1;1)}
+ at item blue
+ at code{(0;0.22) (0.49;0.44) (1;0.80)}
+ at end table
+ at end itemize
+
@section decimate
Drop frames that do not differ greatly from the previous frame in
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 229ae83..a391de8 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -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
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 141a9a7..f9e5d50 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -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);
diff --git a/libavfilter/version.h b/libavfilter/version.h
index bc3b405..598397b 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -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, \
diff --git a/libavfilter/vf_curves.c b/libavfilter/vf_curves.c
new file mode 100644
index 0000000..7fee90a
--- /dev/null
+++ b/libavfilter/vf_curves.c
@@ -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,
+};
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