/*
* Copyright (c) 2016 Clément Bœsch <u pkh me>
*
* 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
*/
/**
* @todo
* - SIMD for compute_safe_ssd_integral_image
* - SIMD for final weighted averaging
* - better automatic defaults? see "Parameters" @ http://www.ipol.im/pub/art/2011/bcm_nlm/
* - temporal support (probably doesn't need any displacement according to
* "Denoising image sequences does not require motion estimation")
* - Bayer pixel format support for at least raw photos? (DNG support would be
* handy here)
* - FATE test (probably needs visual threshold test mechanism due to the use
* of floats)
*/
#include "libavutil/avassert.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
struct weighted_avg {
double total_weight;
double sum;
};
#define WEIGHT_LUT_NBITS 9
#define WEIGHT_LUT_SIZE (1<<WEIGHT_LUT_NBITS)
typedef struct NLMeansContext {
const AVClass *class;
int nb_planes;
int chroma_w, chroma_h;
double pdiff_scale; // invert of the filtering parameter (sigma*10) squared
double sigma; // denoising strength
int patch_size, patch_hsize; // patch size and half size
int patch_size_uv, patch_hsize_uv; // patch size and half size for chroma planes
int research_size, research_hsize; // research size and half size
int research_size_uv, research_hsize_uv; // research size and half size for chroma planes
uint32_t *ii_orig; // integral image
uint32_t *ii; // integral image starting after the 0-line and 0-column
int ii_w, ii_h; // width and height of the integral image
int ii_lz_32; // linesize in 32-bit units of the integral image
struct weighted_avg *wa; // weighted average of every pixel
int wa_linesize; // linesize for wa in struct size unit
double weight_lut[WEIGHT_LUT_SIZE]; // lookup table mapping (scaled) patch differences to their associated weights
double pdiff_lut_scale; // scale factor for patch differences before looking into the LUT
int max_meaningful_diff; // maximum difference considered (if the patch difference is too high we ignore the pixel)
} NLMeansContext;
#define OFFSET(x) offsetof(NLMeansContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption nlmeans_options[] = {
{ "s", "denoising strength", OFFSET(sigma), AV_OPT_TYPE_DOUBLE, { .dbl = 1.0 }, 1.0, 30.0, FLAGS },
{ "p", "patch size", OFFSET(patch_size), AV_OPT_TYPE_INT, { .i64 = 3*2+1 }, 0, 99, FLAGS },
{ "pc", "patch size for chroma planes", OFFSET(patch_size_uv), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 99, FLAGS },
{ "r", "research window", OFFSET(research_size), AV_OPT_TYPE_INT, { .i64 = 7*2+1 }, 0, 99, FLAGS },
{ "rc", "research window for chroma planes", OFFSET(research_size_uv), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 99, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(nlmeans);
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
AV_PIX_FMT_YUVJ411P,
AV_PIX_FMT_GRAY8, AV_PIX_FMT_GBRP,
AV_PIX_FMT_NONE
};
AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
if (!fmts_list)
return AVERROR(ENOMEM);
return ff_set_common_formats(ctx, fmts_list);
}
/*
* M is a discrete map where every entry contains the sum of all the entries
* in the rectangle from the top-left origin of M to its coordinate. In the
* following schema, "i" contains the sum of the whole map:
*
* M = +----------+-----------------+----+
* | | | |
* | | | |
* | a| b| c|
* +----------+-----------------+----+
* | | | |
* | | | |
* | | X | |
* | | | |
* | d| e| f|
* +----------+-----------------+----+
* | | | |
* | g| h| i|
* +----------+-----------------+----+
*
* The sum of the X box can be calculated with:
* X = e-d-b+a
*
* See https://en.wikipedia.org/wiki/Summed_area_table
*
* The compute*_ssd functions compute the integral image M where every entry
* contains the sum of the squared difference of every corresponding pixels of
* two input planes of the same size as M.
*/
static inline int get_integral_patch_value(const uint32_t *ii, int ii_lz_32, int x, int y, int p)
{
const int e = ii[(y + p ) * ii_lz_32 + (x + p )];
const int d = ii[(y + p ) * ii_lz_32 + (x - p - 1)];
const int b = ii[(y - p - 1) * ii_lz_32 + (x + p )];
const int a = ii[(y - p - 1) * ii_lz_32 + (x - p - 1)];
return e - d - b + a;
}
/**
* Compute squared difference of the safe area (the zone where s1 and s2
* overlap). It is likely the largest integral zone, so it is interesting to do
* as little checks as possible; contrary to the unsafe version of this
* function, we do not need any clipping here.
*
* The line above dst and the column to its left are always readable.
*
* This C version computes the SSD integral image using a scalar accumulator,
* while for SIMD implementation it is likely more interesting to use the
* two-loops algorithm variant.
*/
static void compute_safe_ssd_integral_image_c(uint32_t *dst, int dst_linesize_32,
const uint8_t *s1, int linesize1,
const uint8_t *s2, int linesize2,
int w, int h)
{
int x, y;
for (y = 0; y < h; y++) {
uint32_t acc = dst[-1] - dst[-dst_linesize_32 - 1];
for (x = 0; x < w; x++) {
const int d = s1[x] - s2[x];
acc += d * d;
dst[x] = dst[-dst_linesize_32 + x] + acc;
}
s1 += linesize1;
s2 += linesize2;
dst += dst_linesize_32;
}
}
/**
* Compute squared difference of an unsafe area (the zone nor s1 nor s2 could
* be readable).
*
* On the other hand, the line above dst and the column to its left are always
* readable.
*
* There is little point in having this function SIMDified as it is likely too
* complex and only handle small portions of the image.
*
* @param dst integral image
* @param dst_linesize_32 integral image linesize (in 32-bit integers unit)
* @param startx integral starting x position
* @param starty integral starting y position
* @param src source plane buffer
* @param linesize source plane linesize
* @param offx source offsetting in x
* @param offy source offsetting in y
* @paran r absolute maximum source offsetting
* @param sw source width
* @param sh source height
* @param w width to compute
* @param h height to compute
*/
static inline void compute_unsafe_ssd_integral_image(uint32_t *dst, int dst_linesize_32,
int startx, int starty,
const uint8_t *src, int linesize,
int offx, int offy, int r, int sw, int sh,
int w, int h)
{
int x, y;
for (y = starty; y < starty + h; y++) {
uint32_t acc = dst[y*dst_linesize_32 + startx - 1] - dst[(y-1)*dst_linesize_32 + startx - 1];
const int s1y = av_clip(y - r, 0, sh - 1);
const int s2y = av_clip(y - (r + offy), 0, sh - 1);
for (x = startx; x < startx + w; x++) {
const int s1x = av_clip(x - r, 0, sw - 1);
const int s2x = av_clip(x - (r + offx), 0, sw - 1);
const uint8_t v1 = src[s1y*linesize + s1x];
const uint8_t v2 = src[s2y*linesize + s2x];
const int d = v1 - v2;
acc += d * d;
dst[y*dst_linesize_32 + x] = dst[(y-1)*dst_linesize_32 + x] + acc;
}
}
}
/*
* Compute the sum of squared difference integral image
* http://www.ipol.im/pub/art/2014/57/
* Integral Images for Block Matching - Gabriele Facciolo, Nicolas Limare, Enric Meinhardt-Llopis
*
* @param ii integral image of dimension (w+e*2) x (h+e*2) with
* an additional zeroed top line and column already
* "applied" to the pointer value
* @param ii_linesize_32 integral image linesize (in 32-bit integers unit)
* @param src source plane buffer
* @param linesize source plane linesize
* @param offx x-offsetting ranging in [-e;e]
* @param offy y-offsetting ranging in [-e;e]
* @param w source width
* @param h source height
* @param e research padding edge
*/
static void compute_ssd_integral_image(uint32_t *ii, int ii_linesize_32,
const uint8_t *src, int linesize, int offx, int offy,
int e, int w, int h)
{
// ii has a surrounding padding of thickness "e"
const int ii_w = w + e*2;
const int ii_h = h + e*2;
// we center the first source
const int s1x = e;
const int s1y = e;
// 2nd source is the frame with offsetting
const int s2x = e + offx;
const int s2y = e + offy;
// get the dimension of the overlapping rectangle where it is always safe
// to compare the 2 sources pixels
const int startx_safe = FFMAX(s1x, s2x);
const int starty_safe = FFMAX(s1y, s2y);
const int endx_safe = FFMIN(s1x + w, s2x + w);
const int endy_safe = FFMIN(s1y + h, s2y + h);
// top part where only one of s1 and s2 is still readable, or none at all
compute_unsafe_ssd_integral_image(ii, ii_linesize_32,
0, 0,
src, linesize,
offx, offy, e, w, h,
ii_w, starty_safe);
// fill the left column integral required to compute the central
// overlapping one
compute_unsafe_ssd_integral_image(ii, ii_linesize_32,
0, starty_safe,
src, linesize,
offx, offy, e, w, h,
startx_safe, endy_safe - starty_safe);
// main and safe part of the integral
av_assert1(startx_safe - s1x >= 0); av_assert1(startx_safe - s1x < w);
av_assert1(starty_safe - s1y >= 0); av_assert1(starty_safe - s1y < h);
av_assert1(startx_safe - s2x >= 0); av_assert1(startx_safe - s2x < w);
av_assert1(starty_safe - s2y >= 0); av_assert1(starty_safe - s2y < h);
compute_safe_ssd_integral_image_c(ii + starty_safe*ii_linesize_32 + startx_safe, ii_linesize_32,
src + (starty_safe - s1y) * linesize + (startx_safe - s1x), linesize,
src + (starty_safe - s2y) * linesize + (startx_safe - s2x), linesize,
endx_safe - startx_safe, endy_safe - starty_safe);
// right part of the integral
compute_unsafe_ssd_integral_image(ii, ii_linesize_32,
endx_safe, starty_safe,
src, linesize,
offx, offy, e, w, h,
ii_w - endx_safe, endy_safe - starty_safe);
// bottom part where only one of s1 and s2 is still readable, or none at all
compute_unsafe_ssd_integral_image(ii, ii_linesize_32,
0, endy_safe,
src, linesize,
offx, offy, e, w, h,
ii_w, ii_h - endy_safe);
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
NLMeansContext *s = ctx->priv;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
const int e = FFMAX(s->research_hsize, s->research_hsize_uv)
+ FFMAX(s->patch_hsize, s->patch_hsize_uv);
s->chroma_w = FF_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
s->chroma_h = FF_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
s->nb_planes = av_pix_fmt_count_planes(inlink->format);
/* Allocate the integral image with extra edges of thickness "e"
*
* +_+-------------------------------+
* |0|0000000000000000000000000000000|
* +-x-------------------------------+
* |0|\ ^ |
* |0| ii | e |
* |0| v |
* |0| +-----------------------+ |
* |0| | | |
* |0|<->| | |
* |0| e | | |
* |0| | | |
* |0| +-----------------------+ |
* |0| |
* |0| |
* |0| |
* +-+-------------------------------+
*/
s->ii_w = inlink->w + e*2;
s->ii_h = inlink->h + e*2;
// align to 4 the linesize, "+1" is for the space of the left 0-column
s->ii_lz_32 = FFALIGN(s->ii_w + 1, 4);
// "+1" is for the space of the top 0-line
s->ii_orig = av_mallocz_array(s->ii_h + 1, s->ii_lz_32 * sizeof(*s->ii_orig));
if (!s->ii_orig)
return AVERROR(ENOMEM);
// skip top 0-line and left 0-column
s->ii = s->ii_orig + s->ii_lz_32 + 1;
// allocate weighted average for every pixel
s->wa_linesize = inlink->w;
s->wa = av_malloc_array(s->wa_linesize, inlink->h * sizeof(*s->wa));
if (!s->wa)
return AVERROR(ENOMEM);
return 0;
}
struct thread_data {
const uint8_t *src;
int src_linesize;
int startx, starty;
int endx, endy;
const uint32_t *ii_start;
int p;
};
static int nlmeans_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
{
int x, y;
NLMeansContext *s = ctx->priv;
const struct thread_data *td = arg;
const uint8_t *src = td->src;
const int src_linesize = td->src_linesize;
const int process_h = td->endy - td->starty;
const int slice_start = (process_h * jobnr ) / nb_jobs;
const int slice_end = (process_h * (jobnr+1)) / nb_jobs;
const int starty = td->starty + slice_start;
const int endy = td->starty + slice_end;
for (y = starty; y < endy; y++) {
for (x = td->startx; x < td->endx; x++) {
const int patch_diff_sq = get_integral_patch_value(td->ii_start, s->ii_lz_32, x, y, td->p);
if (patch_diff_sq < s->max_meaningful_diff) {
struct weighted_avg *wa = &s->wa[y*s->wa_linesize + x];
const int weight_lut_idx = patch_diff_sq * s->pdiff_lut_scale;
const double weight = s->weight_lut[weight_lut_idx]; // exp(-patch_diff_sq * s->pdiff_scale)
wa->total_weight += weight;
wa->sum += weight * src[y*src_linesize + x];
}
}
}
return 0;
}
static int nlmeans_plane(AVFilterContext *ctx, int w, int h, int p, int r,
uint8_t *dst, int dst_linesize,
const uint8_t *src, int src_linesize)
{
int x, y;
int offx, offy;
NLMeansContext *s = ctx->priv;
/* patches center points cover the whole research window so the patches
* themselves overflow the research window */
const int e = r + p;
/* focus an integral pointer on the centered image (s1) */
const uint32_t *centered_ii = s->ii + e*s->ii_lz_32 + e;
memset(s->wa, 0, s->wa_linesize * h * sizeof(*s->wa));
for (offy = -r; offy <= r; offy++) {
for (offx = -r; offx <= r; offx++) {
if (offx || offy) {
struct thread_data td = {
.src = src + offy*src_linesize + offx,
.src_linesize = src_linesize,
.startx = FFMAX(0, -offx),
.starty = FFMAX(0, -offy),
.endx = FFMIN(w, w - offx),
.endy = FFMIN(h, h - offy),
.ii_start = centered_ii + offy*s->ii_lz_32 + offx,
.p = p,
};
compute_ssd_integral_image(s->ii, s->ii_lz_32,
src, src_linesize,
offx, offy, e, w, h);
ctx->internal->execute(ctx, nlmeans_slice, &td, NULL,
FFMIN(td.endy - td.starty, ff_filter_get_nb_threads(ctx)));
}
}
}
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
struct weighted_avg *wa = &s->wa[y*s->wa_linesize + x];
// Also weight the centered pixel
wa->total_weight += 1.0;
wa->sum += 1.0 * src[y*src_linesize + x];
dst[y*dst_linesize + x] = av_clip_uint8(wa->sum / wa->total_weight);
}
}
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
int i;
AVFilterContext *ctx = inlink->dst;
NLMeansContext *s = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
AVFrame *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
av_frame_copy_props(out, in);
for (i = 0; i < s->nb_planes; i++) {
const int w = i ? s->chroma_w : inlink->w;
const int h = i ? s->chroma_h : inlink->h;
const int p = i ? s->patch_hsize_uv : s->patch_hsize;
const int r = i ? s->research_hsize_uv : s->research_hsize;
nlmeans_plane(ctx, w, h, p, r,
out->data[i], out->linesize[i],
in->data[i], in->linesize[i]);
}
av_frame_free(&in);
return ff_filter_frame(outlink, out);
}
#define CHECK_ODD_FIELD(field, name) do { \
if (!(s->field & 1)) { \
s->field |= 1; \
av_log(ctx, AV_LOG_WARNING, name " size must be odd, " \
"setting it to %d\n", s->field); \
} \
} while (0)
static av_cold int init(AVFilterContext *ctx)
{
int i;
NLMeansContext *s = ctx->priv;
const double h = s->sigma * 10.;
s->pdiff_scale = 1. / (h * h);
s->max_meaningful_diff = -log(1/255.) / s->pdiff_scale;
s->pdiff_lut_scale = 1./s->max_meaningful_diff * WEIGHT_LUT_SIZE;
av_assert0((s->max_meaningful_diff - 1) * s->pdiff_lut_scale < FF_ARRAY_ELEMS(s->weight_lut));
for (i = 0; i < WEIGHT_LUT_SIZE; i++)
s->weight_lut[i] = exp(-i / s->pdiff_lut_scale * s->pdiff_scale);
CHECK_ODD_FIELD(research_size, "Luma research window");
CHECK_ODD_FIELD(patch_size, "Luma patch");
if (!s->research_size_uv) s->research_size_uv = s->research_size;
if (!s->patch_size_uv) s->patch_size_uv = s->patch_size;
CHECK_ODD_FIELD(research_size_uv, "Chroma research window");
CHECK_ODD_FIELD(patch_size_uv, "Chroma patch");
s->research_hsize = s->research_size / 2;
s->research_hsize_uv = s->research_size_uv / 2;
s->patch_hsize = s->patch_size / 2;
s->patch_hsize_uv = s->patch_size_uv / 2;
av_log(ctx, AV_LOG_INFO, "Research window: %dx%d / %dx%d, patch size: %dx%d / %dx%d\n",
s->research_size, s->research_size, s->research_size_uv, s->research_size_uv,
s->patch_size, s->patch_size, s->patch_size_uv, s->patch_size_uv);
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
NLMeansContext *s = ctx->priv;
av_freep(&s->ii_orig);
av_freep(&s->wa);
}
static const AVFilterPad nlmeans_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_input,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad nlmeans_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
AVFilter ff_vf_nlmeans = {
.name = "nlmeans",
.description = NULL_IF_CONFIG_SMALL("Non-local means denoiser."),
.priv_size = sizeof(NLMeansContext),
.init = init,
.uninit = uninit,
.query_formats = query_formats,
.inputs = nlmeans_inputs,
.outputs = nlmeans_outputs,
.priv_class = &nlmeans_class,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
};