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aomedia / aom / a128fe458e6b817fdb1009f215c41a23ac563468 / . / av1 / encoder / temporal_filter.c
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/*
* Copyright (c) 2016, 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 <math.h>
#include <limits.h>
#include "config/aom_config.h"
#include "av1/common/alloccommon.h"
#include "av1/common/av1_common_int.h"
#include "av1/common/odintrin.h"
#include "av1/common/quant_common.h"
#include "av1/common/reconinter.h"
#include "av1/encoder/av1_quantize.h"
#include "av1/encoder/encoder.h"
#include "av1/encoder/extend.h"
#include "av1/encoder/firstpass.h"
#include "av1/encoder/mcomp.h"
#include "av1/encoder/ratectrl.h"
#include "av1/encoder/reconinter_enc.h"
#include "av1/encoder/segmentation.h"
#include "av1/encoder/temporal_filter.h"
#include "aom_dsp/aom_dsp_common.h"
#include "aom_mem/aom_mem.h"
#include "aom_ports/aom_timer.h"
#include "aom_ports/mem.h"
#include "aom_ports/system_state.h"
#include "aom_scale/aom_scale.h"
/*!\cond */
// NOTE: All `tf` in this file means `temporal filtering`.
// Forward Declaration.
static void tf_determine_block_partition(const MV block_mv, const int block_mse,
MV *subblock_mvs, int *subblock_mses);
/*!\endcond */
/*!\brief Does motion search for blocks in temporal filtering. This is
* the first step for temporal filtering. More specifically, given a frame to
* be filtered and another frame as reference, this function searches the
* reference frame to find out the most similar block as that from the frame
* to be filtered. This found block will be further used for weighted
* averaging.
*
* NOTE: Besides doing motion search for the entire block, this function will
* also do motion search for each 1/4 sub-block to get more precise
* predictions. Then, this function will determines whether to use 4
* sub-blocks to replace the entire block. If we do need to split the
* entire block, 4 elements in `subblock_mvs` and `subblock_mses` refer to
* the searched motion vector and search error (MSE) w.r.t. each sub-block
* respectively. Otherwise, the 4 elements will be the same, all of which
* are assigned as the searched motion vector and search error (MSE) for
* the entire block.
*
* \ingroup src_frame_proc
* \param[in] cpi Top level encoder instance structure
* \param[in] frame_to_filter Pointer to the frame to be filtered
* \param[in] ref_frame Pointer to the reference frame
* \param[in] block_size Block size used for motion search
* \param[in] mb_row Row index of the block in the frame
* \param[in] mb_col Column index of the block in the frame
* \param[in] ref_mv Reference motion vector, which is commonly
* inherited from the motion search result of
* previous frame.
* \param[out] subblock_mvs Pointer to the motion vectors for 4 sub-blocks
* \param[out] subblock_mses Pointer to the search errors (MSE) for 4
* sub-blocks
*
* \return Nothing will be returned. Results are saved in subblock_mvs and
* subblock_mses
*/
static void tf_motion_search(AV1_COMP *cpi,
const YV12_BUFFER_CONFIG *frame_to_filter,
const YV12_BUFFER_CONFIG *ref_frame,
const BLOCK_SIZE block_size, const int mb_row,
const int mb_col, MV *ref_mv, MV *subblock_mvs,
int *subblock_mses) {
// Frame information
const int min_frame_size = AOMMIN(cpi->common.width, cpi->common.height);
// Block information (ONLY Y-plane is used for motion search).
const int mb_height = block_size_high[block_size];
const int mb_width = block_size_wide[block_size];
const int mb_pels = mb_height * mb_width;
const int y_stride = frame_to_filter->y_stride;
assert(y_stride == ref_frame->y_stride);
const int y_offset = mb_row * mb_height * y_stride + mb_col * mb_width;
// Save input state.
MACROBLOCK *const mb = &cpi->td.mb;
MACROBLOCKD *const mbd = &mb->e_mbd;
const struct buf_2d ori_src_buf = mb->plane[0].src;
const struct buf_2d ori_pre_buf = mbd->plane[0].pre[0];
// Parameters used for motion search.
FULLPEL_MOTION_SEARCH_PARAMS full_ms_params;
SUBPEL_MOTION_SEARCH_PARAMS ms_params;
const SEARCH_METHODS search_method = NSTEP;
const search_site_config *search_site_cfg =
cpi->mv_search_params.search_site_cfg[SS_CFG_LOOKAHEAD];
const int step_param = av1_init_search_range(
AOMMAX(frame_to_filter->y_crop_width, frame_to_filter->y_crop_height));
const SUBPEL_SEARCH_TYPE subpel_search_type = USE_8_TAPS;
const int force_integer_mv = cpi->common.features.cur_frame_force_integer_mv;
const MV_COST_TYPE mv_cost_type =
min_frame_size >= 720
? MV_COST_L1_HDRES
: (min_frame_size >= 480 ? MV_COST_L1_MIDRES : MV_COST_L1_LOWRES);
// Starting position for motion search.
FULLPEL_MV start_mv = get_fullmv_from_mv(ref_mv);
// Baseline position for motion search (used for rate distortion comparison).
const MV baseline_mv = kZeroMv;
// Setup.
mb->plane[0].src.buf = frame_to_filter->y_buffer + y_offset;
mb->plane[0].src.stride = y_stride;
mbd->plane[0].pre[0].buf = ref_frame->y_buffer + y_offset;
mbd->plane[0].pre[0].stride = y_stride;
// Unused intermediate results for motion search.
unsigned int sse, error;
int distortion;
int cost_list[5];
// Do motion search.
int_mv best_mv; // Searched motion vector.
int block_mse = INT_MAX;
MV block_mv = kZeroMv;
av1_make_default_fullpel_ms_params(&full_ms_params, cpi, mb, block_size,
&baseline_mv, search_site_cfg,
/*fine_search_interval=*/0);
av1_set_mv_search_method(&full_ms_params, search_site_cfg, search_method);
full_ms_params.run_mesh_search = 1;
full_ms_params.mv_cost_params.mv_cost_type = mv_cost_type;
av1_full_pixel_search(start_mv, &full_ms_params, step_param,
cond_cost_list(cpi, cost_list), &best_mv.as_fullmv,
NULL);
if (force_integer_mv == 1) { // Only do full search on the entire block.
const int mv_row = best_mv.as_mv.row;
const int mv_col = best_mv.as_mv.col;
best_mv.as_mv.row = GET_MV_SUBPEL(mv_row);
best_mv.as_mv.col = GET_MV_SUBPEL(mv_col);
const int mv_offset = mv_row * y_stride + mv_col;
error = cpi->fn_ptr[block_size].vf(
ref_frame->y_buffer + y_offset + mv_offset, y_stride,
frame_to_filter->y_buffer + y_offset, y_stride, &sse);
block_mse = DIVIDE_AND_ROUND(error, mb_pels);
block_mv = best_mv.as_mv;
} else { // Do fractional search on the entire block and all sub-blocks.
av1_make_default_subpel_ms_params(&ms_params, cpi, mb, block_size,
&baseline_mv, cost_list);
ms_params.forced_stop = EIGHTH_PEL;
ms_params.var_params.subpel_search_type = subpel_search_type;
// Since we are merely refining the result from full pixel search, we don't
// need regularization for subpel search
ms_params.mv_cost_params.mv_cost_type = MV_COST_NONE;
MV subpel_start_mv = get_mv_from_fullmv(&best_mv.as_fullmv);
error = cpi->mv_search_params.find_fractional_mv_step(
&mb->e_mbd, &cpi->common, &ms_params, subpel_start_mv, &best_mv.as_mv,
&distortion, &sse, NULL);
block_mse = DIVIDE_AND_ROUND(error, mb_pels);
block_mv = best_mv.as_mv;
*ref_mv = best_mv.as_mv;
// On 4 sub-blocks.
const BLOCK_SIZE subblock_size = ss_size_lookup[block_size][1][1];
const int subblock_height = block_size_high[subblock_size];
const int subblock_width = block_size_wide[subblock_size];
const int subblock_pels = subblock_height * subblock_width;
start_mv = get_fullmv_from_mv(ref_mv);
int subblock_idx = 0;
for (int i = 0; i < mb_height; i += subblock_height) {
for (int j = 0; j < mb_width; j += subblock_width) {
const int offset = i * y_stride + j;
mb->plane[0].src.buf = frame_to_filter->y_buffer + y_offset + offset;
mbd->plane[0].pre[0].buf = ref_frame->y_buffer + y_offset + offset;
av1_make_default_fullpel_ms_params(&full_ms_params, cpi, mb,
subblock_size, &baseline_mv,
search_site_cfg,
/*fine_search_interval=*/0);
av1_set_mv_search_method(&full_ms_params, search_site_cfg,
search_method);
full_ms_params.run_mesh_search = 1;
full_ms_params.mv_cost_params.mv_cost_type = mv_cost_type;
av1_full_pixel_search(start_mv, &full_ms_params, step_param,
cond_cost_list(cpi, cost_list),
&best_mv.as_fullmv, NULL);
av1_make_default_subpel_ms_params(&ms_params, cpi, mb, subblock_size,
&baseline_mv, cost_list);
ms_params.forced_stop = EIGHTH_PEL;
ms_params.var_params.subpel_search_type = subpel_search_type;
// Since we are merely refining the result from full pixel search, we
// don't need regularization for subpel search
ms_params.mv_cost_params.mv_cost_type = MV_COST_NONE;
subpel_start_mv = get_mv_from_fullmv(&best_mv.as_fullmv);
error = cpi->mv_search_params.find_fractional_mv_step(
&mb->e_mbd, &cpi->common, &ms_params, subpel_start_mv,
&best_mv.as_mv, &distortion, &sse, NULL);
subblock_mses[subblock_idx] = DIVIDE_AND_ROUND(error, subblock_pels);
subblock_mvs[subblock_idx] = best_mv.as_mv;
++subblock_idx;
}
}
}
// Restore input state.
mb->plane[0].src = ori_src_buf;
mbd->plane[0].pre[0] = ori_pre_buf;
// Make partition decision.
tf_determine_block_partition(block_mv, block_mse, subblock_mvs,
subblock_mses);
// Do not pass down the reference motion vector if error is too large.
const int thresh = (min_frame_size >= 720) ? 12 : 3;
if (block_mse > (thresh << (mbd->bd - 8))) {
*ref_mv = kZeroMv;
}
}
/*!\cond */
// Determines whether to split the entire block to 4 sub-blocks for filtering.
// In particular, this decision is made based on the comparison between the
// motion search error of the entire block and the errors of all sub-blocks.
// Inputs:
// block_mv: Motion vector for the entire block (ONLY as reference).
// block_mse: Motion search error (MSE) for the entire block (ONLY as
// reference).
// subblock_mvs: Pointer to the motion vectors for 4 sub-blocks (will be
// modified based on the partition decision).
// subblock_mses: Pointer to the search errors (MSE) for 4 sub-blocks (will
// be modified based on the partition decision).
// Returns:
// Nothing will be returned. Results are saved in `subblock_mvs` and
// `subblock_mses`.
static void tf_determine_block_partition(const MV block_mv, const int block_mse,
MV *subblock_mvs, int *subblock_mses) {
int min_subblock_mse = INT_MAX;
int max_subblock_mse = INT_MIN;
int sum_subblock_mse = 0;
for (int i = 0; i < 4; ++i) {
sum_subblock_mse += subblock_mses[i];
min_subblock_mse = AOMMIN(min_subblock_mse, subblock_mses[i]);
max_subblock_mse = AOMMAX(max_subblock_mse, subblock_mses[i]);
}
// TODO(any): The following magic numbers may be tuned to improve the
// performance OR find a way to get rid of these magic numbers.
if (((block_mse * 15 < sum_subblock_mse * 4) &&
max_subblock_mse - min_subblock_mse < 48) ||
((block_mse * 14 < sum_subblock_mse * 4) &&
max_subblock_mse - min_subblock_mse < 24)) { // No split.
for (int i = 0; i < 4; ++i) {
subblock_mvs[i] = block_mv;
subblock_mses[i] = block_mse;
}
}
}
// Helper function to determine whether a frame is encoded with high bit-depth.
static INLINE int is_frame_high_bitdepth(const YV12_BUFFER_CONFIG *frame) {
return (frame->flags & YV12_FLAG_HIGHBITDEPTH) ? 1 : 0;
}
/*!\endcond */
/*!\brief Builds predictor for blocks in temporal filtering. This is the
* second step for temporal filtering, which is to construct predictions from
* all reference frames INCLUDING the frame to be filtered itself. These
* predictors are built based on the motion search results (motion vector is
* set as 0 for the frame to be filtered), and will be futher used for
* weighted averaging.
*
* \ingroup src_frame_proc
* \param[in] ref_frame Pointer to the reference frame (or the frame
* to be filtered)
* \param[in] mbd Pointer to the block for filtering. Besides
* containing the subsampling information of all
* planes, this field also gives the searched
* motion vector for the entire block, i.e.,
* `mbd->mi[0]->mv[0]`. This vector should be 0
* if the `ref_frame` itself is the frame to be
* filtered.
* \param[in] block_size Size of the block
* \param[in] mb_row Row index of the block in the frame
* \param[in] mb_col Column index of the block in the frame
* \param[in] num_planes Number of planes in the frame
* \param[in] scale Scaling factor
* \param[in] subblock_mvs The motion vectors for each sub-block (row-major
* order)
* \param[out] pred Pointer to the predictor to be built
*
* \return Nothing returned, But the contents of `pred` will be modified
*/
static void tf_build_predictor(const YV12_BUFFER_CONFIG *ref_frame,
const MACROBLOCKD *mbd,
const BLOCK_SIZE block_size, const int mb_row,
const int mb_col, const int num_planes,
const struct scale_factors *scale,
const MV *subblock_mvs, uint8_t *pred) {
// Information of the entire block.
const int mb_height = block_size_high[block_size]; // Height.
const int mb_width = block_size_wide[block_size]; // Width.
const int mb_pels = mb_height * mb_width; // Number of pixels.
const int mb_y = mb_height * mb_row; // Y-coord (Top-left).
const int mb_x = mb_width * mb_col; // X-coord (Top-left).
const int bit_depth = mbd->bd; // Bit depth.
const int is_intrabc = 0; // Is intra-copied?
const int is_high_bitdepth = is_frame_high_bitdepth(ref_frame);
// Default interpolation filters.
const int_interpfilters interp_filters =
av1_broadcast_interp_filter(MULTITAP_SHARP);
// Handle Y-plane, U-plane and V-plane (if needed) in sequence.
int plane_offset = 0;
for (int plane = 0; plane < num_planes; ++plane) {
const int subsampling_y = mbd->plane[plane].subsampling_y;
const int subsampling_x = mbd->plane[plane].subsampling_x;
// Information of each sub-block in current plane.
const int plane_h = mb_height >> subsampling_y; // Plane height.
const int plane_w = mb_width >> subsampling_x; // Plane width.
const int plane_y = mb_y >> subsampling_y; // Y-coord (Top-left).
const int plane_x = mb_x >> subsampling_x; // X-coord (Top-left).
const int h = plane_h >> 1; // Sub-block height.
const int w = plane_w >> 1; // Sub-block width.
const int is_y_plane = (plane == 0); // Is Y-plane?
const struct buf_2d ref_buf = { NULL, ref_frame->buffers[plane],
ref_frame->widths[is_y_plane ? 0 : 1],
ref_frame->heights[is_y_plane ? 0 : 1],
ref_frame->strides[is_y_plane ? 0 : 1] };
// Handle each subblock.
int subblock_idx = 0;
for (int i = 0; i < plane_h; i += h) {
for (int j = 0; j < plane_w; j += w) {
// Choose proper motion vector.
const MV mv = subblock_mvs[subblock_idx++];
assert(mv.row >= INT16_MIN && mv.row <= INT16_MAX &&
mv.col >= INT16_MIN && mv.col <= INT16_MAX);
const int y = plane_y + i;
const int x = plane_x + j;
// Build predictior for each sub-block on current plane.
InterPredParams inter_pred_params;
av1_init_inter_params(&inter_pred_params, w, h, y, x, subsampling_x,
subsampling_y, bit_depth, is_high_bitdepth,
is_intrabc, scale, &ref_buf, interp_filters);
inter_pred_params.conv_params = get_conv_params(0, plane, bit_depth);
av1_enc_build_one_inter_predictor(&pred[plane_offset + i * plane_w + j],
plane_w, &mv, &inter_pred_params);
}
}
plane_offset += mb_pels;
}
}
/*!\cond */
// Computes temporal filter weights and accumulators for the frame to be
// filtered. More concretely, the filter weights for all pixels are the same.
// Inputs:
// mbd: Pointer to the block for filtering, which is ONLY used to get
// subsampling information of all planes as well as the bit-depth.
// block_size: Size of the block.
// num_planes: Number of planes in the frame.
// pred: Pointer to the well-built predictors.
// accum: Pointer to the pixel-wise accumulator for filtering.
// count: Pointer to the pixel-wise counter fot filtering.
// Returns:
// Nothing will be returned. But the content to which `accum` and `pred`
// point will be modified.
void tf_apply_temporal_filter_self(const MACROBLOCKD *mbd,
const BLOCK_SIZE block_size,
const int num_planes, const uint8_t *pred,
uint32_t *accum, uint16_t *count) {
// Block information.
const int mb_height = block_size_high[block_size];
const int mb_width = block_size_wide[block_size];
const int mb_pels = mb_height * mb_width;
const int is_high_bitdepth = is_cur_buf_hbd(mbd);
const uint16_t *pred16 = CONVERT_TO_SHORTPTR(pred);
int plane_offset = 0;
for (int plane = 0; plane < num_planes; ++plane) {
const int subsampling_y = mbd->plane[plane].subsampling_y;
const int subsampling_x = mbd->plane[plane].subsampling_x;
const int h = mb_height >> subsampling_y; // Plane height.
const int w = mb_width >> subsampling_x; // Plane width.
int pred_idx = 0;
for (int i = 0; i < h; ++i) {
for (int j = 0; j < w; ++j) {
const int idx = plane_offset + pred_idx; // Index with plane shift.
const int pred_value = is_high_bitdepth ? pred16[idx] : pred[idx];
accum[idx] += TF_WEIGHT_SCALE * pred_value;
count[idx] += TF_WEIGHT_SCALE;
++pred_idx;
}
}
plane_offset += mb_pels;
}
}
// Function to compute pixel-wise squared difference between two buffers.
// Inputs:
// ref: Pointer to reference buffer.
// ref_offset: Start position of reference buffer for computation.
// ref_stride: Stride for reference buffer.
// tgt: Pointer to target buffer.
// tgt_offset: Start position of target buffer for computation.
// tgt_stride: Stride for target buffer.
// height: Height of block for computation.
// width: Width of block for computation.
// is_high_bitdepth: Whether the two buffers point to high bit-depth frames.
// square_diff: Pointer to save the squared differces.
// Returns:
// Nothing will be returned. But the content to which `square_diff` points
// will be modified.
static INLINE void compute_square_diff(const uint8_t *ref, const int ref_offset,
const int ref_stride, const uint8_t *tgt,
const int tgt_offset,
const int tgt_stride, const int height,
const int width,
const int is_high_bitdepth,
uint32_t *square_diff) {
const uint16_t *ref16 = CONVERT_TO_SHORTPTR(ref);
const uint16_t *tgt16 = CONVERT_TO_SHORTPTR(tgt);
int ref_idx = 0;
int tgt_idx = 0;
int idx = 0;
for (int i = 0; i < height; ++i) {
for (int j = 0; j < width; ++j) {
const uint16_t ref_value = is_high_bitdepth ? ref16[ref_offset + ref_idx]
: ref[ref_offset + ref_idx];
const uint16_t tgt_value = is_high_bitdepth ? tgt16[tgt_offset + tgt_idx]
: tgt[tgt_offset + tgt_idx];
const uint32_t diff = (ref_value > tgt_value) ? (ref_value - tgt_value)
: (tgt_value - ref_value);
square_diff[idx] = diff * diff;
++ref_idx;
++tgt_idx;
++idx;
}
ref_idx += (ref_stride - width);
tgt_idx += (tgt_stride - width);
}
}
// Function to accumulate pixel-wise squared difference between two luma buffers
// to be consumed while filtering the chroma planes.
// Inputs:
// square_diff: Pointer to squared differences from luma plane.
// luma_sse_sum: Pointer to save the sum of luma squared differences.
// block_height: Height of block for computation.
// block_width: Width of block for computation.
// ss_x_shift: Chroma subsampling shift in 'X' direction
// ss_y_shift: Chroma subsampling shift in 'Y' direction
// Returns:
// Nothing will be returned. But the content to which `luma_sse_sum` points
// will be modified.
void compute_luma_sq_error_sum(uint32_t *square_diff, uint32_t *luma_sse_sum,
int block_height, int block_width,
int ss_x_shift, int ss_y_shift) {
for (int i = 0; i < block_height; ++i) {
for (int j = 0; j < block_width; ++j) {
for (int ii = 0; ii < (1 << ss_y_shift); ++ii) {
for (int jj = 0; jj < (1 << ss_x_shift); ++jj) {
const int yy = (i << ss_y_shift) + ii; // Y-coord on Y-plane.
const int xx = (j << ss_x_shift) + jj; // X-coord on Y-plane.
const int ww = block_width << ss_x_shift; // Width of Y-plane.
luma_sse_sum[i * block_width + j] += square_diff[yy * ww + xx];
}
}
}
}
}
/*!\endcond */
/*!\brief Applies temporal filtering. NOTE that there are various optimised
* versions of this function called where the appropriate instruction set is
* supported.
*
* \ingroup src_frame_proc
* \param[in] frame_to_filter Pointer to the frame to be filtered, which is
* used as reference to compute squared
* difference from the predictor.
* \param[in] mbd Pointer to the block for filtering, ONLY used
* to get subsampling information for the planes
* \param[in] block_size Size of the block
* \param[in] mb_row Row index of the block in the frame
* \param[in] mb_col Column index of the block in the frame
* \param[in] num_planes Number of planes in the frame
* \param[in] noise_levels Estimated noise levels for each plane
* in the frame (Y,U,V)
* \param[in] subblock_mvs Pointer to the motion vectors for 4 sub-blocks
* \param[in] subblock_mses Pointer to the search errors (MSE) for 4
* sub-blocks
* \param[in] q_factor Quantization factor. This is actually the `q`
* defined in libaom, converted from `qindex`
* \param[in] filter_strength Filtering strength. This value lies in range
* [0, 6] where 6 is the maximum strength.
* \param[out] pred Pointer to the well-built predictors
* \param[out] accum Pointer to the pixel-wise accumulator for
* filtering
* \param[out] count Pointer to the pixel-wise counter for
* filtering
*
* \return Nothing returned, But the contents of `accum`, `pred` and 'count'
* will be modified
*/
void av1_apply_temporal_filter_c(
const YV12_BUFFER_CONFIG *frame_to_filter, const MACROBLOCKD *mbd,
const BLOCK_SIZE block_size, const int mb_row, const int mb_col,
const int num_planes, const double *noise_levels, const MV *subblock_mvs,
const int *subblock_mses, const int q_factor, const int filter_strength,
const uint8_t *pred, uint32_t *accum, uint16_t *count) {
// Block information.
const int mb_height = block_size_high[block_size];
const int mb_width = block_size_wide[block_size];
const int mb_pels = mb_height * mb_width;
const int is_high_bitdepth = is_frame_high_bitdepth(frame_to_filter);
const uint16_t *pred16 = CONVERT_TO_SHORTPTR(pred);
// Frame information.
const int frame_height = frame_to_filter->y_crop_height;
const int frame_width = frame_to_filter->y_crop_width;
const int min_frame_size = AOMMIN(frame_height, frame_width);
// Variables to simplify combined error calculation.
const double inv_factor = 1.0 / ((TF_WINDOW_BLOCK_BALANCE_WEIGHT + 1) *
TF_SEARCH_ERROR_NORM_WEIGHT);
const double weight_factor =
(double)TF_WINDOW_BLOCK_BALANCE_WEIGHT * inv_factor;
// Decay factors for non-local mean approach.
double decay_factor[MAX_MB_PLANE] = { 0 };
// Smaller q -> smaller filtering weight.
double q_decay = pow((double)q_factor / TF_Q_DECAY_THRESHOLD, 2);
q_decay = CLIP(q_decay, 1e-5, 1);
// Smaller strength -> smaller filtering weight.
double s_decay = pow((double)filter_strength / TF_STRENGTH_THRESHOLD, 2);
s_decay = CLIP(s_decay, 1e-5, 1);
for (int plane = 0; plane < num_planes; plane++) {
// Larger noise -> larger filtering weight.
const double n_decay = 0.5 + log(2 * noise_levels[plane] + 5.0);
decay_factor[plane] = 1 / (n_decay * q_decay * s_decay);
}
double d_factor[4] = { 0 };
for (int subblock_idx = 0; subblock_idx < 4; subblock_idx++) {
// Larger motion vector -> smaller filtering weight.
const MV mv = subblock_mvs[subblock_idx];
const double distance = sqrt(pow(mv.row, 2) + pow(mv.col, 2));
double distance_threshold = min_frame_size * TF_SEARCH_DISTANCE_THRESHOLD;
distance_threshold = AOMMAX(distance_threshold, 1);
d_factor[subblock_idx] = distance / distance_threshold;
d_factor[subblock_idx] = AOMMAX(d_factor[subblock_idx], 1);
}
// Allocate memory for pixel-wise squared differences. They,
// regardless of the subsampling, are assigned with memory of size `mb_pels`.
uint32_t *square_diff = aom_memalign(16, mb_pels * sizeof(uint32_t));
memset(square_diff, 0, mb_pels * sizeof(square_diff[0]));
// Allocate memory for accumulated luma squared error. This value will be
// consumed while filtering the chroma planes.
uint32_t *luma_sse_sum = aom_memalign(32, mb_pels * sizeof(uint32_t));
memset(luma_sse_sum, 0, mb_pels * sizeof(luma_sse_sum[0]));
// Get window size for pixel-wise filtering.
assert(TF_WINDOW_LENGTH % 2 == 1);
const int half_window = TF_WINDOW_LENGTH >> 1;
// Handle planes in sequence.
int plane_offset = 0;
for (int plane = 0; plane < num_planes; ++plane) {
// Locate pixel on reference frame.
const int subsampling_y = mbd->plane[plane].subsampling_y;
const int subsampling_x = mbd->plane[plane].subsampling_x;
const int h = mb_height >> subsampling_y; // Plane height.
const int w = mb_width >> subsampling_x; // Plane width.
const int frame_stride =
frame_to_filter->strides[plane == AOM_PLANE_Y ? 0 : 1];
const int frame_offset = mb_row * h * frame_stride + mb_col * w;
const uint8_t *ref = frame_to_filter->buffers[plane];
const int ss_y_shift =
subsampling_y - mbd->plane[AOM_PLANE_Y].subsampling_y;
const int ss_x_shift =
subsampling_x - mbd->plane[AOM_PLANE_Y].subsampling_x;
const int num_ref_pixels = TF_WINDOW_LENGTH * TF_WINDOW_LENGTH +
((plane) ? (1 << (ss_x_shift + ss_y_shift)) : 0);
const double inv_num_ref_pixels = 1.0 / num_ref_pixels;
// Filter U-plane and V-plane using Y-plane. This is because motion
// search is only done on Y-plane, so the information from Y-plane will
// be more accurate. The luma sse sum is reused in both chroma planes.
if (plane == AOM_PLANE_U)
compute_luma_sq_error_sum(square_diff, luma_sse_sum, h, w, ss_x_shift,
ss_y_shift);
compute_square_diff(ref, frame_offset, frame_stride, pred, plane_offset, w,
h, w, is_high_bitdepth, square_diff);
// Perform filtering.
int pred_idx = 0;
for (int i = 0; i < h; ++i) {
for (int j = 0; j < w; ++j) {
// non-local mean approach
uint64_t sum_square_diff = 0;
for (int wi = -half_window; wi <= half_window; ++wi) {
for (int wj = -half_window; wj <= half_window; ++wj) {
const int y = CLIP(i + wi, 0, h - 1); // Y-coord on current plane.
const int x = CLIP(j + wj, 0, w - 1); // X-coord on current plane.
sum_square_diff += square_diff[y * w + x];
}
}
sum_square_diff += luma_sse_sum[i * w + j];
// Scale down the difference for high bit depth input.
if (mbd->bd > 8) sum_square_diff >>= ((mbd->bd - 8) * 2);
// Combine window error and block error, and normalize it.
const double window_error = sum_square_diff * inv_num_ref_pixels;
const int subblock_idx = (i >= h / 2) * 2 + (j >= w / 2);
const double block_error = (double)subblock_mses[subblock_idx];
const double combined_error =
weight_factor * window_error + block_error * inv_factor;
// Compute filter weight.
double scaled_error =
combined_error * d_factor[subblock_idx] * decay_factor[plane];
scaled_error = AOMMIN(scaled_error, 7);
const int weight = (int)(exp(-scaled_error) * TF_WEIGHT_SCALE);
const int idx = plane_offset + pred_idx; // Index with plane shift.
const int pred_value = is_high_bitdepth ? pred16[idx] : pred[idx];
accum[idx] += weight * pred_value;
count[idx] += weight;
++pred_idx;
}
}
plane_offset += mb_pels;
}
aom_free(square_diff);
aom_free(luma_sse_sum);
}
#if CONFIG_AV1_HIGHBITDEPTH
// Calls High bit-depth temporal filter
void av1_highbd_apply_temporal_filter_c(
const YV12_BUFFER_CONFIG *frame_to_filter, const MACROBLOCKD *mbd,
const BLOCK_SIZE block_size, const int mb_row, const int mb_col,
const int num_planes, const double *noise_levels, const MV *subblock_mvs,
const int *subblock_mses, const int q_factor, const int filter_strength,
const uint8_t *pred, uint32_t *accum, uint16_t *count) {
av1_apply_temporal_filter_c(frame_to_filter, mbd, block_size, mb_row, mb_col,
num_planes, noise_levels, subblock_mvs,
subblock_mses, q_factor, filter_strength, pred,
accum, count);
}
#endif // CONFIG_AV1_HIGHBITDEPTH
/*!\brief Normalizes the accumulated filtering result to produce the filtered
* frame
*
* \ingroup src_frame_proc
* \param[in] mbd Pointer to the block for filtering, which is
* ONLY used to get subsampling information for
* all the planes
* \param[in] block_size Size of the block
* \param[in] mb_row Row index of the block in the frame
* \param[in] mb_col Column index of the block in the frame
* \param[in] num_planes Number of planes in the frame
* \param[in] accum Pointer to the pre-computed accumulator
* \param[in] count Pointer to the pre-computed count
* \param[out] result_buffer Pointer to result buffer
*
* \return Nothing returned, but the content to which `result_buffer` pointer
* will be modified
*/
static void tf_normalize_filtered_frame(
const MACROBLOCKD *mbd, const BLOCK_SIZE block_size, const int mb_row,
const int mb_col, const int num_planes, const uint32_t *accum,
const uint16_t *count, YV12_BUFFER_CONFIG *result_buffer) {
// Block information.
const int mb_height = block_size_high[block_size];
const int mb_width = block_size_wide[block_size];
const int mb_pels = mb_height * mb_width;
const int is_high_bitdepth = is_frame_high_bitdepth(result_buffer);
int plane_offset = 0;
for (int plane = 0; plane < num_planes; ++plane) {
const int plane_h = mb_height >> mbd->plane[plane].subsampling_y;
const int plane_w = mb_width >> mbd->plane[plane].subsampling_x;
const int frame_stride = result_buffer->strides[plane == 0 ? 0 : 1];
const int frame_offset = mb_row * plane_h * frame_stride + mb_col * plane_w;
uint8_t *const buf = result_buffer->buffers[plane];
uint16_t *const buf16 = CONVERT_TO_SHORTPTR(buf);
int plane_idx = 0; // Pixel index on current plane (block-base).
int frame_idx = frame_offset; // Pixel index on the entire frame.
for (int i = 0; i < plane_h; ++i) {
for (int j = 0; j < plane_w; ++j) {
const int idx = plane_idx + plane_offset;
const uint16_t rounding = count[idx] >> 1;
if (is_high_bitdepth) {
buf16[frame_idx] =
(uint16_t)OD_DIVU(accum[idx] + rounding, count[idx]);
} else {
buf[frame_idx] = (uint8_t)OD_DIVU(accum[idx] + rounding, count[idx]);
}
++plane_idx;
++frame_idx;
}
frame_idx += (frame_stride - plane_w);
}
plane_offset += mb_pels;
}
}
/*!\cond */
// Helper function to compute number of blocks on either side of the frame.
static INLINE int get_num_blocks(const int frame_length, const int mb_length) {
return (frame_length + mb_length - 1) / mb_length;
}
// Helper function to get `q` used for encoding.
static INLINE int get_q(const AV1_COMP *cpi) {
const FRAME_TYPE frame_type =
(cpi->common.current_frame.frame_number > 1) ? INTER_FRAME : KEY_FRAME;
const int q = (int)av1_convert_qindex_to_q(
cpi->rc.avg_frame_qindex[frame_type], cpi->common.seq_params.bit_depth);
return q;
}
/*!\endcond */
/*!
* \brief Sum and SSE source vs filtered framee difference returned by
* temporal filter.
*/
typedef struct {
/*!\cond */
int64_t sum;
int64_t sse;
/*!\endcond */
} FRAME_DIFF;
/*!\brief Does temporal filter for a given frame.
*
* \ingroup src_frame_proc
* \param[in] cpi Top level encoder instance structure
* \param[in] frames Frame buffers used for temporal filtering
* \param[in] num_frames Number of frames in the frame buffer
* \param[in] filter_frame_idx Index of the frame to be filtered
* \param[in] check_show_existing whether to accumulate diff for show
existing condition check
* \param[in] block_size Block size used for temporal filtering
* \param[in] scale Frame scaling factor
* \param[in] noise_levels Estimated noise levels for each plane
* in the frame (Y,U,V)
*
* \return Difference between filtered frame and the original frame
* (sum and sse)
*/
static FRAME_DIFF tf_do_filtering(AV1_COMP *cpi, YV12_BUFFER_CONFIG **frames,
const int num_frames,
const int filter_frame_idx,
const int check_show_existing,
const BLOCK_SIZE block_size,
const struct scale_factors *scale,
const double *noise_levels) {
// Basic information.
const YV12_BUFFER_CONFIG *const frame_to_filter = frames[filter_frame_idx];
const int frame_height = frame_to_filter->y_crop_height;
const int frame_width = frame_to_filter->y_crop_width;
const int mb_height = block_size_high[block_size];
const int mb_width = block_size_wide[block_size];
const int mb_pels = mb_height * mb_width;
const int mb_rows = get_num_blocks(frame_height, mb_height);
const int mb_cols = get_num_blocks(frame_width, mb_width);
const int num_planes = av1_num_planes(&cpi->common);
const int mi_h = mi_size_high_log2[block_size];
const int mi_w = mi_size_wide_log2[block_size];
assert(num_planes >= 1 && num_planes <= MAX_MB_PLANE);
const int is_high_bitdepth = is_frame_high_bitdepth(frame_to_filter);
// Quantization factor used in temporal filtering.
const int q_factor = get_q(cpi);
// Factor to control the filering strength.
const int filter_strength = cpi->oxcf.algo_cfg.arnr_strength;
// Save input state.
MACROBLOCK *const mb = &cpi->td.mb;
MACROBLOCKD *const mbd = &mb->e_mbd;
uint8_t *input_buffer[MAX_MB_PLANE];
for (int i = 0; i < num_planes; i++) {
input_buffer[i] = mbd->plane[i].pre[0].buf;
}
MB_MODE_INFO **input_mb_mode_info = mbd->mi;
// Setup.
mbd->block_ref_scale_factors[0] = scale;
mbd->block_ref_scale_factors[1] = scale;
// A temporary block info used to store state in temporal filtering process.
MB_MODE_INFO *tmp_mb_mode_info = (MB_MODE_INFO *)malloc(sizeof(MB_MODE_INFO));
memset(tmp_mb_mode_info, 0, sizeof(MB_MODE_INFO));
mbd->mi = &tmp_mb_mode_info;
mbd->mi[0]->motion_mode = SIMPLE_TRANSLATION;
// Allocate memory for predictor, accumulator and count.
uint8_t *pred8 = aom_memalign(32, num_planes * mb_pels * sizeof(uint8_t));
uint16_t *pred16 = aom_memalign(32, num_planes * mb_pels * sizeof(uint16_t));
uint32_t *accum = aom_memalign(16, num_planes * mb_pels * sizeof(uint32_t));
uint16_t *count = aom_memalign(16, num_planes * mb_pels * sizeof(uint16_t));
memset(pred8, 0, num_planes * mb_pels * sizeof(pred8[0]));
memset(pred16, 0, num_planes * mb_pels * sizeof(pred16[0]));
uint8_t *const pred = is_high_bitdepth ? CONVERT_TO_BYTEPTR(pred16) : pred8;
// Do filtering.
FRAME_DIFF diff = { 0, 0 };
// Perform temporal filtering block by block.
for (int mb_row = 0; mb_row < mb_rows; mb_row++) {
av1_set_mv_row_limits(&cpi->common.mi_params, &mb->mv_limits,
(mb_row << mi_h), (mb_height >> MI_SIZE_LOG2),
cpi->oxcf.border_in_pixels);
for (int mb_col = 0; mb_col < mb_cols; mb_col++) {
av1_set_mv_col_limits(&cpi->common.mi_params, &mb->mv_limits,
(mb_col << mi_w), (mb_width >> MI_SIZE_LOG2),
cpi->oxcf.border_in_pixels);
memset(accum, 0, num_planes * mb_pels * sizeof(accum[0]));
memset(count, 0, num_planes * mb_pels * sizeof(count[0]));
MV ref_mv = kZeroMv; // Reference motion vector passed down along frames.
// Perform temporal filtering frame by frame.
for (int frame = 0; frame < num_frames; frame++) {
if (frames[frame] == NULL) continue;
// Motion search.
MV subblock_mvs[4] = { kZeroMv, kZeroMv, kZeroMv, kZeroMv };
int subblock_mses[4] = { INT_MAX, INT_MAX, INT_MAX, INT_MAX };
if (frame == filter_frame_idx) { // Frame to be filtered.
// Change ref_mv sign for following frames.
ref_mv.row *= -1;
ref_mv.col *= -1;
} else { // Other reference frames.
tf_motion_search(cpi, frame_to_filter, frames[frame], block_size,
mb_row, mb_col, &ref_mv, subblock_mvs,
subblock_mses);
}
tf_build_predictor(frames[frame], mbd, block_size, mb_row, mb_col,
num_planes, scale, subblock_mvs, pred);
// Perform weighted averaging.
if (frame == filter_frame_idx) { // Frame to be filtered.
tf_apply_temporal_filter_self(mbd, block_size, num_planes, pred,
accum, count);
} else { // Other reference frames.
// TODO(any): avx2/sse2 version should be changed to align with C
// function before using. In particular, current avx2/sse2 function
// only supports 32x32 block size and 5x5 filtering window.
if (is_frame_high_bitdepth(frame_to_filter)) { // for high bit-depth
#if CONFIG_AV1_HIGHBITDEPTH
if (TF_BLOCK_SIZE == BLOCK_32X32 && TF_WINDOW_LENGTH == 5) {
av1_highbd_apply_temporal_filter(
frame_to_filter, mbd, block_size, mb_row, mb_col, num_planes,
noise_levels, subblock_mvs, subblock_mses, q_factor,
filter_strength, pred, accum, count);
} else {
#endif // CONFIG_AV1_HIGHBITDEPTH
av1_apply_temporal_filter_c(
frame_to_filter, mbd, block_size, mb_row, mb_col, num_planes,
noise_levels, subblock_mvs, subblock_mses, q_factor,
filter_strength, pred, accum, count);
#if CONFIG_AV1_HIGHBITDEPTH
}
#endif // CONFIG_AV1_HIGHBITDEPTH
} else { // for 8-bit
if (TF_BLOCK_SIZE == BLOCK_32X32 && TF_WINDOW_LENGTH == 5) {
av1_apply_temporal_filter(
frame_to_filter, mbd, block_size, mb_row, mb_col, num_planes,
noise_levels, subblock_mvs, subblock_mses, q_factor,
filter_strength, pred, accum, count);
} else {
av1_apply_temporal_filter_c(
frame_to_filter, mbd, block_size, mb_row, mb_col, num_planes,
noise_levels, subblock_mvs, subblock_mses, q_factor,
filter_strength, pred, accum, count);
}
}
}
}
tf_normalize_filtered_frame(mbd, block_size, mb_row, mb_col, num_planes,
accum, count, &cpi->alt_ref_buffer);
if (check_show_existing) {
const int y_height = mb_height >> mbd->plane[0].subsampling_y;
const int y_width = mb_width >> mbd->plane[0].subsampling_x;
const int source_y_stride = frame_to_filter->y_stride;
const int filter_y_stride = cpi->alt_ref_buffer.y_stride;
const int source_offset =
mb_row * y_height * source_y_stride + mb_col * y_width;
const int filter_offset =
mb_row * y_height * filter_y_stride + mb_col * y_width;
unsigned int sse = 0;
cpi->fn_ptr[block_size].vf(frame_to_filter->y_buffer + source_offset,
source_y_stride,
cpi->alt_ref_buffer.y_buffer + filter_offset,
filter_y_stride, &sse);
diff.sum += sse;
diff.sse += sse * sse;
}
}
}
// Restore input state
for (int i = 0; i < num_planes; i++) {
mbd->plane[i].pre[0].buf = input_buffer[i];
}
mbd->mi = input_mb_mode_info;
free(tmp_mb_mode_info);
aom_free(pred8);
aom_free(pred16);
aom_free(accum);
aom_free(count);
return diff;
}
/*!\brief Setups the frame buffer for temporal filtering. This fuction
* determines how many frames will be used for temporal filtering and then
* groups them into a buffer. This function will also estimate the noise level
* of the to-filter frame.
*
* \ingroup src_frame_proc
* \param[in] cpi Top level encoder instance structure
* \param[in] filter_frame_lookahead_idx The index of the to-filter frame
* in the lookahead buffer cpi->lookahead
* \param[in] is_second_arf Whether the to-filter frame is the second ARF.
* This field will affect the number of frames
* used for filtering.
* \param[in,out] frames Pointer to the frame buffer to setup
* \param[in,out] num_frames_for_filtering Number of frames used for filtering
* \param[in,out] filter_frame_idx Index of the to-filter frame in the setup
* frame buffer.
* \param[out] noise_levels Pointer to the noise levels of the to-filter
* frame, estimated with each plane (in Y, U, V
* order).
*
* \return Nothing will be returned. But the frame buffer `frames`, number of
* frames in the buffer `num_frames_for_filtering`, and the index of
* the to-filter frame in the buffer `filter_frame_idx` will be updated
* in this function. Estimated noise levels for YUV planes will be
* saved in `noise_levels`.
*/
static void tf_setup_filtering_buffer(const AV1_COMP *cpi,
const int filter_frame_lookahead_idx,
const int is_second_arf,
YV12_BUFFER_CONFIG **frames,
int *num_frames_for_filtering,
int *filter_frame_idx,
double *noise_levels) {
// Number of frames used for filtering. Set `arnr_max_frames` as 1 to disable
// temporal filtering.
int num_frames = AOMMAX(cpi->oxcf.algo_cfg.arnr_max_frames, 1);
int num_before = 0; // Number of filtering frames before the to-filter frame.
int num_after = 0; // Number of filtering frames after the to-filer frame.
const int lookahead_depth =
av1_lookahead_depth(cpi->lookahead, cpi->compressor_stage);
// Temporal filtering should not go beyond key frames
const int key_to_curframe =
AOMMAX(cpi->rc.frames_since_key +
cpi->gf_group.arf_src_offset[cpi->gf_group.index],
0);
const int curframe_to_key =
AOMMAX(cpi->rc.frames_to_key -
cpi->gf_group.arf_src_offset[cpi->gf_group.index] - 1,
0);
// Number of buffered frames before the to-filter frame.
const int max_before =
AOMMIN(filter_frame_lookahead_idx < -1 ? -filter_frame_lookahead_idx + 1
: filter_frame_lookahead_idx + 1,
key_to_curframe);
// Number of buffered frames after the to-filter frame.
const int max_after = AOMMIN(lookahead_depth - max_before, curframe_to_key);
const int filter_frame_offset = filter_frame_lookahead_idx < -1
? -filter_frame_lookahead_idx
: filter_frame_lookahead_idx;
// Estimate noises for each plane.
const struct lookahead_entry *to_filter_buf = av1_lookahead_peek(
cpi->lookahead, filter_frame_offset, cpi->compressor_stage);
assert(to_filter_buf != NULL);
const YV12_BUFFER_CONFIG *to_filter_frame = &to_filter_buf->img;
const int num_planes = av1_num_planes(&cpi->common);
for (int plane = 0; plane < num_planes; ++plane) {
noise_levels[plane] = av1_estimate_noise_from_single_plane(
to_filter_frame, plane, cpi->common.seq_params.bit_depth);
}
// Get quantization factor.
const int q = get_q(cpi);
// Adjust number of filtering frames based on noise and quantization factor.
// Basically, we would like to use more frames to filter low-noise frame such
// that the filtered frame can provide better predictions for more frames.
// Also, when the quantization factor is small enough (lossless compression),
// we will not change the number of frames for key frame filtering, which is
// to avoid visual quality drop.
int adjust_num = 0;
if (num_frames == 1) { // `arnr_max_frames = 1` is used to disable filtering.
adjust_num = 0;
} else if (filter_frame_lookahead_idx < 0 && q <= 10) {
adjust_num = 0;
} else if (noise_levels[0] < 0.5) {
adjust_num = 6;
} else if (noise_levels[0] < 1.0) {
adjust_num = 4;
} else if (noise_levels[0] < 2.0) {
adjust_num = 2;
}
num_frames = AOMMIN(num_frames + adjust_num, lookahead_depth + 1);
if (filter_frame_lookahead_idx == -1 ||
filter_frame_lookahead_idx == 0) { // Key frame.
num_before = 0;
num_after = AOMMIN(num_frames - 1, max_after);
} else if (filter_frame_lookahead_idx < -1) { // Key frame in one-pass mode.
num_before = AOMMIN(num_frames - 1, max_before);
num_after = 0;
} else {
num_frames = AOMMIN(num_frames, cpi->rc.gfu_boost / 150);
num_frames += !(num_frames & 1); // Make the number odd.
// Only use 2 neighbours for the second ARF.
if (is_second_arf) num_frames = AOMMIN(num_frames, 3);
num_before = AOMMIN(num_frames >> 1, max_before);
num_after = AOMMIN(num_frames >> 1, max_after);
}
num_frames = num_before + 1 + num_after;
// Setup the frame buffer.
for (int frame = 0; frame < num_frames; ++frame) {
const int lookahead_idx = frame - num_before + filter_frame_offset;
struct lookahead_entry *buf = av1_lookahead_peek(
cpi->lookahead, lookahead_idx, cpi->compressor_stage);
assert(buf != NULL);
frames[frame] = &buf->img;
}
*num_frames_for_filtering = num_frames;
*filter_frame_idx = num_before;
assert(frames[*filter_frame_idx] == to_filter_frame);
}
/*!\cond */
// A constant number, sqrt(pi / 2), used for noise estimation.
static const double SQRT_PI_BY_2 = 1.25331413732;
double av1_estimate_noise_from_single_plane(const YV12_BUFFER_CONFIG *frame,
const int plane,
const int bit_depth) {
const int is_y_plane = (plane == 0);
const int height = frame->crop_heights[is_y_plane ? 0 : 1];
const int width = frame->crop_widths[is_y_plane ? 0 : 1];
const int stride = frame->strides[is_y_plane ? 0 : 1];
const uint8_t *src = frame->buffers[plane];
const uint16_t *src16 = CONVERT_TO_SHORTPTR(src);
const int is_high_bitdepth = is_frame_high_bitdepth(frame);
int64_t accum = 0;
int count = 0;
for (int i = 1; i < height - 1; ++i) {
for (int j = 1; j < width - 1; ++j) {
// Setup a small 3x3 matrix.
const int center_idx = i * stride + j;
int mat[3][3];
for (int ii = -1; ii <= 1; ++ii) {
for (int jj = -1; jj <= 1; ++jj) {
const int idx = center_idx + ii * stride + jj;
mat[ii + 1][jj + 1] = is_high_bitdepth ? src16[idx] : src[idx];
}
}
// Compute sobel gradients.
const int Gx = (mat[0][0] - mat[0][2]) + (mat[2][0] - mat[2][2]) +
2 * (mat[1][0] - mat[1][2]);
const int Gy = (mat[0][0] - mat[2][0]) + (mat[0][2] - mat[2][2]) +
2 * (mat[0][1] - mat[2][1]);
const int Ga = ROUND_POWER_OF_TWO(abs(Gx) + abs(Gy), bit_depth - 8);
// Accumulate Laplacian.
if (Ga < NOISE_ESTIMATION_EDGE_THRESHOLD) { // Only count smooth pixels.
const int v = 4 * mat[1][1] -
2 * (mat[0][1] + mat[2][1] + mat[1][0] + mat[1][2]) +
(mat[0][0] + mat[0][2] + mat[2][0] + mat[2][2]);
accum += ROUND_POWER_OF_TWO(abs(v), bit_depth - 8);
++count;
}
}
}
// Return -1.0 (unreliable estimation) if there are too few smooth pixels.
return (count < 16) ? -1.0 : (double)accum / (6 * count) * SQRT_PI_BY_2;
}
int av1_temporal_filter(AV1_COMP *cpi, const int filter_frame_lookahead_idx,
int *show_existing_arf) {
// Basic informaton of the current frame.
const GF_GROUP *const gf_group = &cpi->gf_group;
const uint8_t group_idx = gf_group->index;
const FRAME_UPDATE_TYPE update_type = gf_group->update_type[group_idx];
// Filter one more ARF if the lookahead index is leq 7 (w.r.t. 9-th frame).
// This frame is ALWAYS a show existing frame.
const int is_second_arf =
(update_type == INTNL_ARF_UPDATE) && (filter_frame_lookahead_idx >= 7);
// TODO(anyone): Currently, we enforce the filtering strength on internal
// ARFs except the second ARF to be zero. We should investigate in which case
// it is more beneficial to use non-zero strength filtering.
if (update_type == INTNL_ARF_UPDATE && !is_second_arf) {
return 0;
}
// TODO(yunqing): For INTNL_ARF_UPDATE type, the following me initialization
// is used somewhere unexpectedly. Should be resolved later.
// Initialize errorperbit and sadperbit
const int rdmult = av1_compute_rd_mult_based_on_qindex(cpi, TF_QINDEX);
MvCosts *mv_costs = &cpi->td.mb.mv_costs;
av1_set_error_per_bit(mv_costs, rdmult);
av1_set_sad_per_bit(cpi, mv_costs, TF_QINDEX);
av1_fill_mv_costs(cpi->common.fc,
cpi->common.features.cur_frame_force_integer_mv,
cpi->common.features.allow_high_precision_mv, mv_costs);
// Setup frame buffer for filtering.
YV12_BUFFER_CONFIG *frames[MAX_LAG_BUFFERS] = { NULL };
int num_frames_for_filtering = 0;
int filter_frame_idx = -1;
double noise_levels[MAX_MB_PLANE] = { 0 };
tf_setup_filtering_buffer(cpi, filter_frame_lookahead_idx, is_second_arf,
frames, &num_frames_for_filtering,
&filter_frame_idx, noise_levels);
assert(num_frames_for_filtering > 0);
assert(filter_frame_idx < num_frames_for_filtering);
// Set showable frame.
if (filter_frame_lookahead_idx >= 0) {
cpi->common.showable_frame = num_frames_for_filtering == 1 ||
is_second_arf ||
(cpi->oxcf.algo_cfg.enable_overlay == 0);
}
// Do filtering.
// Check show existing condition for non-keyframes. For KFs, only check when
// KF overlay is enabled.
const int check_show_existing =
!(filter_frame_lookahead_idx <= 0) ||
cpi->oxcf.kf_cfg.enable_keyframe_filtering > 1;
// Setup scaling factors. Scaling on each of the arnr frames is not
// supported.
// ARF is produced at the native frame size and resized when coded.
struct scale_factors sf;
av1_setup_scale_factors_for_frame(
&sf, frames[0]->y_crop_width, frames[0]->y_crop_height,
frames[0]->y_crop_width, frames[0]->y_crop_height);
const FRAME_DIFF diff =
tf_do_filtering(cpi, frames, num_frames_for_filtering, filter_frame_idx,
check_show_existing, TF_BLOCK_SIZE, &sf, noise_levels);
if (!check_show_existing) return 1;
if (show_existing_arf != NULL || is_second_arf) {
const int frame_height = frames[filter_frame_idx]->y_crop_height;
const int frame_width = frames[filter_frame_idx]->y_crop_width;
const int block_height = block_size_high[TF_BLOCK_SIZE];
const int block_width = block_size_wide[TF_BLOCK_SIZE];
const int mb_rows = get_num_blocks(frame_height, block_height);
const int mb_cols = get_num_blocks(frame_width, block_width);
const int num_mbs = AOMMAX(1, mb_rows * mb_cols);
const float mean = (float)diff.sum / num_mbs;
const float std = (float)sqrt((float)diff.sse / num_mbs - mean * mean);
aom_clear_system_state();
// TODO(yunqing): This can be combined with TPL q calculation later.
cpi->rc.base_frame_target = gf_group->bit_allocation[group_idx];
av1_set_target_rate(cpi, cpi->common.width, cpi->common.height);
int top_index = 0;
int bottom_index = 0;
const int q = av1_rc_pick_q_and_bounds(
cpi, &cpi->rc, cpi->oxcf.frm_dim_cfg.width,
cpi->oxcf.frm_dim_cfg.height, group_idx, &bottom_index, &top_index);
const int ac_q = av1_ac_quant_QTX(q, 0, cpi->common.seq_params.bit_depth);
const float threshold = 0.7f * ac_q * ac_q;
if (!is_second_arf) {
*show_existing_arf = 0;
if (mean < threshold && std < mean * 1.2) {
*show_existing_arf = 1;
}
cpi->common.showable_frame |= *show_existing_arf;
} else {
// Use source frame if the filtered frame becomes very different.
if (!(mean < threshold && std < mean * 1.2)) {
return 0;
}
}
}
return 1;
}
/*!\endcond */