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FFmpeg/libavfilter/vf_backgroundkey.c
2022-11-05 10:52:39 +01:00

256 lines
8.8 KiB
C

/*
* 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 BackgroundkeyContext {
const AVClass *class;
float threshold;
float similarity;
float blend;
int max;
int nb_threads;
int hsub_log2;
int vsub_log2;
int64_t max_sum;
int64_t *sums;
AVFrame *background;
int (*do_slice)(AVFilterContext *avctx, void *arg,
int jobnr, int nb_jobs);
} BackgroundkeyContext;
static int do_backgroundkey_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
{
BackgroundkeyContext *s = avctx->priv;
AVFrame *frame = arg;
const int slice_start = (frame->height * jobnr) / nb_jobs;
const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
const int min_diff = (255 + 255 + 255) * s->similarity;
const float blend = s->blend;
const int hsub = s->hsub_log2;
const int vsub = s->vsub_log2;
int64_t sum = 0;
for (int y = slice_start; y < slice_end; y++) {
const uint8_t *srcy = frame->data[0] + frame->linesize[0] * y;
const uint8_t *srcu = frame->data[1] + frame->linesize[1] * (y >> vsub);
const uint8_t *srcv = frame->data[2] + frame->linesize[2] * (y >> vsub);
const uint8_t *bsrcy = s->background->data[0] + s->background->linesize[0] * y;
const uint8_t *bsrcu = s->background->data[1] + s->background->linesize[1] * (y >> vsub);
const uint8_t *bsrcv = s->background->data[2] + s->background->linesize[2] * (y >> vsub);
uint8_t *dst = frame->data[3] + frame->linesize[3] * y;
for (int x = 0; x < frame->width; x++) {
const int xx = x >> hsub;
const int diff = FFABS(srcy[x] - bsrcy[x]) +
FFABS(srcu[xx] - bsrcu[xx]) +
FFABS(srcv[xx] - bsrcv[xx]);
int A;
sum += diff;
if (blend > 0.f) {
A = 255 - av_clipf((min_diff - diff) / blend, 0.f, 255.f);
} else {
A = (diff > min_diff) ? 255 : 0;
}
dst[x] = A;
}
}
s->sums[jobnr] = sum;
return 0;
}
static int do_backgroundkey16_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
{
BackgroundkeyContext *s = avctx->priv;
AVFrame *frame = arg;
const int slice_start = (frame->height * jobnr) / nb_jobs;
const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
const int hsub = s->hsub_log2;
const int vsub = s->vsub_log2;
const int max = s->max;
const int min_diff = s->similarity * (s->max + s->max + s->max);
const float blend = s->blend;
int64_t sum = 0;
for (int y = slice_start; y < slice_end; y++) {
const uint16_t *srcy = (const uint16_t *)(frame->data[0] + frame->linesize[0] * y);
const uint16_t *srcu = (const uint16_t *)(frame->data[1] + frame->linesize[1] * (y >> vsub));
const uint16_t *srcv = (const uint16_t *)(frame->data[2] + frame->linesize[2] * (y >> vsub));
const uint16_t *bsrcy = (const uint16_t *)(s->background->data[0] + s->background->linesize[0] * y);
const uint16_t *bsrcu = (const uint16_t *)(s->background->data[1] + s->background->linesize[1] * (y >> vsub));
const uint16_t *bsrcv = (const uint16_t *)(s->background->data[2] + s->background->linesize[2] * (y >> vsub));
uint16_t *dst = (uint16_t *)(frame->data[3] + frame->linesize[3] * y);
for (int x = 0; x < frame->width; x++) {
const int xx = x >> hsub;
const int diff = FFABS(srcy[x] - bsrcy[x] ) +
FFABS(srcu[xx] - bsrcu[xx]) +
FFABS(srcv[xx] - bsrcv[xx]);
int A;
sum += diff;
if (blend > 0.f) {
A = max - av_clipf((min_diff - diff) / blend, 0.f, max);
} else {
A = (diff > min_diff) ? max : 0;
}
dst[x] = A;
}
}
s->sums[jobnr] = sum;
return 0;
}
static int filter_frame(AVFilterLink *link, AVFrame *frame)
{
AVFilterContext *avctx = link->dst;
BackgroundkeyContext *s = avctx->priv;
int64_t sum = 0;
int ret = 0;
if (!s->background) {
s->background = ff_get_video_buffer(link, frame->width, frame->height);
if (!s->background) {
ret = AVERROR(ENOMEM);
goto fail;
}
ret = av_frame_copy(s->background, frame);
if (ret < 0)
goto fail;
}
if (ret = ff_filter_execute(avctx, s->do_slice, frame, NULL,
FFMIN(frame->height, s->nb_threads)))
goto fail;
for (int n = 0; n < s->nb_threads; n++)
sum += s->sums[n];
if (s->max_sum * s->threshold < sum) {
ret = av_frame_copy(s->background, frame);
if (ret < 0)
goto fail;
}
return ff_filter_frame(avctx->outputs[0], frame);
fail:
av_frame_free(&frame);
return ret;
}
static av_cold int config_output(AVFilterLink *outlink)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
AVFilterContext *avctx = outlink->src;
AVFilterLink *inlink = avctx->inputs[0];
BackgroundkeyContext *s = avctx->priv;
int depth;
s->nb_threads = ff_filter_get_nb_threads(avctx);
depth = desc->comp[0].depth;
s->do_slice = depth <= 8 ? do_backgroundkey_slice : do_backgroundkey16_slice;
s->max = (1 << depth) - 1;
s->hsub_log2 = desc->log2_chroma_w;
s->vsub_log2 = desc->log2_chroma_h;
s->max_sum = (int64_t)(inlink->w) * inlink->h * s->max;
s->max_sum += 2LL * (inlink->w >> s->hsub_log2) * (inlink->h >> s->vsub_log2) * s->max;
s->sums = av_calloc(s->nb_threads, sizeof(*s->sums));
if (!s->sums)
return AVERROR(ENOMEM);
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
BackgroundkeyContext *s = ctx->priv;
av_frame_free(&s->background);
av_freep(&s->sums);
}
static const AVFilterPad backgroundkey_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.flags = AVFILTERPAD_FLAG_NEEDS_WRITABLE,
.filter_frame = filter_frame,
},
};
static const AVFilterPad backgroundkey_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_output,
},
};
#define OFFSET(x) offsetof(BackgroundkeyContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
static const AVOption backgroundkey_options[] = {
{ "threshold", "set the scene change threshold", OFFSET(threshold), AV_OPT_TYPE_FLOAT, { .dbl = 0.08}, 0.0, 1.0, FLAGS },
{ "similarity", "set the similarity", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.1 }, 0.0, 1.0, FLAGS },
{ "blend", "set the blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
{ NULL }
};
static const enum AVPixelFormat backgroundkey_fmts[] = {
AV_PIX_FMT_YUVA420P,
AV_PIX_FMT_YUVA422P,
AV_PIX_FMT_YUVA444P,
AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,
AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA444P12,
AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
AV_PIX_FMT_GBRAP,
AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16,
AV_PIX_FMT_NONE
};
AVFILTER_DEFINE_CLASS(backgroundkey);
const AVFilter ff_vf_backgroundkey = {
.name = "backgroundkey",
.description = NULL_IF_CONFIG_SMALL("Turns a static background into transparency."),
.priv_size = sizeof(BackgroundkeyContext),
.priv_class = &backgroundkey_class,
.uninit = uninit,
FILTER_INPUTS(backgroundkey_inputs),
FILTER_OUTPUTS(backgroundkey_outputs),
FILTER_PIXFMTS_ARRAY(backgroundkey_fmts),
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
.process_command = ff_filter_process_command,
};