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/*
* Copyright (c) 2020, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
#include <assert.h>
#include <limits.h>
#include <math.h>
#include "config/aom_dsp_rtcd.h"
#include "aom_dsp/aom_dsp_common.h"
#include "aom_scale/yv12config.h"
#include "aom/aom_integer.h"
#include "av1/encoder/context_tree.h"
#include "av1/encoder/av1_noise_estimate.h"
#include "av1/encoder/encoder.h"
#if CONFIG_AV1_TEMPORAL_DENOISING
#include "av1/encoder/av1_temporal_denoiser.h"
#endif
#if CONFIG_AV1_TEMPORAL_DENOISING
// For SVC: only do noise estimation on top spatial layer.
static inline int noise_est_svc(const struct AV1_COMP *const cpi) {
return (!cpi->ppi->use_svc ||
(cpi->ppi->use_svc &&
cpi->svc.spatial_layer_id == cpi->svc.number_spatial_layers - 1));
}
#endif
void av1_noise_estimate_init(NOISE_ESTIMATE *const ne, int width, int height) {
const int64_t area = (int64_t)width * height;
ne->enabled = 0;
ne->level = (area < 1280 * 720) ? kLowLow : kLow;
ne->value = 0;
ne->count = 0;
ne->thresh = 90;
ne->last_w = 0;
ne->last_h = 0;
if (area >= 1920 * 1080) {
ne->thresh = 200;
} else if (area >= 1280 * 720) {
ne->thresh = 140;
} else if (area >= 640 * 360) {
ne->thresh = 115;
}
ne->num_frames_estimate = 15;
ne->adapt_thresh = (3 * ne->thresh) >> 1;
}
static int enable_noise_estimation(AV1_COMP *const cpi) {
const int resize_pending = is_frame_resize_pending(cpi);
#if CONFIG_AV1_HIGHBITDEPTH
if (cpi->common.seq_params->use_highbitdepth) return 0;
#endif
// Enable noise estimation if denoising is on.
#if CONFIG_AV1_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 == AOM_RC_ONE_PASS && cpi->oxcf.rc_cfg.mode == AOM_CBR &&
cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ && cpi->oxcf.speed >= 5 &&
resize_pending == 0 && !cpi->ppi->use_svc &&
cpi->oxcf.tune_cfg.content != AOM_CONTENT_SCREEN &&
cpi->common.width * cpi->common.height >= 640 * 360)
return 1;
else
return 0;
}
#if CONFIG_AV1_TEMPORAL_DENOISING
static void copy_frame(YV12_BUFFER_CONFIG *const dest,
const YV12_BUFFER_CONFIG *const src) {
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 (int r = 0; r < dest->y_height; ++r) {
memcpy(destbuf, srcbuf, dest->y_width);
destbuf += dest->y_stride;
srcbuf += src->y_stride;
}
}
#endif // CONFIG_AV1_TEMPORAL_DENOISING
NOISE_LEVEL av1_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 > (ne->thresh >> 1))
noise_level = kLow;
else
noise_level = kLowLow;
}
return noise_level;
}
void av1_update_noise_estimate(AV1_COMP *const cpi) {
const AV1_COMMON *const cm = &cpi->common;
const CommonModeInfoParams *const mi_params = &cm->mi_params;
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 = 2;
int frame_counter = cm->current_frame.frame_number;
// Estimate is between current source and last source.
YV12_BUFFER_CONFIG *last_source = cpi->last_source;
#if CONFIG_AV1_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 = 2;
}
}
#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_AV1_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 (frame_counter > 60 && cpi->svc.num_encoded_top_layer > 1 &&
cpi->rc.frames_since_key > cpi->svc.number_spatial_layers &&
cpi->svc.spatial_layer_id == cpi->svc.number_spatial_layers - 1 &&
cpi->rc.avg_frame_low_motion < (low_res ? 60 : 40)) {
// 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_AV1_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 && noise_est_svc(cpi) &&
cpi->svc.current_superframe > 1) {
av1_denoiser_set_noise_level(cpi, ne->level);
copy_frame(&cpi->denoiser.last_source, cpi->source);
}
#endif
return;
} else {
unsigned int bin_size = 100;
unsigned int hist[MAX_VAR_HIST_BINS] = { 0 };
unsigned int hist_avg[MAX_VAR_HIST_BINS];
unsigned int max_bin = 0;
unsigned int max_bin_count = 0;
unsigned int bin_cnt;
BLOCK_SIZE bsize = BLOCK_16X16;
// 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;
int mi_row, mi_col;
int num_low_motion = 0;
int frame_low_motion = 1;
for (mi_row = 0; mi_row < mi_params->mi_rows; mi_row += 2) {
for (mi_col = 0; mi_col < mi_params->mi_cols; mi_col += 2) {
int bl_index =
(mi_row >> 1) * (mi_params->mi_cols >> 1) + (mi_col >> 1);
if (cpi->consec_zero_mv[bl_index] > thresh_consec_zeromv)
num_low_motion++;
}
}
if (num_low_motion <
(((3 * (mi_params->mi_rows * mi_params->mi_cols) >> 2)) >> 3))
frame_low_motion = 0;
for (mi_row = 0; mi_row < mi_params->mi_rows; mi_row++) {
for (mi_col = 0; mi_col < mi_params->mi_cols; mi_col++) {
// 16x16 blocks, 1/4 sample of frame.
if (mi_row % 8 == 0 && mi_col % 8 == 0 &&
mi_row < mi_params->mi_rows - 3 &&
mi_col < mi_params->mi_cols - 3) {
int bl_index =
(mi_row >> 1) * (mi_params->mi_cols >> 1) + (mi_col >> 1);
int bl_index1 = bl_index + 1;
int bl_index2 = bl_index + (mi_params->mi_cols >> 1);
int bl_index3 = bl_index2 + 1;
int consec_zeromv =
AOMMIN(cpi->consec_zero_mv[bl_index],
AOMMIN(cpi->consec_zero_mv[bl_index1],
AOMMIN(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. And exclude this frame if
// high_source_sad is true (i.e., scene/content change).
if (frame_low_motion && consec_zeromv > thresh_consec_zeromv &&
!cpi->rc.high_source_sad) {
unsigned int sse;
// Compute variance between co-located blocks from current and
// last input frames.
unsigned int variance = cpi->ppi->fn_ptr[bsize].vf(
src_y, src_ystride, last_src_y, last_src_ystride, &sse);
unsigned int hist_index = variance / bin_size;
if (hist_index < MAX_VAR_HIST_BINS)
hist[hist_index]++;
else if (hist_index < 3 * (MAX_VAR_HIST_BINS >> 1))
hist[MAX_VAR_HIST_BINS - 1]++; // Account for the tail
}
}
src_y += 4;
last_src_y += 4;
}
src_y += (src_ystride << 2) - (mi_params->mi_cols << 2);
last_src_y += (last_src_ystride << 2) - (mi_params->mi_cols << 2);
}
ne->last_w = cm->width;
ne->last_h = cm->height;
// Adjust histogram to account for effect that histogram flattens
// and shifts to zero as scene darkens.
if (hist[0] > 10 && (hist[MAX_VAR_HIST_BINS - 1] > hist[0] >> 2)) {
hist[0] = 0;
hist[1] >>= 2;
hist[2] >>= 2;
hist[3] >>= 2;
hist[4] >>= 1;
hist[5] >>= 1;
hist[6] = 3 * hist[6] >> 1;
hist[MAX_VAR_HIST_BINS - 1] >>= 1;
}
// Average hist[] and find largest bin
for (bin_cnt = 0; bin_cnt < MAX_VAR_HIST_BINS; bin_cnt++) {
if (bin_cnt == 0)
hist_avg[bin_cnt] = (hist[0] + hist[1] + hist[2]) / 3;
else if (bin_cnt == MAX_VAR_HIST_BINS - 1)
hist_avg[bin_cnt] = hist[MAX_VAR_HIST_BINS - 1] >> 2;
else if (bin_cnt == MAX_VAR_HIST_BINS - 2)
hist_avg[bin_cnt] = (hist[bin_cnt - 1] + 2 * hist[bin_cnt] +
(hist[bin_cnt + 1] >> 1) + 2) >>
2;
else
hist_avg[bin_cnt] =
(hist[bin_cnt - 1] + 2 * hist[bin_cnt] + hist[bin_cnt + 1] + 2) >>
2;
if (hist_avg[bin_cnt] > max_bin_count) {
max_bin_count = hist_avg[bin_cnt];
max_bin = bin_cnt;
}
}
// Scale by 40 to work with existing thresholds
ne->value = (int)((3 * ne->value + max_bin * 40) >> 2);
// Quickly increase VNR strength when the noise level increases suddenly.
if (ne->level < kMedium && ne->value > ne->adapt_thresh) {
ne->count = ne->num_frames_estimate;
} else {
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 = av1_noise_estimate_extract_level(ne);
#if CONFIG_AV1_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 && noise_est_svc(cpi))
av1_denoiser_set_noise_level(cpi, ne->level);
#endif
}
}
#if CONFIG_AV1_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity > 0 && noise_est_svc(cpi))
copy_frame(&cpi->denoiser.last_source, cpi->source);
#endif
}