ref: 0164a1cc5b13909407587109effabea92e487986
dir: /vp8/encoder/denoising.c/
/*
* Copyright (c) 2012 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "denoising.h"
#include "vp8/common/reconinter.h"
#include "vpx/vpx_integer.h"
#include "vpx_mem/vpx_mem.h"
#include "vpx_rtcd.h"
static const unsigned int NOISE_MOTION_THRESHOLD = 25 * 25;
/* SSE_DIFF_THRESHOLD is selected as ~95% confidence assuming
* var(noise) ~= 100.
*/
static const unsigned int SSE_DIFF_THRESHOLD = 16 * 16 * 20;
static const unsigned int SSE_THRESHOLD = 16 * 16 * 40;
/*
* The filtering coefficients used for denoizing are adjusted for static
* blocks, or blocks with very small motion vectors. This is done through
* the motion magnitude parameter.
*
* There are currently 2048 possible mapping from absolute difference to
* filter coefficient depending on the motion magnitude. Each mapping is
* in a LUT table. All these tables are staticly allocated but they are only
* filled on their first use.
*
* Each entry is a pair of 16b values, the coefficient and its complement
* to 256. Each of these value should only be 8b but they are 16b wide to
* avoid slow partial register manipulations.
*/
enum {num_motion_magnitude_adjustments = 2048};
static union coeff_pair filter_coeff_LUT[num_motion_magnitude_adjustments][256];
static uint8_t filter_coeff_LUT_initialized[num_motion_magnitude_adjustments] =
{ 0 };
union coeff_pair *vp8_get_filter_coeff_LUT(unsigned int motion_magnitude)
{
union coeff_pair *LUT;
unsigned int motion_magnitude_adjustment = motion_magnitude >> 3;
if (motion_magnitude_adjustment >= num_motion_magnitude_adjustments)
{
motion_magnitude_adjustment = num_motion_magnitude_adjustments - 1;
}
LUT = filter_coeff_LUT[motion_magnitude_adjustment];
if (!filter_coeff_LUT_initialized[motion_magnitude_adjustment])
{
int absdiff;
for (absdiff = 0; absdiff < 256; ++absdiff)
{
unsigned int filter_coefficient;
filter_coefficient = (255 << 8) / (256 + ((absdiff * 330) >> 3));
filter_coefficient += filter_coefficient /
(3 + motion_magnitude_adjustment);
if (filter_coefficient > 255)
{
filter_coefficient = 255;
}
LUT[absdiff].as_short[0] = filter_coefficient ;
LUT[absdiff].as_short[1] = 256 - filter_coefficient;
}
filter_coeff_LUT_initialized[motion_magnitude_adjustment] = 1;
}
return LUT;
}
int vp8_denoiser_filter_c(YV12_BUFFER_CONFIG *mc_running_avg,
YV12_BUFFER_CONFIG *running_avg,
MACROBLOCK *signal,
unsigned int motion_magnitude,
int y_offset,
int uv_offset)
{
unsigned char filtered_buf[16*16];
unsigned char *filtered = filtered_buf;
unsigned char *sig = signal->thismb;
int sig_stride = 16;
unsigned char *mc_running_avg_y = mc_running_avg->y_buffer + y_offset;
int mc_avg_y_stride = mc_running_avg->y_stride;
unsigned char *running_avg_y = running_avg->y_buffer + y_offset;
int avg_y_stride = running_avg->y_stride;
const union coeff_pair *LUT = vp8_get_filter_coeff_LUT(motion_magnitude);
int r, c;
int sum_diff = 0;
for (r = 0; r < 16; ++r)
{
/* Calculate absolute differences */
unsigned char abs_diff[16];
union coeff_pair filter_coefficient[16];
for (c = 0; c < 16; ++c)
{
int absdiff = sig[c] - mc_running_avg_y[c];
absdiff = absdiff > 0 ? absdiff : -absdiff;
abs_diff[c] = absdiff;
}
/* Use LUT to get filter coefficients (two 16b value; f and 256-f) */
for (c = 0; c < 16; ++c)
{
filter_coefficient[c] = LUT[abs_diff[c]];
}
/* Filtering... */
for (c = 0; c < 16; ++c)
{
const uint16_t state = (uint16_t)(mc_running_avg_y[c]);
const uint16_t sample = (uint16_t)(sig[c]);
running_avg_y[c] = (filter_coefficient[c].as_short[0] * state +
filter_coefficient[c].as_short[1] * sample + 128) >> 8;
}
/* Depending on the magnitude of the difference between the signal and
* filtered version, either replace the signal by the filtered one or
* update the filter state with the signal when the change in a pixel
* isn't classified as noise.
*/
for (c = 0; c < 16; ++c)
{
const int diff = sig[c] - running_avg_y[c];
sum_diff += diff;
if (diff * diff < NOISE_DIFF2_THRESHOLD)
{
filtered[c] = running_avg_y[c];
}
else
{
filtered[c] = sig[c];
running_avg_y[c] = sig[c];
}
}
/* Update pointers for next iteration. */
sig += sig_stride;
filtered += 16;
mc_running_avg_y += mc_avg_y_stride;
running_avg_y += avg_y_stride;
}
if (abs(sum_diff) > SUM_DIFF_THRESHOLD)
{
return COPY_BLOCK;
}
vp8_copy_mem16x16(filtered_buf, 16, signal->thismb, sig_stride);
return FILTER_BLOCK;
}
int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height)
{
int i;
assert(denoiser);
/* don't need one for intra start at 1 */
for (i = 1; i < MAX_REF_FRAMES; i++)
{
denoiser->yv12_running_avg[i].flags = 0;
if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_running_avg[i]), width,
height, VP8BORDERINPIXELS)
< 0)
{
vp8_denoiser_free(denoiser);
return 1;
}
vpx_memset(denoiser->yv12_running_avg[i].buffer_alloc, 0,
denoiser->yv12_running_avg[i].frame_size);
}
denoiser->yv12_mc_running_avg.flags = 0;
if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_mc_running_avg), width,
height, VP8BORDERINPIXELS) < 0)
{
vp8_denoiser_free(denoiser);
return 1;
}
vpx_memset(denoiser->yv12_mc_running_avg.buffer_alloc, 0,
denoiser->yv12_mc_running_avg.frame_size);
return 0;
}
void vp8_denoiser_free(VP8_DENOISER *denoiser)
{
int i;
assert(denoiser);
/* we don't have one for intra ref frame */
for (i = 1; i < MAX_REF_FRAMES ; i++)
{
vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_running_avg[i]);
}
vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_mc_running_avg);
}
void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
MACROBLOCK *x,
unsigned int best_sse,
unsigned int zero_mv_sse,
int recon_yoffset,
int recon_uvoffset)
{
int mv_row;
int mv_col;
unsigned int motion_magnitude2;
MV_REFERENCE_FRAME frame = x->best_reference_frame;
MV_REFERENCE_FRAME zero_frame = x->best_zeromv_reference_frame;
enum vp8_denoiser_decision decision = FILTER_BLOCK;
if (zero_frame)
{
YV12_BUFFER_CONFIG *src = &denoiser->yv12_running_avg[frame];
YV12_BUFFER_CONFIG *dst = &denoiser->yv12_mc_running_avg;
YV12_BUFFER_CONFIG saved_pre,saved_dst;
MB_MODE_INFO saved_mbmi;
MACROBLOCKD *filter_xd = &x->e_mbd;
MB_MODE_INFO *mbmi = &filter_xd->mode_info_context->mbmi;
int mv_col;
int mv_row;
int sse_diff = zero_mv_sse - best_sse;
saved_mbmi = *mbmi;
/* Use the best MV for the compensation. */
mbmi->ref_frame = x->best_reference_frame;
mbmi->mode = x->best_sse_inter_mode;
mbmi->mv = x->best_sse_mv;
mbmi->need_to_clamp_mvs = x->need_to_clamp_best_mvs;
mv_col = x->best_sse_mv.as_mv.col;
mv_row = x->best_sse_mv.as_mv.row;
if (frame == INTRA_FRAME ||
(mv_row *mv_row + mv_col *mv_col <= NOISE_MOTION_THRESHOLD &&
sse_diff < SSE_DIFF_THRESHOLD))
{
/*
* Handle intra blocks as referring to last frame with zero motion
* and let the absolute pixel difference affect the filter factor.
* Also consider small amount of motion as being random walk due
* to noise, if it doesn't mean that we get a much bigger error.
* Note that any changes to the mode info only affects the
* denoising.
*/
mbmi->ref_frame =
x->best_zeromv_reference_frame;
src = &denoiser->yv12_running_avg[zero_frame];
mbmi->mode = ZEROMV;
mbmi->mv.as_int = 0;
x->best_sse_inter_mode = ZEROMV;
x->best_sse_mv.as_int = 0;
best_sse = zero_mv_sse;
}
saved_pre = filter_xd->pre;
saved_dst = filter_xd->dst;
/* Compensate the running average. */
filter_xd->pre.y_buffer = src->y_buffer + recon_yoffset;
filter_xd->pre.u_buffer = src->u_buffer + recon_uvoffset;
filter_xd->pre.v_buffer = src->v_buffer + recon_uvoffset;
/* Write the compensated running average to the destination buffer. */
filter_xd->dst.y_buffer = dst->y_buffer + recon_yoffset;
filter_xd->dst.u_buffer = dst->u_buffer + recon_uvoffset;
filter_xd->dst.v_buffer = dst->v_buffer + recon_uvoffset;
if (!x->skip)
{
vp8_build_inter_predictors_mb(filter_xd);
}
else
{
vp8_build_inter16x16_predictors_mb(filter_xd,
filter_xd->dst.y_buffer,
filter_xd->dst.u_buffer,
filter_xd->dst.v_buffer,
filter_xd->dst.y_stride,
filter_xd->dst.uv_stride);
}
filter_xd->pre = saved_pre;
filter_xd->dst = saved_dst;
*mbmi = saved_mbmi;
}
mv_row = x->best_sse_mv.as_mv.row;
mv_col = x->best_sse_mv.as_mv.col;
motion_magnitude2 = mv_row * mv_row + mv_col * mv_col;
if (best_sse > SSE_THRESHOLD || motion_magnitude2
> 8 * NOISE_MOTION_THRESHOLD)
{
decision = COPY_BLOCK;
}
if (decision == FILTER_BLOCK)
{
/* Filter. */
decision = vp8_denoiser_filter(&denoiser->yv12_mc_running_avg,
&denoiser->yv12_running_avg[LAST_FRAME],
x,
motion_magnitude2,
recon_yoffset, recon_uvoffset);
}
if (decision == COPY_BLOCK)
{
/* No filtering of this block; it differs too much from the predictor,
* or the motion vector magnitude is considered too big.
*/
vp8_copy_mem16x16(
x->thismb, 16,
denoiser->yv12_running_avg[LAST_FRAME].y_buffer + recon_yoffset,
denoiser->yv12_running_avg[LAST_FRAME].y_stride);
}
}