lavfi: add curves filter.
This commit is contained in:
Clément Bœsch
parent
3d813e7ec3
commit
65fc80f012
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@ -2,6 +2,10 @@ Entries are sorted chronologically from oldest to youngest within each release,
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releases are sorted from youngest to oldest.
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version <next>:
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- curves filter
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version 1.2:
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- VDPAU hardware acceleration through normal hwaccel
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- SRTP support
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@ -2217,6 +2217,73 @@ indicates never reset and return the largest area encountered during
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playback.
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@end table
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@section curves
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Apply color adjustments using curves.
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This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
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component (red, green and blue) has its values defined by @var{N} key points
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tied from each other using a smooth curve. The x-axis represents the pixel
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values from the input frame, and the y-axis the new pixel values to be set for
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the output frame.
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By default, a component curve is defined by the two points @var{(0;0)} and
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@var{(1;1)}. This creates a straight line where each original pixel value is
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"adjusted" to its own value, which means no change to the image.
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The filter allows you to redefine these two points and add some more. A new
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curve (using a natural cubic spline interpolation) will be define to pass
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smoothly through all these new coordinates. The new defined points needs to be
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strictly increasing over the x-axis, and their @var{x} and @var{y} values must
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be in the @var{[0;1]} interval. If the computed curves happened to go outside
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the vector spaces, the values will be clipped accordingly.
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If there is no key point defined in @code{x=0}, the filter will automatically
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insert a @var{(0;0)} point. In the same way, if there is no key point defined
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in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
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The filter accepts parameters as a list of @var{key}=@var{value} pairs,
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separated by ":".
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A description of the accepted parameters follows.
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@table @option
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@item red, r
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Set the key points for the red component.
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@item green, g
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Set the key points for the green component.
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@item blue, b
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Set the key points for the blue component.
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@end table
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To avoid some filtergraph syntax conflicts, each key points list need to be
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defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
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@subsection Examples
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@itemize
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@item
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Increase slightly the middle level of blue:
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@example
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curves=blue='0.5/0.58'
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@end example
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@item
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Vintage effect:
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@example
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curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
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@end example
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Here we obtain the following coordinates for each components:
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@table @var
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@item red
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@code{(0;0.11) (0.42;0.51) (1;0.95)}
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@item green
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@code{(0;0) (0.50;0.48) (1;1)}
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@item blue
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@code{(0;0.22) (0.49;0.44) (1;0.80)}
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@end table
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@end itemize
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@section decimate
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Drop frames that do not differ greatly from the previous frame in
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@ -104,6 +104,7 @@ OBJS-$(CONFIG_COLORMATRIX_FILTER) += vf_colormatrix.o
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OBJS-$(CONFIG_COPY_FILTER) += vf_copy.o
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OBJS-$(CONFIG_CROP_FILTER) += vf_crop.o
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OBJS-$(CONFIG_CROPDETECT_FILTER) += vf_cropdetect.o
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OBJS-$(CONFIG_CURVES_FILTER) += vf_curves.o
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OBJS-$(CONFIG_DECIMATE_FILTER) += vf_decimate.o
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OBJS-$(CONFIG_DELOGO_FILTER) += vf_delogo.o
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OBJS-$(CONFIG_DESHAKE_FILTER) += vf_deshake.o
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@ -100,6 +100,7 @@ void avfilter_register_all(void)
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REGISTER_FILTER(COPY, copy, vf);
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REGISTER_FILTER(CROP, crop, vf);
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REGISTER_FILTER(CROPDETECT, cropdetect, vf);
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REGISTER_FILTER(CURVES, curves, vf);
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REGISTER_FILTER(DECIMATE, decimate, vf);
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REGISTER_FILTER(DELOGO, delogo, vf);
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REGISTER_FILTER(DESHAKE, deshake, vf);
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@ -29,7 +29,7 @@
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#include "libavutil/avutil.h"
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#define LIBAVFILTER_VERSION_MAJOR 3
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#define LIBAVFILTER_VERSION_MINOR 43
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#define LIBAVFILTER_VERSION_MINOR 44
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#define LIBAVFILTER_VERSION_MICRO 100
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#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
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@ -0,0 +1,363 @@
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/*
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* Copyright (c) 2013 Clément Bœsch
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/opt.h"
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#include "libavutil/eval.h"
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#include "libavutil/avassert.h"
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#include "avfilter.h"
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#include "formats.h"
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#include "internal.h"
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#include "video.h"
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struct keypoint {
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double x, y;
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struct keypoint *next;
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};
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#define NB_COMP 3
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typedef struct {
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const AVClass *class;
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char *comp_points_str[NB_COMP];
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uint8_t graph[NB_COMP][256];
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} CurvesContext;
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#define OFFSET(x) offsetof(CurvesContext, x)
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#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
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static const AVOption curves_options[] = {
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{ "red", "set red points coordinates", OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
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{ "r", "set red points coordinates", OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
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{ "green", "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
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{ "g", "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
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{ "blue", "set blue points coordinates", OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
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{ "b", "set blue points coordinates", OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(curves);
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static struct keypoint *make_point(double x, double y, struct keypoint *next)
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{
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struct keypoint *point = av_mallocz(sizeof(*point));
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if (!point)
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return NULL;
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point->x = x;
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point->y = y;
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point->next = next;
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return point;
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}
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static int parse_points_str(AVFilterContext *ctx, struct keypoint **points, const char *s)
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{
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char *p = (char *)s; // strtod won't alter the string
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struct keypoint *last = NULL;
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/* construct a linked list based on the key points string */
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while (p && *p) {
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struct keypoint *point = make_point(0, 0, NULL);
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if (!point)
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return AVERROR(ENOMEM);
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point->x = av_strtod(p, &p); if (p && *p) p++;
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point->y = av_strtod(p, &p); if (p && *p) p++;
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if (point->x < 0 || point->x > 1 || point->y < 0 || point->y > 1) {
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av_log(ctx, AV_LOG_ERROR, "Invalid key point coordinates (%f;%f), "
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"x and y must be in the [0;1] range.\n", point->x, point->y);
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return AVERROR(EINVAL);
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}
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if (!*points)
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*points = point;
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if (last) {
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if ((int)(last->x * 255) >= (int)(point->x * 255)) {
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av_log(ctx, AV_LOG_ERROR, "Key point coordinates (%f;%f) "
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"and (%f;%f) are too close from each other or not "
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"strictly increasing on the x-axis\n",
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last->x, last->y, point->x, point->y);
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return AVERROR(EINVAL);
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}
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last->next = point;
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}
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last = point;
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}
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/* auto insert first key point if missing at x=0 */
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if (!*points) {
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last = make_point(0, 0, NULL);
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if (!last)
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return AVERROR(ENOMEM);
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last->x = last->y = 0;
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*points = last;
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} else if ((*points)->x != 0.) {
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struct keypoint *newfirst = make_point(0, 0, *points);
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if (!newfirst)
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return AVERROR(ENOMEM);
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*points = newfirst;
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}
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av_assert0(last);
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/* auto insert last key point if missing at x=1 */
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if (last->x != 1.) {
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struct keypoint *point = make_point(1, 1, NULL);
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if (!point)
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return AVERROR(ENOMEM);
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last->next = point;
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}
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return 0;
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}
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static int get_nb_points(const struct keypoint *d)
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{
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int n = 0;
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while (d) {
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n++;
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d = d->next;
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}
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return n;
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}
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/**
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* Natural cubic spline interpolation
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* Finding curves using Cubic Splines notes by Steven Rauch and John Stockie.
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* @see http://people.math.sfu.ca/~stockie/teaching/macm316/notes/splines.pdf
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*/
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static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *points)
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{
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int i, ret = 0;
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const struct keypoint *point;
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double xprev = 0;
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int n = get_nb_points(points); // number of splines
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double (*matrix)[3] = av_calloc(n, sizeof(*matrix));
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double *h = av_malloc((n - 1) * sizeof(*h));
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double *r = av_calloc(n, sizeof(*r));
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if (!matrix || !h || !r) {
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ret = AVERROR(ENOMEM);
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goto end;
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}
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/* h(i) = x(i+1) - x(i) */
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i = -1;
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for (point = points; point; point = point->next) {
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if (i != -1)
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h[i] = point->x - xprev;
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xprev = point->x;
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i++;
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}
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/* right-side of the polynomials, will be modified to contains the solution */
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point = points;
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for (i = 1; i < n - 1; i++) {
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double yp = point->y,
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yc = point->next->y,
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yn = point->next->next->y;
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r[i] = 6 * ((yn-yc)/h[i] - (yc-yp)/h[i-1]);
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point = point->next;
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}
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#define B 0 /* sub diagonal (below main) */
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#define M 1 /* main diagonal (center) */
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#define A 2 /* sup diagonal (above main) */
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/* left side of the polynomials into a tridiagonal matrix. */
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matrix[0][M] = matrix[n - 1][M] = 1;
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for (i = 1; i < n - 1; i++) {
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matrix[i][B] = h[i-1];
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matrix[i][M] = 2 * (h[i-1] + h[i]);
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matrix[i][A] = h[i];
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}
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/* tridiagonal solving of the linear system */
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for (i = 1; i < n; i++) {
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double den = matrix[i][M] - matrix[i][B] * matrix[i-1][A];
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double k = den ? 1./den : 1.;
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matrix[i][A] *= k;
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r[i] = (r[i] - matrix[i][B] * r[i - 1]) * k;
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}
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for (i = n - 2; i >= 0; i--)
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r[i] = r[i] - matrix[i][A] * r[i + 1];
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/* compute the graph with x=[0..255] */
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i = 0;
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point = points;
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av_assert0(point->next); // always at least 2 key points
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while (point->next) {
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double yc = point->y;
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double yn = point->next->y;
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double a = yc;
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double b = (yn-yc)/h[i] - h[i]*r[i]/2. - h[i]*(r[i+1]-r[i])/6.;
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double c = r[i] / 2.;
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double d = (r[i+1] - r[i]) / (6.*h[i]);
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int x;
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int x_start = point->x * 255;
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int x_end = point->next->x * 255;
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av_assert0(x_start >= 0 && x_start <= 255 &&
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x_end >= 0 && x_end <= 255);
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for (x = x_start; x <= x_end; x++) {
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double xx = (x - x_start) * 1/255.;
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double yy = a + b*xx + c*xx*xx + d*xx*xx*xx;
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y[x] = av_clipf(yy, 0, 1) * 255;
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av_log(ctx, AV_LOG_DEBUG, "f(%f)=%f -> y[%d]=%d\n", xx, yy, x, y[x]);
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}
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point = point->next;
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i++;
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}
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end:
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av_free(matrix);
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av_free(h);
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av_free(r);
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return ret;
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}
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static av_cold int init(AVFilterContext *ctx, const char *args)
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{
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int i, j, ret;
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CurvesContext *curves = ctx->priv;
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struct keypoint *comp_points[NB_COMP] = {0};
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curves->class = &curves_class;
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av_opt_set_defaults(curves);
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if ((ret = av_set_options_string(curves, args, "=", ":")) < 0)
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return ret;
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for (i = 0; i < NB_COMP; i++) {
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ret = parse_points_str(ctx, comp_points + i, curves->comp_points_str[i]);
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if (ret < 0)
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return ret;
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ret = interpolate(ctx, curves->graph[i], comp_points[i]);
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if (ret < 0)
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return ret;
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}
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if (av_log_get_level() >= AV_LOG_VERBOSE) {
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for (i = 0; i < NB_COMP; i++) {
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struct keypoint *point = comp_points[i];
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av_log(ctx, AV_LOG_VERBOSE, "#%d points:", i);
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while (point) {
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av_log(ctx, AV_LOG_VERBOSE, " (%f;%f)", point->x, point->y);
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point = point->next;
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}
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av_log(ctx, AV_LOG_VERBOSE, "\n");
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av_log(ctx, AV_LOG_VERBOSE, "#%d values:", i);
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for (j = 0; j < 256; j++)
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av_log(ctx, AV_LOG_VERBOSE, " %02X", curves->graph[i][j]);
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av_log(ctx, AV_LOG_VERBOSE, "\n");
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}
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}
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for (i = 0; i < NB_COMP; i++) {
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struct keypoint *point = comp_points[i];
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while (point) {
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struct keypoint *next = point->next;
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av_free(point);
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point = next;
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}
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}
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av_opt_free(curves);
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return 0;
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}
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static int query_formats(AVFilterContext *ctx)
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{
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static const enum AVPixelFormat pix_fmts[] = {AV_PIX_FMT_RGB24, AV_PIX_FMT_NONE};
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ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
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return 0;
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}
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static int filter_frame(AVFilterLink *inlink, AVFrame *in)
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{
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int x, y, i, direct = 0;
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AVFilterContext *ctx = inlink->dst;
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CurvesContext *curves = ctx->priv;
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AVFilterLink *outlink = inlink->dst->outputs[0];
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AVFrame *out;
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uint8_t *dst;
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const uint8_t *src;
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if (av_frame_is_writable(in)) {
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direct = 1;
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out = in;
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} else {
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out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
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if (!out) {
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av_frame_free(&in);
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return AVERROR(ENOMEM);
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}
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av_frame_copy_props(out, in);
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}
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dst = out->data[0];
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src = in ->data[0];
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for (y = 0; y < inlink->h; y++) {
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uint8_t *dstp = dst;
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const uint8_t *srcp = src;
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for (x = 0; x < inlink->w; x++)
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for (i = 0; i < NB_COMP; i++, dstp++, srcp++)
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*dstp = curves->graph[i][*srcp];
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dst += out->linesize[0];
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src += in ->linesize[0];
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}
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if (!direct)
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av_frame_free(&in);
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|
||||
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,
|
||||
};
|
||||
Loading…
Reference in New Issue