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FFmpeg/libavfilter/vf_photosensitivity.c

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/*
* Copyright (c) 2019 Vladimir Panteleev
*
* 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 <float.h>
#include "libavutil/opt.h"
#include "avfilter.h"
#include "filters.h"
#include "internal.h"
#include "video.h"
#define MAX_FRAMES 240
#define GRID_SIZE 8
#define NUM_CHANNELS 3
typedef struct PhotosensitivityFrame {
uint8_t grid[GRID_SIZE][GRID_SIZE][4];
} PhotosensitivityFrame;
typedef struct PhotosensitivityContext {
const AVClass *class;
int nb_frames;
int skip;
float threshold_multiplier;
int bypass;
int badness_threshold;
/* Circular buffer */
int history[MAX_FRAMES];
int history_pos;
PhotosensitivityFrame last_frame_e;
AVFrame *last_frame_av;
} PhotosensitivityContext;
#define OFFSET(x) offsetof(PhotosensitivityContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption photosensitivity_options[] = {
{ "frames", "set how many frames to use", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.i64=30}, 2, MAX_FRAMES, FLAGS },
{ "f", "set how many frames to use", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.i64=30}, 2, MAX_FRAMES, FLAGS },
{ "threshold", "set detection threshold factor (lower is stricter)", OFFSET(threshold_multiplier), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0.1, FLT_MAX, FLAGS },
{ "t", "set detection threshold factor (lower is stricter)", OFFSET(threshold_multiplier), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0.1, FLT_MAX, FLAGS },
{ "skip", "set pixels to skip when sampling frames", OFFSET(skip), AV_OPT_TYPE_INT, {.i64=1}, 1, 1024, FLAGS },
{ "bypass", "leave frames unchanged", OFFSET(bypass), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(photosensitivity);
typedef struct ThreadData_convert_frame
{
AVFrame *in;
PhotosensitivityFrame *out;
int skip;
} ThreadData_convert_frame;
#define NUM_CELLS (GRID_SIZE * GRID_SIZE)
static int convert_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
{
int cell, gx, gy, x0, x1, y0, y1, x, y, c, area;
int sum[NUM_CHANNELS];
const uint8_t *p;
ThreadData_convert_frame *td = arg;
const int slice_start = (NUM_CELLS * jobnr) / nb_jobs;
const int slice_end = (NUM_CELLS * (jobnr+1)) / nb_jobs;
int width = td->in->width, height = td->in->height, linesize = td->in->linesize[0], skip = td->skip;
const uint8_t *data = td->in->data[0];
for (cell = slice_start; cell < slice_end; cell++) {
gx = cell % GRID_SIZE;
gy = cell / GRID_SIZE;
x0 = width * gx / GRID_SIZE;
x1 = width * (gx+1) / GRID_SIZE;
y0 = height * gy / GRID_SIZE;
y1 = height * (gy+1) / GRID_SIZE;
for (c = 0; c < NUM_CHANNELS; c++) {
sum[c] = 0;
}
for (y = y0; y < y1; y += skip) {
p = data + y * linesize + x0 * NUM_CHANNELS;
for (x = x0; x < x1; x += skip) {
//av_log(NULL, AV_LOG_VERBOSE, "%d %d %d : (%d,%d) (%d,%d) -> %d,%d | *%d\n", c, gx, gy, x0, y0, x1, y1, x, y, (int)row);
sum[0] += p[0];
sum[1] += p[1];
sum[2] += p[2];
p += NUM_CHANNELS * skip;
// TODO: variable size
}
}
area = ((x1 - x0 + skip - 1) / skip) * ((y1 - y0 + skip - 1) / skip);
for (c = 0; c < NUM_CHANNELS; c++) {
if (area)
sum[c] /= area;
td->out->grid[gy][gx][c] = sum[c];
}
}
return 0;
}
static void convert_frame(AVFilterContext *ctx, AVFrame *in, PhotosensitivityFrame *out, int skip)
{
ThreadData_convert_frame td;
td.in = in;
td.out = out;
td.skip = skip;
ff_filter_execute(ctx, convert_frame_partial, &td, NULL,
FFMIN(NUM_CELLS, ff_filter_get_nb_threads(ctx)));
}
typedef struct ThreadData_blend_frame
{
AVFrame *target;
AVFrame *source;
uint16_t s_mul;
} ThreadData_blend_frame;
static int blend_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
{
int x, y;
uint8_t *t, *s;
ThreadData_blend_frame *td = arg;
const uint16_t s_mul = td->s_mul;
const uint16_t t_mul = 0x100 - s_mul;
const int slice_start = (td->target->height * jobnr) / nb_jobs;
const int slice_end = (td->target->height * (jobnr+1)) / nb_jobs;
const int linesize = td->target->linesize[0];
for (y = slice_start; y < slice_end; y++) {
t = td->target->data[0] + y * td->target->linesize[0];
s = td->source->data[0] + y * td->source->linesize[0];
for (x = 0; x < linesize; x++) {
*t = (*t * t_mul + *s * s_mul) >> 8;
t++; s++;
}
}
return 0;
}
static void blend_frame(AVFilterContext *ctx, AVFrame *target, AVFrame *source, float factor)
{
ThreadData_blend_frame td;
td.target = target;
td.source = source;
td.s_mul = (uint16_t)(factor * 0x100);
ff_filter_execute(ctx, blend_frame_partial, &td, NULL,
FFMIN(ctx->outputs[0]->h, ff_filter_get_nb_threads(ctx)));
}
static int get_badness(PhotosensitivityFrame *a, PhotosensitivityFrame *b)
{
int badness, x, y, c;
badness = 0;
for (c = 0; c < NUM_CHANNELS; c++) {
for (y = 0; y < GRID_SIZE; y++) {
for (x = 0; x < GRID_SIZE; x++) {
badness += abs((int)a->grid[y][x][c] - (int)b->grid[y][x][c]);
//av_log(NULL, AV_LOG_VERBOSE, "%d - %d -> %d \n", a->grid[y][x], b->grid[y][x], badness);
//av_log(NULL, AV_LOG_VERBOSE, "%d -> %d \n", abs((int)a->grid[y][x] - (int)b->grid[y][x]), badness);
}
}
}
return badness;
}
static int config_input(AVFilterLink *inlink)
{
/* const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format); */
AVFilterContext *ctx = inlink->dst;
PhotosensitivityContext *s = ctx->priv;
s->badness_threshold = (int)(GRID_SIZE * GRID_SIZE * 4 * 256 * s->nb_frames * s->threshold_multiplier / 128);
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
int this_badness, current_badness, fixed_badness, new_badness, i, res;
PhotosensitivityFrame ef;
AVFrame *src, *out;
int free_in = 0;
float factor;
AVDictionary **metadata;
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
PhotosensitivityContext *s = ctx->priv;
/* weighted moving average */
current_badness = 0;
for (i = 1; i < s->nb_frames; i++)
current_badness += i * s->history[(s->history_pos + i) % s->nb_frames];
current_badness /= s->nb_frames;
convert_frame(ctx, in, &ef, s->skip);
this_badness = get_badness(&ef, &s->last_frame_e);
new_badness = current_badness + this_badness;
av_log(s, AV_LOG_VERBOSE, "badness: %6d -> %6d / %6d (%3d%% - %s)\n",
current_badness, new_badness, s->badness_threshold,
100 * new_badness / s->badness_threshold, new_badness < s->badness_threshold ? "OK" : "EXCEEDED");
fixed_badness = new_badness;
if (new_badness < s->badness_threshold || !s->last_frame_av || s->bypass) {
factor = 1; /* for metadata */
av_frame_free(&s->last_frame_av);
s->last_frame_av = src = in;
s->last_frame_e = ef;
s->history[s->history_pos] = this_badness;
} else {
factor = (float)(s->badness_threshold - current_badness) / (new_badness - current_badness);
if (factor <= 0) {
/* just duplicate the frame */
s->history[s->history_pos] = 0; /* frame was duplicated, thus, delta is zero */
} else {
res = ff_inlink_make_frame_writable(inlink, &s->last_frame_av);
if (res) {
av_frame_free(&in);
return res;
}
blend_frame(ctx, s->last_frame_av, in, factor);
convert_frame(ctx, s->last_frame_av, &ef, s->skip);
this_badness = get_badness(&ef, &s->last_frame_e);
fixed_badness = current_badness + this_badness;
av_log(s, AV_LOG_VERBOSE, " fixed: %6d -> %6d / %6d (%3d%%) factor=%5.3f\n",
current_badness, fixed_badness, s->badness_threshold,
100 * new_badness / s->badness_threshold, factor);
s->last_frame_e = ef;
s->history[s->history_pos] = this_badness;
}
src = s->last_frame_av;
free_in = 1;
}
s->history_pos = (s->history_pos + 1) % s->nb_frames;
out = ff_get_video_buffer(outlink, in->width, in->height);
if (!out) {
if (free_in == 1)
av_frame_free(&in);
return AVERROR(ENOMEM);
}
av_frame_copy_props(out, in);
metadata = &out->metadata;
if (metadata) {
char value[128];
snprintf(value, sizeof(value), "%f", (float)new_badness / s->badness_threshold);
av_dict_set(metadata, "lavfi.photosensitivity.badness", value, 0);
snprintf(value, sizeof(value), "%f", (float)fixed_badness / s->badness_threshold);
av_dict_set(metadata, "lavfi.photosensitivity.fixed-badness", value, 0);
snprintf(value, sizeof(value), "%f", (float)this_badness / s->badness_threshold);
av_dict_set(metadata, "lavfi.photosensitivity.frame-badness", value, 0);
snprintf(value, sizeof(value), "%f", factor);
av_dict_set(metadata, "lavfi.photosensitivity.factor", value, 0);
}
av_frame_copy(out, src);
if (free_in == 1)
av_frame_free(&in);
return ff_filter_frame(outlink, out);
}
static av_cold void uninit(AVFilterContext *ctx)
{
PhotosensitivityContext *s = ctx->priv;
av_frame_free(&s->last_frame_av);
}
static const AVFilterPad inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.config_props = config_input,
},
};
const AVFilter ff_vf_photosensitivity = {
.name = "photosensitivity",
.description = NULL_IF_CONFIG_SMALL("Filter out photosensitive epilepsy seizure-inducing flashes."),
.priv_size = sizeof(PhotosensitivityContext),
.priv_class = &photosensitivity_class,
.uninit = uninit,
2021-08-12 13:05:31 +02:00
FILTER_INPUTS(inputs),
FILTER_OUTPUTS(ff_video_default_filterpad),
FILTER_PIXFMTS(AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24),
};