ref: 9ed1b2f09e9142687d4762d0c0906ebd9bfd167b
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"
const unsigned int NOISE_MOTION_THRESHOLD = 20*20;
const unsigned int NOISE_DIFF2_THRESHOLD = 75;
// SSE_DIFF_THRESHOLD is selected as ~95% confidence assuming var(noise) ~= 100.
const unsigned int SSE_DIFF_THRESHOLD = 16*16*20;
const unsigned int SSE_THRESHOLD = 16*16*40;
static __inline uint8_t blend(uint8_t state, uint8_t sample, uint8_t factor_q8)
{
return (uint8_t)(
(((uint16_t)factor_q8 * ((uint16_t)state) + // Q8
(uint16_t)(256 - factor_q8) * ((uint16_t)sample)) + 128) // Q8
>> 8);
}
static unsigned int denoiser_motion_compensate(YV12_BUFFER_CONFIG* src,
YV12_BUFFER_CONFIG* dst,
MACROBLOCK* x,
unsigned int best_sse,
unsigned int zero_mv_sse,
int recon_yoffset,
int recon_uvoffset)
{
MACROBLOCKD filter_xd = x->e_mbd;
int mv_col;
int mv_row;
int sse_diff = zero_mv_sse - best_sse;
// 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;
// Use the best MV for the compensation.
filter_xd.mode_info_context->mbmi.ref_frame = LAST_FRAME;
filter_xd.mode_info_context->mbmi.mode = filter_xd.best_sse_inter_mode;
filter_xd.mode_info_context->mbmi.mv = filter_xd.best_sse_mv;
filter_xd.mode_info_context->mbmi.need_to_clamp_mvs =
filter_xd.need_to_clamp_best_mvs;
mv_col = filter_xd.best_sse_mv.as_mv.col;
mv_row = filter_xd.best_sse_mv.as_mv.row;
if (filter_xd.mode_info_context->mbmi.mode <= B_PRED ||
(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.
filter_xd.mode_info_context->mbmi.ref_frame = LAST_FRAME;
filter_xd.mode_info_context->mbmi.mode = ZEROMV;
filter_xd.mode_info_context->mbmi.mv.as_int = 0;
x->e_mbd.best_sse_inter_mode = ZEROMV;
x->e_mbd.best_sse_mv.as_int = 0;
best_sse = zero_mv_sse;
}
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);
}
return best_sse;
}
static void denoiser_filter(YV12_BUFFER_CONFIG* mc_running_avg,
YV12_BUFFER_CONFIG* running_avg,
MACROBLOCK* signal,
unsigned int motion_magnitude2,
int y_offset,
int uv_offset)
{
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;
int r, c;
for (r = 0; r < 16; r++)
{
for (c = 0; c < 16; c++)
{
int diff;
int absdiff = 0;
unsigned int filter_coefficient;
absdiff = sig[c] - mc_running_avg_y[c];
absdiff = absdiff > 0 ? absdiff : -absdiff;
assert(absdiff >= 0 && absdiff < 256);
filter_coefficient = (255 << 8) / (256 + ((absdiff * 330) >> 3));
// Allow some additional filtering of static blocks, or blocks with very
// small motion vectors.
filter_coefficient += filter_coefficient / (3 + (motion_magnitude2 >> 3));
filter_coefficient = filter_coefficient > 255 ? 255 : filter_coefficient;
running_avg_y[c] = blend(mc_running_avg_y[c], sig[c], filter_coefficient);
diff = sig[c] - running_avg_y[c];
if (diff * diff < NOISE_DIFF2_THRESHOLD)
{
// Replace with mean to suppress the noise.
sig[c] = running_avg_y[c];
}
else
{
// Replace the filter state with the signal since the change in this
// pixel isn't classified as noise.
running_avg_y[c] = sig[c];
}
}
sig += sig_stride;
mc_running_avg_y += mc_avg_y_stride;
running_avg_y += avg_y_stride;
}
}
int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height)
{
assert(denoiser);
denoiser->yv12_running_avg.flags = 0;
if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_running_avg), width,
height, VP8BORDERINPIXELS) < 0)
{
vp8_denoiser_free(denoiser);
return 1;
}
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_running_avg.buffer_alloc, 0,
denoiser->yv12_running_avg.frame_size);
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)
{
assert(denoiser);
vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_running_avg);
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;
// Motion compensate the running average.
best_sse = denoiser_motion_compensate(&denoiser->yv12_running_avg,
&denoiser->yv12_mc_running_avg,
x,
best_sse,
zero_mv_sse,
recon_yoffset,
recon_uvoffset);
mv_row = x->e_mbd.best_sse_mv.as_mv.row;
mv_col = x->e_mbd.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)
{
// No filtering of this block since 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.y_buffer + recon_yoffset,
denoiser->yv12_running_avg.y_stride);
return;
}
// Filter.
denoiser_filter(&denoiser->yv12_mc_running_avg,
&denoiser->yv12_running_avg,
x,
motion_magnitude2,
recon_yoffset,
recon_uvoffset);
}