ref: 246e0eaa71b01e7d619f85e7c39bd3e837dab90e
dir: /vp9/encoder/vp9_noise_estimate.c/
/*
* Copyright (c) 2015 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 <assert.h>
#include <limits.h>
#include <math.h>
#include "./vpx_dsp_rtcd.h"
#include "vpx_dsp/vpx_dsp_common.h"
#include "vpx_scale/yv12config.h"
#include "vpx/vpx_integer.h"
#include "vp9/common/vp9_reconinter.h"
#include "vp9/encoder/vp9_context_tree.h"
#include "vp9/encoder/vp9_noise_estimate.h"
#include "vp9/encoder/vp9_encoder.h"
void vp9_noise_estimate_init(NOISE_ESTIMATE *const ne,
int width,
int height) {
ne->enabled = 0;
ne->level = kLow;
ne->value = 0;
ne->count = 0;
ne->thresh = 20;
if (width * height >= 1920 * 1080) {
ne->thresh = 70;
} else if (width * height >= 1280 * 720) {
ne->thresh = 40;
}
}
int enable_noise_estimation(VP9_COMP *const cpi) {
// Enable noise estimation if denoising is on (and cyclic refresh, since
// noise estimate is currently using a struct defined in cyclic refresh).
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 &&
cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ)
return 1;
#endif
// Only allow noise estimate under certain encoding mode.
// Enabled for 1 pass CBR, speed >=5, and if resolution is same as original.
// Not enabled for SVC mode and screen_content_mode.
// Not enabled for low resolutions.
if (cpi->oxcf.pass == 0 &&
cpi->oxcf.rc_mode == VPX_CBR &&
cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ &&
cpi->oxcf.speed >= 5 &&
cpi->resize_state == ORIG &&
!cpi->use_svc &&
cpi->oxcf.content != VP9E_CONTENT_SCREEN &&
cpi->common.width > 352 &&
cpi->common.height > 288)
return 1;
else
return 0;
}
static void copy_frame(YV12_BUFFER_CONFIG * const dest,
const YV12_BUFFER_CONFIG * const src) {
int r;
const uint8_t *srcbuf = src->y_buffer;
uint8_t *destbuf = dest->y_buffer;
assert(dest->y_width == src->y_width);
assert(dest->y_height == src->y_height);
for (r = 0; r < dest->y_height; ++r) {
memcpy(destbuf, srcbuf, dest->y_width);
destbuf += dest->y_stride;
srcbuf += src->y_stride;
}
}
void vp9_update_noise_estimate(VP9_COMP *const cpi) {
const VP9_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
NOISE_ESTIMATE *const ne = &cpi->noise_estimate;
// Estimate of noise level every frame_period frames.
int frame_period = 10;
int thresh_consec_zeromv = 8;
unsigned int thresh_sum_diff = 128;
int num_frames_estimate = 20;
int min_blocks_estimate = cm->mi_rows * cm->mi_cols >> 7;
// Estimate is between current source and last source.
YV12_BUFFER_CONFIG *last_source = cpi->Last_Source;
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0)
last_source = &cpi->denoiser.last_source;
#endif
ne->enabled = enable_noise_estimation(cpi);
if (!ne->enabled ||
cm->current_video_frame % frame_period != 0 ||
last_source == NULL) {
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0)
copy_frame(&cpi->denoiser.last_source, cpi->Source);
#endif
return;
} else {
int num_samples = 0;
uint64_t avg_est = 0;
int bsize = BLOCK_16X16;
static const unsigned char const_source[16] = {
128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
128, 128};
// Loop over sub-sample of 16x16 blocks of frame, and for blocks that have
// been encoded as zero/small mv at least x consecutive frames, compute
// the variance to update estimate of noise in the source.
const uint8_t *src_y = cpi->Source->y_buffer;
const int src_ystride = cpi->Source->y_stride;
const uint8_t *last_src_y = last_source->y_buffer;
const int last_src_ystride = last_source->y_stride;
const uint8_t *src_u = cpi->Source->u_buffer;
const uint8_t *src_v = cpi->Source->v_buffer;
const int src_uvstride = cpi->Source->uv_stride;
const int y_width_shift = (4 << b_width_log2_lookup[bsize]) >> 1;
const int y_height_shift = (4 << b_height_log2_lookup[bsize]) >> 1;
const int uv_width_shift = y_width_shift >> 1;
const int uv_height_shift = y_height_shift >> 1;
int mi_row, mi_col;
for (mi_row = 0; mi_row < cm->mi_rows; mi_row++) {
for (mi_col = 0; mi_col < cm->mi_cols; mi_col++) {
// 16x16 blocks, 1/4 sample of frame.
if (mi_row % 4 == 0 && mi_col % 4 == 0) {
int bl_index = mi_row * cm->mi_cols + mi_col;
int bl_index1 = bl_index + 1;
int bl_index2 = bl_index + cm->mi_cols;
int bl_index3 = bl_index2 + 1;
// Only consider blocks that are likely steady background. i.e, have
// been encoded as zero/low motion x (= thresh_consec_zeromv) frames
// in a row. consec_zero_mv[] defined for 8x8 blocks, so consider all
// 4 sub-blocks for 16x16 block. Also, avoid skin blocks.
const uint8_t ysource =
src_y[y_height_shift * src_ystride + y_width_shift];
const uint8_t usource =
src_u[uv_height_shift * src_uvstride + uv_width_shift];
const uint8_t vsource =
src_v[uv_height_shift * src_uvstride + uv_width_shift];
int is_skin = vp9_skin_pixel(ysource, usource, vsource);
if (cr->consec_zero_mv[bl_index] > thresh_consec_zeromv &&
cr->consec_zero_mv[bl_index1] > thresh_consec_zeromv &&
cr->consec_zero_mv[bl_index2] > thresh_consec_zeromv &&
cr->consec_zero_mv[bl_index3] > thresh_consec_zeromv &&
!is_skin) {
// Compute variance.
unsigned int sse;
unsigned int variance = cpi->fn_ptr[bsize].vf(src_y,
src_ystride,
last_src_y,
last_src_ystride,
&sse);
// Only consider this block as valid for noise measurement if the
// average term (sse - variance = N * avg^{2}, N = 16X16) of the
// temporal residual is small (avoid effects from lighting change).
if ((sse - variance) < thresh_sum_diff) {
unsigned int sse2;
const unsigned int spatial_variance =
cpi->fn_ptr[bsize].vf(src_y, src_ystride, const_source,
0, &sse2);
avg_est += variance / (10 + spatial_variance);
num_samples++;
}
}
}
src_y += 8;
last_src_y += 8;
src_u += 4;
src_v += 4;
}
src_y += (src_ystride << 3) - (cm->mi_cols << 3);
last_src_y += (last_src_ystride << 3) - (cm->mi_cols << 3);
src_u += (src_uvstride << 2) - (cm->mi_cols << 2);
src_v += (src_uvstride << 2) - (cm->mi_cols << 2);
}
// Update noise estimate if we have at a minimum number of block samples,
// and avg_est > 0 (avg_est == 0 can happen if the application inputs
// duplicate frames).
if (num_samples > min_blocks_estimate && avg_est > 0) {
// Normalize.
avg_est = (avg_est << 8) / num_samples;
// Update noise estimate.
ne->value = (3 * ne->value + avg_est) >> 2;
ne->count++;
if (ne->count == num_frames_estimate) {
// Reset counter and check noise level condition.
ne->count = 0;
if (ne->value > (ne->thresh << 1))
ne->level = kHigh;
else
if (ne->value > ne->thresh)
ne->level = kMedium;
else
ne->level = kLow;
}
}
}
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0) {
copy_frame(&cpi->denoiser.last_source, cpi->Source);
vp9_denoiser_set_noise_level(&cpi->denoiser, ne->level);
}
#endif
}