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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 ChromakeyContext {
const AVClass *class;
uint8_t chromakey_rgba[4];
uint8_t chromakey_uv[2];
float similarity;
float blend;
int is_yuv;
int hsub_log2;
int vsub_log2;
} ChromakeyContext;
static uint8_t do_chromakey_pixel(ChromakeyContext *ctx, uint8_t u[9], uint8_t v[9])
{
double diff = 0.0;
int du, dv, i;
for (i = 0; i < 9; ++i) {
du = (int)u[i] - ctx->chromakey_uv[0];
dv = (int)v[i] - ctx->chromakey_uv[1];
diff += sqrt((du * du + dv * dv) / (255.0 * 255.0));
}
diff /= 9.0;
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 av_always_inline void get_pixel_uv(AVFrame *frame, int hsub_log2, int vsub_log2, int x, int y, uint8_t *u, uint8_t *v)
{
if (x < 0 || x >= frame->width || y < 0 || y >= frame->height)
return;
x >>= hsub_log2;
y >>= vsub_log2;
*u = frame->data[1][frame->linesize[1] * y + x];
*v = frame->data[2][frame->linesize[2] * y + x];
}
static int do_chromakey_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;
ChromakeyContext *ctx = avctx->priv;
int x, y, xo, yo;
uint8_t u[9], v[9];
memset(u, ctx->chromakey_uv[0], sizeof(u));
memset(v, ctx->chromakey_uv[1], sizeof(v));
for (y = slice_start; y < slice_end; ++y) {
for (x = 0; x < frame->width; ++x) {
for (yo = 0; yo < 3; ++yo) {
for (xo = 0; xo < 3; ++xo) {
get_pixel_uv(frame, ctx->hsub_log2, ctx->vsub_log2, x + xo - 1, y + yo - 1, &u[yo * 3 + xo], &v[yo * 3 + xo]);
}
}
frame->data[3][frame->linesize[3] * y + x] = do_chromakey_pixel(ctx, u, v);
}
}
return 0;
}
static int filter_frame(AVFilterLink *link, AVFrame *frame)
{
AVFilterContext *avctx = link->dst;
int res;
if (res = avctx->internal->execute(avctx, do_chromakey_slice, frame, NULL, FFMIN(frame->height, avctx->graph->nb_threads)))
return res;
return ff_filter_frame(avctx->outputs[0], frame);
}
#define FIXNUM(x) lrint((x) * (1 << 10))
#define RGB_TO_U(rgb) (((- FIXNUM(0.16874) * rgb[0] - FIXNUM(0.33126) * rgb[1] + FIXNUM(0.50000) * rgb[2] + (1 << 9) - 1) >> 10) + 128)
#define RGB_TO_V(rgb) ((( FIXNUM(0.50000) * rgb[0] - FIXNUM(0.41869) * rgb[1] - FIXNUM(0.08131) * rgb[2] + (1 << 9) - 1) >> 10) + 128)
static av_cold int initialize_chromakey(AVFilterContext *avctx)
{
ChromakeyContext *ctx = avctx->priv;
if (ctx->is_yuv) {
ctx->chromakey_uv[0] = ctx->chromakey_rgba[1];
ctx->chromakey_uv[1] = ctx->chromakey_rgba[2];
} else {
ctx->chromakey_uv[0] = RGB_TO_U(ctx->chromakey_rgba);
ctx->chromakey_uv[1] = RGB_TO_V(ctx->chromakey_rgba);
}
return 0;
}
static av_cold int query_formats(AVFilterContext *avctx)
{
static const enum AVPixelFormat pixel_fmts[] = {
AV_PIX_FMT_YUVA420P,
AV_PIX_FMT_YUVA422P,
AV_PIX_FMT_YUVA444P,
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 av_cold int config_input(AVFilterLink *inlink)
{
AVFilterContext *avctx = inlink->dst;
ChromakeyContext *ctx = avctx->priv;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
ctx->hsub_log2 = desc->log2_chroma_w;
ctx->vsub_log2 = desc->log2_chroma_h;
return 0;
}
static const AVFilterPad chromakey_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.needs_writable = 1,
.filter_frame = filter_frame,
.config_props = config_input,
},
{ NULL }
};
static const AVFilterPad chromakey_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
#define OFFSET(x) offsetof(ChromakeyContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption chromakey_options[] = {
{ "color", "set the chromakey key color", OFFSET(chromakey_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
{ "similarity", "set the chromakey similarity value", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
{ "blend", "set the chromakey key blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
{ "yuv", "color parameter is in yuv instead of rgb", OFFSET(is_yuv), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(chromakey);
AVFilter ff_vf_chromakey = {
.name = "chromakey",
.description = NULL_IF_CONFIG_SMALL("Turns a certain color into transparency. Operates on YUV colors."),
.priv_size = sizeof(ChromakeyContext),
.priv_class = &chromakey_class,
.init = initialize_chromakey,
.query_formats = query_formats,
.inputs = chromakey_inputs,
.outputs = chromakey_outputs,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
};
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