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/*
* Copyright (c) 2015 Timo Rothenpieler <timo@rothenpieler.org>
*
* 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/imgutils.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
typedef struct ColorkeyContext {
const AVClass *class;
/* color offsets rgba */
int co[4];
uint8_t colorkey_rgba[4];
float similarity;
float blend;
} ColorkeyContext;
static uint8_t do_colorkey_pixel(ColorkeyContext *ctx, uint8_t r, uint8_t g, uint8_t b)
{
int dr = (int)r - ctx->colorkey_rgba[0];
int dg = (int)g - ctx->colorkey_rgba[1];
int db = (int)b - ctx->colorkey_rgba[2];
double diff = sqrt((dr * dr + dg * dg + db * db) / (255.0 * 255.0));
if (ctx->blend > 0.0001) {
return av_clipd((diff - ctx->similarity) / ctx->blend, 0.0, 1.0) * 255.0;
} else {
return (diff > ctx->similarity) ? 255 : 0;
}
}
static int do_colorkey_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
{
AVFrame *frame = arg;
const int slice_start = (frame->height * jobnr) / nb_jobs;
const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
ColorkeyContext *ctx = avctx->priv;
int o, x, y;
for (y = slice_start; y < slice_end; ++y) {
for (x = 0; x < frame->width; ++x) {
o = frame->linesize[0] * y + x * 4;
frame->data[0][o + ctx->co[3]] =
do_colorkey_pixel(ctx,
frame->data[0][o + ctx->co[0]],
frame->data[0][o + ctx->co[1]],
frame->data[0][o + ctx->co[2]]);
}
}
return 0;
}
static int filter_frame(AVFilterLink *link, AVFrame *frame)
{
AVFilterContext *avctx = link->dst;
int res;
if (res = av_frame_make_writable(frame))
return res;
if (res = avctx->internal->execute(avctx, do_colorkey_slice, frame, NULL, FFMIN(frame->height, ff_filter_get_nb_threads(avctx))))
return res;
return ff_filter_frame(avctx->outputs[0], frame);
}
static av_cold int config_output(AVFilterLink *outlink)
{
AVFilterContext *avctx = outlink->src;
ColorkeyContext *ctx = avctx->priv;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
int i;
outlink->w = avctx->inputs[0]->w;
outlink->h = avctx->inputs[0]->h;
outlink->time_base = avctx->inputs[0]->time_base;
for (i = 0; i < 4; ++i)
ctx->co[i] = desc->comp[i].offset;
return 0;
}
static av_cold int query_formats(AVFilterContext *avctx)
{
static const enum AVPixelFormat pixel_fmts[] = {
AV_PIX_FMT_ARGB,
AV_PIX_FMT_RGBA,
AV_PIX_FMT_ABGR,
AV_PIX_FMT_BGRA,
AV_PIX_FMT_NONE
};
AVFilterFormats *formats = NULL;
formats = ff_make_format_list(pixel_fmts);
if (!formats)
return AVERROR(ENOMEM);
return ff_set_common_formats(avctx, formats);
}
static const AVFilterPad colorkey_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad colorkey_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_output,
},
{ NULL }
};
#define OFFSET(x) offsetof(ColorkeyContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption colorkey_options[] = {
{ "color", "set the colorkey key color", OFFSET(colorkey_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
{ "similarity", "set the colorkey similarity value", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
{ "blend", "set the colorkey key blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(colorkey);
AVFilter ff_vf_colorkey = {
.name = "colorkey",
.description = NULL_IF_CONFIG_SMALL("Turns a certain color into transparency. Operates on RGB colors."),
.priv_size = sizeof(ColorkeyContext),
.priv_class = &colorkey_class,
.query_formats = query_formats,
.inputs = colorkey_inputs,
.outputs = colorkey_outputs,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
};
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