ref: c73907a09b5d26010b7b4da960748664ff6bbd2c
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"
#if CONFIG_VP9_TEMPORAL_DENOISING
// For SVC: only do noise estimation on top spatial layer.
static INLINE int noise_est_svc(const struct VP9_COMP *const cpi) {
return (!cpi->use_svc ||
(cpi->use_svc &&
cpi->svc.spatial_layer_id == cpi->svc.number_spatial_layers - 1));
}
#endif
void vp9_noise_estimate_init(NOISE_ESTIMATE *const ne, int width, int height) {
ne->enabled = 0;
ne->level = kLowLow;
ne->value = 0;
ne->count = 0;
ne->thresh = 90;
ne->last_w = 0;
ne->last_h = 0;
if (width * height >= 1920 * 1080) {
ne->thresh = 200;
} else if (width * height >= 1280 * 720) {
ne->thresh = 140;
} else if (width * height >= 640 * 360) {
ne->thresh = 115;
}
ne->num_frames_estimate = 15;
}
static int enable_noise_estimation(VP9_COMP *const cpi) {
#if CONFIG_VP9_HIGHBITDEPTH
if (cpi->common.use_highbitdepth) return 0;
#endif
// Enable noise estimation if denoising is on.
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 && noise_est_svc(cpi) &&
cpi->common.width >= 320 && cpi->common.height >= 180)
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->resize_pending == 0 && !cpi->use_svc &&
cpi->oxcf.content != VP9E_CONTENT_SCREEN &&
cpi->common.width * cpi->common.height >= 640 * 360)
return 1;
else
return 0;
}
#if CONFIG_VP9_TEMPORAL_DENOISING
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;
}
}
#endif // CONFIG_VP9_TEMPORAL_DENOISING
NOISE_LEVEL vp9_noise_estimate_extract_level(NOISE_ESTIMATE *const ne) {
int noise_level = kLowLow;
if (ne->value > (ne->thresh << 1)) {
noise_level = kHigh;
} else {
if (ne->value > ne->thresh)
noise_level = kMedium;
else if (ne->value > ((9 * ne->thresh) >> 4))
noise_level = kLow;
else
noise_level = kLowLow;
}
return noise_level;
}
void vp9_update_noise_estimate(VP9_COMP *const cpi) {
const VP9_COMMON *const cm = &cpi->common;
NOISE_ESTIMATE *const ne = &cpi->noise_estimate;
const int low_res = (cm->width <= 352 && cm->height <= 288);
// Estimate of noise level every frame_period frames.
int frame_period = 8;
int thresh_consec_zeromv = 6;
unsigned int thresh_sum_diff = 100;
unsigned int thresh_sum_spatial = (200 * 200) << 8;
unsigned int thresh_spatial_var = (32 * 32) << 8;
int min_blocks_estimate = cm->mi_rows * cm->mi_cols >> 7;
int frame_counter = cm->current_video_frame;
// 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 && noise_est_svc(cpi)) {
last_source = &cpi->denoiser.last_source;
// Tune these thresholds for different resolutions when denoising is
// enabled.
if (cm->width > 640 && cm->width < 1920) {
thresh_consec_zeromv = 4;
thresh_sum_diff = 200;
thresh_sum_spatial = (120 * 120) << 8;
thresh_spatial_var = (48 * 48) << 8;
}
}
#endif
ne->enabled = enable_noise_estimation(cpi);
if (cpi->svc.number_spatial_layers > 1)
frame_counter = cpi->svc.current_superframe;
if (!ne->enabled || frame_counter % frame_period != 0 ||
last_source == NULL ||
(cpi->svc.number_spatial_layers == 1 &&
(ne->last_w != cm->width || ne->last_h != cm->height))) {
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 && noise_est_svc(cpi))
copy_frame(&cpi->denoiser.last_source, cpi->Source);
#endif
if (last_source != NULL) {
ne->last_w = cm->width;
ne->last_h = cm->height;
}
return;
} else if (cm->current_video_frame > 60 &&
cpi->rc.avg_frame_low_motion < (low_res ? 70 : 50)) {
// Force noise estimation to 0 and denoiser off if content has high motion.
ne->level = kLowLow;
ne->count = 0;
ne->num_frames_estimate = 10;
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 && noise_est_svc(cpi) &&
cpi->svc.current_superframe > 1) {
vp9_denoiser_set_noise_level(&cpi->denoiser, ne->level);
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] = { 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0 };
// 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;
int mi_row, mi_col;
int num_low_motion = 0;
int frame_low_motion = 1;
for (mi_row = 0; mi_row < cm->mi_rows; mi_row++) {
for (mi_col = 0; mi_col < cm->mi_cols; mi_col++) {
int bl_index = mi_row * cm->mi_cols + mi_col;
if (cpi->consec_zero_mv[bl_index] > thresh_consec_zeromv)
num_low_motion++;
}
}
if (num_low_motion < ((3 * cm->mi_rows * cm->mi_cols) >> 3))
frame_low_motion = 0;
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 && mi_row < cm->mi_rows - 1 &&
mi_col < cm->mi_cols - 1) {
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;
int consec_zeromv =
VPXMIN(cpi->consec_zero_mv[bl_index],
VPXMIN(cpi->consec_zero_mv[bl_index1],
VPXMIN(cpi->consec_zero_mv[bl_index2],
cpi->consec_zero_mv[bl_index3])));
// 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.
if (frame_low_motion && consec_zeromv > thresh_consec_zeromv) {
int is_skin = 0;
if (cpi->use_skin_detection) {
is_skin =
vp9_compute_skin_block(src_y, src_u, src_v, src_ystride,
src_uvstride, bsize, consec_zeromv, 0);
}
if (!is_skin) {
unsigned int sse;
// Compute variance.
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);
// Avoid blocks with high brightness and high spatial variance.
if ((sse2 - spatial_variance) < thresh_sum_spatial &&
spatial_variance < thresh_spatial_var) {
avg_est += low_res ? variance >> 4
: variance / ((spatial_variance >> 9) + 1);
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);
}
ne->last_w = cm->width;
ne->last_h = cm->height;
// 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 / num_samples;
// Update noise estimate.
ne->value = (int)((3 * ne->value + avg_est) >> 2);
ne->count++;
if (ne->count == ne->num_frames_estimate) {
// Reset counter and check noise level condition.
ne->num_frames_estimate = 30;
ne->count = 0;
ne->level = vp9_noise_estimate_extract_level(ne);
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 && noise_est_svc(cpi))
vp9_denoiser_set_noise_level(&cpi->denoiser, ne->level);
#endif
}
}
}
#if CONFIG_VP9_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 && noise_est_svc(cpi))
copy_frame(&cpi->denoiser.last_source, cpi->Source);
#endif
}