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FFmpeg/libavfilter/vf_blurdetect.c

378 lines
12 KiB
C

/*
* Copyright (c) 2021 Thilo Borgmann <thilo.borgmann _at_ mail.de>
*
* 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
*/
/**
* @file
* No-reference blurdetect filter
*
* Implementing:
* Marziliano, Pina, et al. "A no-reference perceptual blur metric." Proceedings.
* International conference on image processing. Vol. 3. IEEE, 2002.
* https://infoscience.epfl.ch/record/111802/files/14%20A%20no-reference%20perceptual%20blur%20metric.pdf
*
* @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
*/
#include "libavutil/imgutils.h"
#include "libavutil/opt.h"
#include "libavutil/qsort.h"
#include "internal.h"
#include "edge_common.h"
static int comp(const float *a,const float *b)
{
return FFDIFFSIGN(*a, *b);
}
typedef struct BLRContext {
const AVClass *class;
int hsub, vsub;
int nb_planes;
float low, high;
uint8_t low_u8, high_u8;
int radius; // radius during local maxima detection
int block_pct; // percentage of "sharpest" blocks in the image to use for bluriness calculation
int block_width; // width for block abbreviation
int block_height; // height for block abbreviation
int planes; // number of planes to filter
double blur_total;
uint64_t nb_frames;
float *blks;
uint8_t *filterbuf;
uint8_t *tmpbuf;
uint16_t *gradients;
int8_t *directions;
} BLRContext;
#define OFFSET(x) offsetof(BLRContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption blurdetect_options[] = {
{ "high", "set high threshold", OFFSET(high), AV_OPT_TYPE_FLOAT, {.dbl=30/255.}, 0, 1, FLAGS },
{ "low", "set low threshold", OFFSET(low), AV_OPT_TYPE_FLOAT, {.dbl=15/255.}, 0, 1, FLAGS },
{ "radius", "search radius for maxima detection", OFFSET(radius), AV_OPT_TYPE_INT, {.i64=50}, 1, 100, FLAGS },
{ "block_pct", "block pooling threshold when calculating blurriness", OFFSET(block_pct), AV_OPT_TYPE_INT, {.i64=80}, 1, 100, FLAGS },
{ "block_width", "block size for block-based abbreviation of blurriness", OFFSET(block_width), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
{ "block_height", "block size for block-based abbreviation of blurriness", OFFSET(block_height), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
{ "planes", "set planes to filter", OFFSET(planes), AV_OPT_TYPE_INT, {.i64=1}, 0, 15, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(blurdetect);
static av_cold int blurdetect_init(AVFilterContext *ctx)
{
BLRContext *s = ctx->priv;
s->low_u8 = s->low * 255. + .5;
s->high_u8 = s->high * 255. + .5;
return 0;
}
static int blurdetect_config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
BLRContext *s = ctx->priv;
const int bufsize = inlink->w * inlink->h;
const AVPixFmtDescriptor *pix_desc;
pix_desc = av_pix_fmt_desc_get(inlink->format);
s->hsub = pix_desc->log2_chroma_w;
s->vsub = pix_desc->log2_chroma_h;
s->nb_planes = av_pix_fmt_count_planes(inlink->format);
if (s->block_width < 1 || s->block_height < 1) {
s->block_width = inlink->w;
s->block_height = inlink->h;
}
s->tmpbuf = av_malloc(bufsize);
s->filterbuf = av_malloc(bufsize);
s->gradients = av_calloc(bufsize, sizeof(*s->gradients));
s->directions = av_malloc(bufsize);
s->blks = av_calloc((inlink->w / s->block_width) * (inlink->h / s->block_height),
sizeof(*s->blks));
if (!s->tmpbuf || !s->filterbuf || !s->gradients || !s->directions || !s->blks)
return AVERROR(ENOMEM);
return 0;
}
// edge width is defined as the distance between surrounding maxima of the edge pixel
static float edge_width(BLRContext *blr, int i, int j, int8_t dir, int w, int h,
int edge, const uint8_t *src, int src_linesize)
{
float width = 0;
int dX, dY;
int sign;
int tmp;
int p1;
int p2;
int k, x, y;
int radius = blr->radius;
switch(dir) {
case DIRECTION_HORIZONTAL: dX = 1; dY = 0; break;
case DIRECTION_VERTICAL: dX = 0; dY = 1; break;
case DIRECTION_45UP: dX = 1; dY = -1; break;
case DIRECTION_45DOWN: dX = 1; dY = 1; break;
default: dX = 1; dY = 1; break;
}
// determines if search in direction dX/dY is looking for a maximum or minimum
sign = src[j * src_linesize + i] > src[(j - dY) * src_linesize + i - dX] ? 1 : -1;
// search in -(dX/dY) direction
for (k = 0; k < radius; k++) {
x = i - k*dX;
y = j - k*dY;
p1 = y * src_linesize + x;
x -= dX;
y -= dY;
p2 = y * src_linesize + x;
if (x < 0 || x >= w || y < 0 || y >= h)
return 0;
tmp = (src[p1] - src[p2]) * sign;
if (tmp <= 0) // local maximum found
break;
}
width += k;
// search in +(dX/dY) direction
for (k = 0; k < radius; k++) {
x = i + k * dX;
y = j + k * dY;
p1 = y * src_linesize + x;
x += dX;
y += dY;
p2 = y * src_linesize + x;
if (x < 0 || x >= w || y < 0 || y >= h)
return 0;
tmp = (src[p1] - src[p2]) * sign;
if (tmp >= 0) // local maximum found
break;
}
width += k;
// for 45 degree directions approximate edge width in pixel units: 0.7 ~= sqrt(2)/2
if (dir == DIRECTION_45UP || dir == DIRECTION_45DOWN)
width *= 0.7;
return width;
}
static float calculate_blur(BLRContext *s, int w, int h, int hsub, int vsub,
int8_t* dir, int dir_linesize,
uint8_t* dst, int dst_linesize,
uint8_t* src, int src_linesize)
{
float total_width = 0.0;
int block_count;
double block_total_width;
int i, j;
int blkcnt = 0;
float *blks = s->blks;
float block_pool_threshold = s->block_pct / 100.0;
int block_width = AV_CEIL_RSHIFT(s->block_width, hsub);
int block_height = AV_CEIL_RSHIFT(s->block_height, vsub);
int brows = h / block_height;
int bcols = w / block_width;
for (int blkj = 0; blkj < brows; blkj++) {
for (int blki = 0; blki < bcols; blki++) {
block_total_width = 0.0;
block_count = 0;
for (int inj = 0; inj < block_height; inj++) {
for (int ini = 0; ini < block_width; ini++) {
i = blki * block_width + ini;
j = blkj * block_height + inj;
if (dst[j * dst_linesize + i] > 0) {
float width = edge_width(s, i, j, dir[j*dir_linesize+i],
w, h, dst[j*dst_linesize+i],
src, src_linesize);
if (width > 0.001) { // throw away zeros
block_count++;
block_total_width += width;
}
}
}
}
// if not enough edge pixels in a block, consider it smooth
if (block_total_width >= 2 && block_count) {
blks[blkcnt] = block_total_width / block_count;
blkcnt++;
}
}
}
// simple block pooling by sorting and keeping the sharper blocks
AV_QSORT(blks, blkcnt, float, comp);
blkcnt = ceil(blkcnt * block_pool_threshold);
for (int i = 0; i < blkcnt; i++) {
total_width += blks[i];
}
return total_width / blkcnt;
}
static void set_meta(AVDictionary **metadata, const char *key, float d)
{
char value[128];
snprintf(value, sizeof(value), "%f", d);
av_dict_set(metadata, key, value, 0);
}
static int blurdetect_filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
BLRContext *s = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
const int inw = inlink->w;
const int inh = inlink->h;
uint8_t *tmpbuf = s->tmpbuf;
uint8_t *filterbuf = s->filterbuf;
uint16_t *gradients = s->gradients;
int8_t *directions = s->directions;
float blur = 0.0f;
int nplanes = 0;
AVDictionary **metadata;
metadata = &in->metadata;
for (int plane = 0; plane < s->nb_planes; plane++) {
int hsub = plane == 1 || plane == 2 ? s->hsub : 0;
int vsub = plane == 1 || plane == 2 ? s->vsub : 0;
int w = AV_CEIL_RSHIFT(inw, hsub);
int h = AV_CEIL_RSHIFT(inh, vsub);
if (!((1 << plane) & s->planes))
continue;
nplanes++;
// gaussian filter to reduce noise
ff_gaussian_blur_8(w, h,
filterbuf, w,
in->data[plane], in->linesize[plane], 1);
// compute the 16-bits gradients and directions for the next step
ff_sobel_8(w, h, gradients, w, directions, w, filterbuf, w, 1);
// non_maximum_suppression() will actually keep & clip what's necessary and
// ignore the rest, so we need a clean output buffer
memset(tmpbuf, 0, inw * inh);
ff_non_maximum_suppression(w, h, tmpbuf, w, directions, w, gradients, w);
// keep high values, or low values surrounded by high values
ff_double_threshold(s->low_u8, s->high_u8, w, h,
tmpbuf, w, tmpbuf, w);
blur += calculate_blur(s, w, h, hsub, vsub, directions, w,
tmpbuf, w, filterbuf, w);
}
if (nplanes)
blur /= nplanes;
s->blur_total += blur;
// write stats
av_log(ctx, AV_LOG_VERBOSE, "blur: %.7f\n", blur);
set_meta(metadata, "lavfi.blur", blur);
s->nb_frames = inlink->frame_count_in;
return ff_filter_frame(outlink, in);
}
static av_cold void blurdetect_uninit(AVFilterContext *ctx)
{
BLRContext *s = ctx->priv;
if (s->nb_frames > 0) {
av_log(ctx, AV_LOG_INFO, "blur mean: %.7f\n",
s->blur_total / s->nb_frames);
}
av_freep(&s->tmpbuf);
av_freep(&s->filterbuf);
av_freep(&s->gradients);
av_freep(&s->directions);
av_freep(&s->blks);
}
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_GRAY8,
AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P,
AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P,
AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P,
AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
AV_PIX_FMT_NONE
};
static const AVFilterPad blurdetect_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = blurdetect_config_input,
.filter_frame = blurdetect_filter_frame,
},
};
static const AVFilterPad blurdetect_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
};
const AVFilter ff_vf_blurdetect = {
.name = "blurdetect",
.description = NULL_IF_CONFIG_SMALL("Blurdetect filter."),
.priv_size = sizeof(BLRContext),
.init = blurdetect_init,
.uninit = blurdetect_uninit,
FILTER_PIXFMTS_ARRAY(pix_fmts),
FILTER_INPUTS(blurdetect_inputs),
FILTER_OUTPUTS(blurdetect_outputs),
.priv_class = &blurdetect_class,
.flags = AVFILTER_FLAG_METADATA_ONLY,
};