/*
* Copyright (c) 2013 Clément Bœsch
*
* 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
*/
/**
* A simple, relatively efficient and extremely slow DCT image denoiser.
* @see http://www.ipol.im/pub/art/2011/ys-dct/
*/
#include "libavcodec/avfft.h"
#include "libavutil/eval.h"
#include "libavutil/opt.h"
#include "drawutils.h"
#include "internal.h"
#define NBITS 4
#define BSIZE (1<<(NBITS))
static const char *const var_names[] = { "c", NULL };
enum { VAR_C, VAR_VARS_NB };
typedef struct {
const AVClass *class;
/* coefficient factor expression */
char *expr_str;
AVExpr *expr;
double var_values[VAR_VARS_NB];
int pr_width, pr_height; // width and height to process
float sigma; // used when no expression are st
float th; // threshold (3*sigma)
float color_dct[3][3]; // 3x3 DCT for color decorrelation
float *cbuf[2][3]; // two planar rgb color buffers
float *weights; // dct coeff are cumulated with overlapping; these values are used for averaging
int p_linesize; // line sizes for color and weights
int overlap; // number of block overlapping pixels
int step; // block step increment (BSIZE - overlap)
DCTContext *dct, *idct; // DCT and inverse DCT contexts
float *block, *tmp_block; // two BSIZE x BSIZE block buffers
} DCTdnoizContext;
#define OFFSET(x) offsetof(DCTdnoizContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption dctdnoiz_options[] = {
{ "sigma", "set noise sigma constant", OFFSET(sigma), AV_OPT_TYPE_FLOAT, {.dbl=0}, 0, 999, .flags = FLAGS },
{ "s", "set noise sigma constant", OFFSET(sigma), AV_OPT_TYPE_FLOAT, {.dbl=0}, 0, 999, .flags = FLAGS },
{ "overlap", "set number of block overlapping pixels", OFFSET(overlap), AV_OPT_TYPE_INT, {.i64=(1<<NBITS)-1}, 0, (1<<NBITS)-1, .flags = FLAGS },
{ "expr", "set coefficient factor expression", OFFSET(expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "e", "set coefficient factor expression", OFFSET(expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(dctdnoiz);
static float *dct_block(DCTdnoizContext *ctx, const float *src, int src_linesize)
{
int x, y;
float *column;
for (y = 0; y < BSIZE; y++) {
float *line = ctx->block;
memcpy(line, src, BSIZE * sizeof(*line));
src += src_linesize;
av_dct_calc(ctx->dct, line);
column = ctx->tmp_block + y;
column[0] = line[0] * (1. / sqrt(BSIZE));
column += BSIZE;
for (x = 1; x < BSIZE; x++) {
*column = line[x] * sqrt(2. / BSIZE);
column += BSIZE;
}
}
column = ctx->tmp_block;
for (x = 0; x < BSIZE; x++) {
av_dct_calc(ctx->dct, column);
column[0] *= 1. / sqrt(BSIZE);
for (y = 1; y < BSIZE; y++)
column[y] *= sqrt(2. / BSIZE);
column += BSIZE;
}
for (y = 0; y < BSIZE; y++)
for (x = 0; x < BSIZE; x++)
ctx->block[y*BSIZE + x] = ctx->tmp_block[x*BSIZE + y];
return ctx->block;
}
static void idct_block(DCTdnoizContext *ctx, float *dst, int dst_linesize)
{
int x, y;
float *block = ctx->block;
float *tmp = ctx->tmp_block;
for (y = 0; y < BSIZE; y++) {
block[0] *= sqrt(BSIZE);
for (x = 1; x < BSIZE; x++)
block[x] *= 1./sqrt(2. / BSIZE);
av_dct_calc(ctx->idct, block);
block += BSIZE;
}
block = ctx->block;
for (y = 0; y < BSIZE; y++) {
tmp[0] = block[y] * sqrt(BSIZE);
for (x = 1; x < BSIZE; x++)
tmp[x] = block[x*BSIZE + y] * (1./sqrt(2. / BSIZE));
av_dct_calc(ctx->idct, tmp);
for (x = 0; x < BSIZE; x++)
dst[x*dst_linesize + y] += tmp[x];
}
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
DCTdnoizContext *s = ctx->priv;
int i, x, y, bx, by, linesize, *iweights;
const float dct_3x3[3][3] = {
{ 1./sqrt(3), 1./sqrt(3), 1./sqrt(3) },
{ 1./sqrt(2), 0, -1./sqrt(2) },
{ 1./sqrt(6), -2./sqrt(6), 1./sqrt(6) },
};
uint8_t rgba_map[4];
ff_fill_rgba_map(rgba_map, inlink->format);
for (y = 0; y < 3; y++)
for (x = 0; x < 3; x++)
s->color_dct[y][x] = dct_3x3[rgba_map[y]][rgba_map[x]];
s->pr_width = inlink->w - (inlink->w - BSIZE) % s->step;
s->pr_height = inlink->h - (inlink->h - BSIZE) % s->step;
if (s->pr_width != inlink->w)
av_log(ctx, AV_LOG_WARNING, "The last %d horizontal pixels won't be denoised\n",
inlink->w - s->pr_width);
if (s->pr_height != inlink->h)
av_log(ctx, AV_LOG_WARNING, "The last %d vertical pixels won't be denoised\n",
inlink->h - s->pr_height);
s->p_linesize = linesize = FFALIGN(s->pr_width, 32);
for (i = 0; i < 2; i++) {
s->cbuf[i][0] = av_malloc(linesize * s->pr_height * sizeof(*s->cbuf[i][0]));
s->cbuf[i][1] = av_malloc(linesize * s->pr_height * sizeof(*s->cbuf[i][1]));
s->cbuf[i][2] = av_malloc(linesize * s->pr_height * sizeof(*s->cbuf[i][2]));
if (!s->cbuf[i][0] || !s->cbuf[i][1] || !s->cbuf[i][2])
return AVERROR(ENOMEM);
}
s->weights = av_malloc(s->pr_height * linesize * sizeof(*s->weights));
if (!s->weights)
return AVERROR(ENOMEM);
iweights = av_calloc(s->pr_height, linesize * sizeof(*iweights));
if (!iweights)
return AVERROR(ENOMEM);
for (y = 0; y < s->pr_height - BSIZE + 1; y += s->step)
for (x = 0; x < s->pr_width - BSIZE + 1; x += s->step)
for (by = 0; by < BSIZE; by++)
for (bx = 0; bx < BSIZE; bx++)
iweights[(y + by)*linesize + x + bx]++;
for (y = 0; y < s->pr_height; y++)
for (x = 0; x < s->pr_width; x++)
s->weights[y*linesize + x] = 1. / iweights[y*linesize + x];
av_free(iweights);
return 0;
}
static av_cold int init(AVFilterContext *ctx)
{
DCTdnoizContext *s = ctx->priv;
if (s->expr_str) {
int ret = av_expr_parse(&s->expr, s->expr_str, var_names,
NULL, NULL, NULL, NULL, 0, ctx);
if (ret < 0)
return ret;
}
s->th = s->sigma * 3.;
s->step = BSIZE - s->overlap;
s->dct = av_dct_init(NBITS, DCT_II);
s->idct = av_dct_init(NBITS, DCT_III);
s->block = av_malloc(BSIZE * BSIZE * sizeof(*s->block));
s->tmp_block = av_malloc(BSIZE * BSIZE * sizeof(*s->tmp_block));
if (!s->dct || !s->idct || !s->tmp_block || !s->block)
return AVERROR(ENOMEM);
return 0;
}
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_BGR24, AV_PIX_FMT_RGB24,
AV_PIX_FMT_NONE
};
ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
return 0;
}
static void color_decorrelation(float dct3ch[3][3], float **dst, int dst_linesize,
const uint8_t *src, int src_linesize, int w, int h)
{
int x, y;
float *dstp_r = dst[0];
float *dstp_g = dst[1];
float *dstp_b = dst[2];
for (y = 0; y < h; y++) {
const uint8_t *srcp = src;
for (x = 0; x < w; x++) {
dstp_r[x] = srcp[0] * dct3ch[0][0] + srcp[1] * dct3ch[0][1] + srcp[2] * dct3ch[0][2];
dstp_g[x] = srcp[0] * dct3ch[1][0] + srcp[1] * dct3ch[1][1] + srcp[2] * dct3ch[1][2];
dstp_b[x] = srcp[0] * dct3ch[2][0] + srcp[1] * dct3ch[2][1] + srcp[2] * dct3ch[2][2];
srcp += 3;
}
src += src_linesize;
dstp_r += dst_linesize;
dstp_g += dst_linesize;
dstp_b += dst_linesize;
}
}
static void color_correlation(float dct3ch[3][3], uint8_t *dst, int dst_linesize,
float **src, int src_linesize, int w, int h)
{
int x, y;
const float *src_r = src[0];
const float *src_g = src[1];
const float *src_b = src[2];
for (y = 0; y < h; y++) {
uint8_t *dstp = dst;
for (x = 0; x < w; x++) {
dstp[0] = av_clip_uint8(src_r[x] * dct3ch[0][0] + src_g[x] * dct3ch[1][0] + src_b[x] * dct3ch[2][0]);
dstp[1] = av_clip_uint8(src_r[x] * dct3ch[0][1] + src_g[x] * dct3ch[1][1] + src_b[x] * dct3ch[2][1]);
dstp[2] = av_clip_uint8(src_r[x] * dct3ch[0][2] + src_g[x] * dct3ch[1][2] + src_b[x] * dct3ch[2][2]);
dstp += 3;
}
dst += dst_linesize;
src_r += src_linesize;
src_g += src_linesize;
src_b += src_linesize;
}
}
static void filter_plane(AVFilterContext *ctx,
float *dst, int dst_linesize,
const float *src, int src_linesize,
int w, int h)
{
int x, y, bx, by;
DCTdnoizContext *s = ctx->priv;
float *dst0 = dst;
const float *weights = s->weights;
// reset block sums
memset(dst, 0, h * dst_linesize * sizeof(*dst));
// block dct sums
for (y = 0; y < h - BSIZE + 1; y += s->step) {
for (x = 0; x < w - BSIZE + 1; x += s->step) {
float *ftb = dct_block(s, src + x, src_linesize);
if (s->expr) {
for (by = 0; by < BSIZE; by++) {
for (bx = 0; bx < BSIZE; bx++) {
s->var_values[VAR_C] = FFABS(*ftb);
*ftb++ *= av_expr_eval(s->expr, s->var_values, s);
}
}
} else {
for (by = 0; by < BSIZE; by++) {
for (bx = 0; bx < BSIZE; bx++) {
if (FFABS(*ftb) < s->th)
*ftb = 0;
ftb++;
}
}
}
idct_block(s, dst + x, dst_linesize);
}
src += s->step * src_linesize;
dst += s->step * dst_linesize;
}
// average blocks
dst = dst0;
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++)
dst[x] *= weights[x];
dst += dst_linesize;
weights += dst_linesize;
}
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
DCTdnoizContext *s = ctx->priv;
AVFilterLink *outlink = inlink->dst->outputs[0];
int direct, plane;
AVFrame *out;
if (av_frame_is_writable(in)) {
direct = 1;
out = in;
} else {
direct = 0;
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);
}
color_decorrelation(s->color_dct, s->cbuf[0], s->p_linesize,
in->data[0], in->linesize[0], s->pr_width, s->pr_height);
for (plane = 0; plane < 3; plane++)
filter_plane(ctx, s->cbuf[1][plane], s->p_linesize,
s->cbuf[0][plane], s->p_linesize,
s->pr_width, s->pr_height);
color_correlation(s->color_dct, out->data[0], out->linesize[0],
s->cbuf[1], s->p_linesize, s->pr_width, s->pr_height);
if (!direct) {
int y;
uint8_t *dst = out->data[0];
const uint8_t *src = in->data[0];
const int dst_linesize = out->linesize[0];
const int src_linesize = in->linesize[0];
const int hpad = (inlink->w - s->pr_width) * 3;
const int vpad = (inlink->h - s->pr_height);
if (hpad) {
uint8_t *dstp = dst + s->pr_width * 3;
const uint8_t *srcp = src + s->pr_width * 3;
for (y = 0; y < s->pr_height; y++) {
memcpy(dstp, srcp, hpad);
dstp += dst_linesize;
srcp += src_linesize;
}
}
if (vpad) {
uint8_t *dstp = dst + s->pr_height * dst_linesize;
const uint8_t *srcp = src + s->pr_height * src_linesize;
for (y = 0; y < vpad; y++) {
memcpy(dstp, srcp, inlink->w * 3);
dstp += dst_linesize;
srcp += src_linesize;
}
}
av_frame_free(&in);
}
return ff_filter_frame(outlink, out);
}
static av_cold void uninit(AVFilterContext *ctx)
{
int i;
DCTdnoizContext *s = ctx->priv;
av_dct_end(s->dct);
av_dct_end(s->idct);
av_free(s->block);
av_free(s->tmp_block);
av_free(s->weights);
for (i = 0; i < 2; i++) {
av_free(s->cbuf[i][0]);
av_free(s->cbuf[i][1]);
av_free(s->cbuf[i][2]);
}
av_expr_free(s->expr);
}
static const AVFilterPad dctdnoiz_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.config_props = config_input,
},
{ NULL }
};
static const AVFilterPad dctdnoiz_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
AVFilter avfilter_vf_dctdnoiz = {
.name = "dctdnoiz",
.description = NULL_IF_CONFIG_SMALL("Denoise frames using 2D DCT."),
.priv_size = sizeof(DCTdnoizContext),
.init = init,
.uninit = uninit,
.query_formats = query_formats,
.inputs = dctdnoiz_inputs,
.outputs = dctdnoiz_outputs,
.priv_class = &dctdnoiz_class,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
};