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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 <limits.h>
#include <math.h>
#include "av1/common/seg_common.h"
#include "av1/encoder/aq_cyclicrefresh.h"
#include "av1/encoder/ratectrl.h"
#include "av1/encoder/segmentation.h"
#include "aom_dsp/aom_dsp_common.h"
#include "aom_ports/system_state.h"
struct CYCLIC_REFRESH {
// Percentage of blocks per frame that are targeted as candidates
// for cyclic refresh.
int percent_refresh;
// Maximum q-delta as percentage of base q.
int max_qdelta_perc;
// Superblock starting index for cycling through the frame.
int sb_index;
// Controls how long block will need to wait to be refreshed again, in
// excess of the cycle time, i.e., in the case of all zero motion, block
// will be refreshed every (100/percent_refresh + time_for_refresh) frames.
int time_for_refresh;
// Target number of (4x4) blocks that are set for delta-q.
int target_num_seg_blocks;
// Actual number of (4x4) blocks that were applied delta-q.
int actual_num_seg1_blocks;
int actual_num_seg2_blocks;
// RD mult. parameters for segment 1.
int rdmult;
// Cyclic refresh map.
int8_t *map;
// Map of the last q a block was coded at.
uint8_t *last_coded_q_map;
// Thresholds applied to the projected rate/distortion of the coding block,
// when deciding whether block should be refreshed.
int64_t thresh_rate_sb;
int64_t thresh_dist_sb;
// Threshold applied to the motion vector (in units of 1/8 pel) of the
// coding block, when deciding whether block should be refreshed.
int16_t motion_thresh;
// Rate target ratio to set q delta.
double rate_ratio_qdelta;
// Boost factor for rate target ratio, for segment CR_SEGMENT_ID_BOOST2.
int rate_boost_fac;
double low_content_avg;
int qindex_delta[3];
double weight_segment;
int apply_cyclic_refresh;
};
CYCLIC_REFRESH *av1_cyclic_refresh_alloc(int mi_rows, int mi_cols) {
size_t last_coded_q_map_size;
CYCLIC_REFRESH *const cr = aom_calloc(1, sizeof(*cr));
if (cr == NULL) return NULL;
cr->map = aom_calloc(mi_rows * mi_cols, sizeof(*cr->map));
if (cr->map == NULL) {
av1_cyclic_refresh_free(cr);
return NULL;
}
last_coded_q_map_size = mi_rows * mi_cols * sizeof(*cr->last_coded_q_map);
cr->last_coded_q_map = aom_malloc(last_coded_q_map_size);
if (cr->last_coded_q_map == NULL) {
av1_cyclic_refresh_free(cr);
return NULL;
}
assert(MAXQ <= 255);
memset(cr->last_coded_q_map, MAXQ, last_coded_q_map_size);
return cr;
}
void av1_cyclic_refresh_free(CYCLIC_REFRESH *cr) {
if (cr != NULL) {
aom_free(cr->map);
aom_free(cr->last_coded_q_map);
aom_free(cr);
}
}
// Check if this coding block, of size bsize, should be considered for refresh
// (lower-qp coding). Decision can be based on various factors, such as
// size of the coding block (i.e., below min_block size rejected), coding
// mode, and rate/distortion.
static int candidate_refresh_aq(const CYCLIC_REFRESH *cr,
const MB_MODE_INFO *mbmi, int64_t rate,
int64_t dist, int bsize) {
MV mv = mbmi->mv[0].as_mv;
// Reject the block for lower-qp coding if projected distortion
// is above the threshold, and any of the following is true:
// 1) mode uses large mv
// 2) mode is an intra-mode
// Otherwise accept for refresh.
if (dist > cr->thresh_dist_sb &&
(mv.row > cr->motion_thresh || mv.row < -cr->motion_thresh ||
mv.col > cr->motion_thresh || mv.col < -cr->motion_thresh ||
!is_inter_block(mbmi)))
return CR_SEGMENT_ID_BASE;
else if (bsize >= BLOCK_16X16 && rate < cr->thresh_rate_sb &&
is_inter_block(mbmi) && mbmi->mv[0].as_int == 0 &&
cr->rate_boost_fac > 10)
// More aggressive delta-q for bigger blocks with zero motion.
return CR_SEGMENT_ID_BOOST2;
else
return CR_SEGMENT_ID_BOOST1;
}
// Compute delta-q for the segment.
static int compute_deltaq(const AV1_COMP *cpi, int q, double rate_factor) {
const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
const RATE_CONTROL *const rc = &cpi->rc;
int deltaq =
av1_compute_qdelta_by_rate(rc, cpi->common.current_frame.frame_type, q,
rate_factor, cpi->common.seq_params.bit_depth);
if ((-deltaq) > cr->max_qdelta_perc * q / 100) {
deltaq = -cr->max_qdelta_perc * q / 100;
}
return deltaq;
}
// For the just encoded frame, estimate the bits, incorporating the delta-q
// from non-base segment. For now ignore effect of multiple segments
// (with different delta-q). Note this function is called in the postencode
// (called from rc_update_rate_correction_factors()).
int av1_cyclic_refresh_estimate_bits_at_q(const AV1_COMP *cpi,
double correction_factor) {
const AV1_COMMON *const cm = &cpi->common;
const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
int estimated_bits;
int mbs = cm->MBs;
int num4x4bl = mbs << 4;
// Weight for non-base segments: use actual number of blocks refreshed in
// previous/just encoded frame. Note number of blocks here is in 4x4 units.
double weight_segment1 = (double)cr->actual_num_seg1_blocks / num4x4bl;
double weight_segment2 = (double)cr->actual_num_seg2_blocks / num4x4bl;
// Take segment weighted average for estimated bits.
estimated_bits =
(int)((1.0 - weight_segment1 - weight_segment2) *
av1_estimate_bits_at_q(cm->current_frame.frame_type,
cm->base_qindex, mbs, correction_factor,
cm->seq_params.bit_depth) +
weight_segment1 * av1_estimate_bits_at_q(
cm->current_frame.frame_type,
cm->base_qindex + cr->qindex_delta[1], mbs,
correction_factor, cm->seq_params.bit_depth) +
weight_segment2 * av1_estimate_bits_at_q(
cm->current_frame.frame_type,
cm->base_qindex + cr->qindex_delta[2], mbs,
correction_factor, cm->seq_params.bit_depth));
return estimated_bits;
}
// Prior to encoding the frame, estimate the bits per mb, for a given q = i and
// a corresponding delta-q (for segment 1). This function is called in the
// rc_regulate_q() to set the base qp index.
// Note: the segment map is set to either 0/CR_SEGMENT_ID_BASE (no refresh) or
// to 1/CR_SEGMENT_ID_BOOST1 (refresh) for each superblock, prior to encoding.
int av1_cyclic_refresh_rc_bits_per_mb(const AV1_COMP *cpi, int i,
double correction_factor) {
const AV1_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
int bits_per_mb;
int num4x4bl = cm->MBs << 4;
// Weight for segment prior to encoding: take the average of the target
// number for the frame to be encoded and the actual from the previous frame.
double weight_segment =
(double)((cr->target_num_seg_blocks + cr->actual_num_seg1_blocks +
cr->actual_num_seg2_blocks) >>
1) /
num4x4bl;
// Compute delta-q corresponding to qindex i.
int deltaq = compute_deltaq(cpi, i, cr->rate_ratio_qdelta);
// Take segment weighted average for bits per mb.
bits_per_mb =
(int)((1.0 - weight_segment) *
av1_rc_bits_per_mb(cm->current_frame.frame_type, i,
correction_factor,
cm->seq_params.bit_depth) +
weight_segment * av1_rc_bits_per_mb(cm->current_frame.frame_type,
i + deltaq, correction_factor,
cm->seq_params.bit_depth));
return bits_per_mb;
}
// Prior to coding a given prediction block, of size bsize at (mi_row, mi_col),
// check if we should reset the segment_id, and update the cyclic_refresh map
// and segmentation map.
void av1_cyclic_refresh_update_segment(const AV1_COMP *cpi,
MB_MODE_INFO *const mbmi, int mi_row,
int mi_col, BLOCK_SIZE bsize,
int64_t rate, int64_t dist, int skip) {
const AV1_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
const int bw = mi_size_wide[bsize];
const int bh = mi_size_high[bsize];
const int xmis = AOMMIN(cm->mi_cols - mi_col, bw);
const int ymis = AOMMIN(cm->mi_rows - mi_row, bh);
const int block_index = mi_row * cm->mi_cols + mi_col;
const int refresh_this_block =
candidate_refresh_aq(cr, mbmi, rate, dist, bsize);
// Default is to not update the refresh map.
int new_map_value = cr->map[block_index];
// If this block is labeled for refresh, check if we should reset the
// segment_id.
if (cyclic_refresh_segment_id_boosted(mbmi->segment_id)) {
mbmi->segment_id = refresh_this_block;
// Reset segment_id if will be skipped.
if (skip) mbmi->segment_id = CR_SEGMENT_ID_BASE;
}
// Update the cyclic refresh map, to be used for setting segmentation map
// for the next frame. If the block will be refreshed this frame, mark it
// as clean. The magnitude of the -ve influences how long before we consider
// it for refresh again.
if (cyclic_refresh_segment_id_boosted(mbmi->segment_id)) {
new_map_value = -cr->time_for_refresh;
} else if (refresh_this_block) {
// Else if it is accepted as candidate for refresh, and has not already
// been refreshed (marked as 1) then mark it as a candidate for cleanup
// for future time (marked as 0), otherwise don't update it.
if (cr->map[block_index] == 1) new_map_value = 0;
} else {
// Leave it marked as block that is not candidate for refresh.
new_map_value = 1;
}
// Update entries in the cyclic refresh map with new_map_value, and
// copy mbmi->segment_id into global segmentation map.
for (int y = 0; y < ymis; y++)
for (int x = 0; x < xmis; x++) {
int map_offset = block_index + y * cm->mi_cols + x;
cr->map[map_offset] = new_map_value;
cpi->segmentation_map[map_offset] = mbmi->segment_id;
}
}
// Update the actual number of blocks that were applied the segment delta q.
void av1_cyclic_refresh_postencode(AV1_COMP *const cpi) {
AV1_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
unsigned char *const seg_map = cpi->segmentation_map;
cr->actual_num_seg1_blocks = 0;
cr->actual_num_seg2_blocks = 0;
for (int mi_row = 0; mi_row < cm->mi_rows; mi_row++)
for (int mi_col = 0; mi_col < cm->mi_cols; mi_col++) {
if (cyclic_refresh_segment_id(seg_map[mi_row * cm->mi_cols + mi_col]) ==
CR_SEGMENT_ID_BOOST1)
cr->actual_num_seg1_blocks++;
else if (cyclic_refresh_segment_id(
seg_map[mi_row * cm->mi_cols + mi_col]) ==
CR_SEGMENT_ID_BOOST2)
cr->actual_num_seg2_blocks++;
}
}
// Set golden frame update interval, for 1 pass CBR mode.
void av1_cyclic_refresh_set_golden_update(AV1_COMP *const cpi) {
RATE_CONTROL *const rc = &cpi->rc;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
// Set minimum gf_interval for GF update to a multiple (== 2) of refresh
// period. Depending on past encoding stats, GF flag may be reset and update
// may not occur until next baseline_gf_interval.
if (cr->percent_refresh > 0)
rc->baseline_gf_interval = 4 * (100 / cr->percent_refresh);
else
rc->baseline_gf_interval = 40;
}
// Update the segmentation map, and related quantities: cyclic refresh map,
// refresh sb_index, and target number of blocks to be refreshed.
// The map is set to either 0/CR_SEGMENT_ID_BASE (no refresh) or to
// 1/CR_SEGMENT_ID_BOOST1 (refresh) for each superblock.
// Blocks labeled as BOOST1 may later get set to BOOST2 (during the
// encoding of the superblock).
static void cyclic_refresh_update_map(AV1_COMP *const cpi) {
AV1_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
unsigned char *const seg_map = cpi->segmentation_map;
int i, block_count, bl_index, sb_rows, sb_cols, sbs_in_frame;
int xmis, ymis, x, y;
memset(seg_map, CR_SEGMENT_ID_BASE, cm->mi_rows * cm->mi_cols);
sb_cols =
(cm->mi_cols + cm->seq_params.mib_size - 1) / cm->seq_params.mib_size;
sb_rows =
(cm->mi_rows + cm->seq_params.mib_size - 1) / cm->seq_params.mib_size;
sbs_in_frame = sb_cols * sb_rows;
// Number of target blocks to get the q delta (segment 1).
block_count = cr->percent_refresh * cm->mi_rows * cm->mi_cols / 100;
// Set the segmentation map: cycle through the superblocks, starting at
// cr->mb_index, and stopping when either block_count blocks have been found
// to be refreshed, or we have passed through whole frame.
if (cr->sb_index >= sbs_in_frame) cr->sb_index = 0;
assert(cr->sb_index < sbs_in_frame);
i = cr->sb_index;
cr->target_num_seg_blocks = 0;
do {
int sum_map = 0;
// Get the mi_row/mi_col corresponding to superblock index i.
int sb_row_index = (i / sb_cols);
int sb_col_index = i - sb_row_index * sb_cols;
int mi_row = sb_row_index * cm->seq_params.mib_size;
int mi_col = sb_col_index * cm->seq_params.mib_size;
int qindex_thresh =
cpi->oxcf.content == AOM_CONTENT_SCREEN
? av1_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST2, cm->base_qindex)
: 0;
assert(mi_row >= 0 && mi_row < cm->mi_rows);
assert(mi_col >= 0 && mi_col < cm->mi_cols);
bl_index = mi_row * cm->mi_cols + mi_col;
// Loop through all MI blocks in superblock and update map.
xmis = AOMMIN(cm->mi_cols - mi_col, cm->seq_params.mib_size);
ymis = AOMMIN(cm->mi_rows - mi_row, cm->seq_params.mib_size);
for (y = 0; y < ymis; y++) {
for (x = 0; x < xmis; x++) {
const int bl_index2 = bl_index + y * cm->mi_cols + x;
// If the block is as a candidate for clean up then mark it
// for possible boost/refresh (segment 1). The segment id may get
// reset to 0 later if block gets coded anything other than GLOBALMV.
if (cr->map[bl_index2] == 0) {
if (cr->last_coded_q_map[bl_index2] > qindex_thresh) sum_map++;
} else if (cr->map[bl_index2] < 0) {
cr->map[bl_index2]++;
}
}
}
// Enforce constant segment over superblock.
// If segment is at least half of superblock, set to 1.
if (sum_map >= xmis * ymis / 2) {
for (y = 0; y < ymis; y++)
for (x = 0; x < xmis; x++) {
seg_map[bl_index + y * cm->mi_cols + x] = CR_SEGMENT_ID_BOOST1;
}
cr->target_num_seg_blocks += xmis * ymis;
}
i++;
if (i == sbs_in_frame) {
i = 0;
}
} while (cr->target_num_seg_blocks < block_count && i != cr->sb_index);
cr->sb_index = i;
}
// Set cyclic refresh parameters.
void av1_cyclic_refresh_update_parameters(AV1_COMP *const cpi) {
// TODO(marpan): Parameters need to be tuned.
const RATE_CONTROL *const rc = &cpi->rc;
const AV1_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
int num4x4bl = cm->MBs << 4;
int target_refresh = 0;
double weight_segment_target = 0;
double weight_segment = 0;
int qp_thresh = AOMMIN(20, rc->best_quality << 1);
cr->apply_cyclic_refresh = 1;
if (frame_is_intra_only(cm) || is_lossless_requested(&cpi->oxcf) ||
rc->avg_frame_qindex[INTER_FRAME] < qp_thresh) {
cr->apply_cyclic_refresh = 0;
return;
}
cr->percent_refresh = 10;
cr->max_qdelta_perc = 60;
cr->time_for_refresh = 0;
cr->motion_thresh = 32;
cr->rate_boost_fac = 15;
// Use larger delta-qp (increase rate_ratio_qdelta) for first few (~4)
// periods of the refresh cycle, after a key frame.
// Account for larger interval on base layer for temporal layers.
if (cr->percent_refresh > 0 &&
rc->frames_since_key < 400 / cr->percent_refresh) {
cr->rate_ratio_qdelta = 3.0;
} else {
cr->rate_ratio_qdelta = 2.0;
}
// Adjust some parameters for low resolutions.
if (cm->width * cm->height <= 352 * 288) {
if (rc->avg_frame_bandwidth < 3000) {
cr->motion_thresh = 16;
cr->rate_boost_fac = 13;
} else {
cr->max_qdelta_perc = 70;
cr->rate_ratio_qdelta = AOMMAX(cr->rate_ratio_qdelta, 2.5);
}
}
if (cpi->oxcf.rc_mode == AOM_VBR) {
// To be adjusted for VBR mode, e.g., based on gf period and boost.
// For now use smaller qp-delta (than CBR), no second boosted seg, and
// turn-off (no refresh) on golden refresh (since it's already boosted).
cr->percent_refresh = 10;
cr->rate_ratio_qdelta = 1.5;
cr->rate_boost_fac = 10;
if (cpi->refresh_golden_frame == 1) {
cr->percent_refresh = 0;
cr->rate_ratio_qdelta = 1.0;
}
}
// Weight for segment prior to encoding: take the average of the target
// number for the frame to be encoded and the actual from the previous frame.
// Use the target if its less. To be used for setting the base qp for the
// frame in vp9_rc_regulate_q.
target_refresh = cr->percent_refresh * cm->mi_rows * cm->mi_cols / 100;
weight_segment_target = (double)(target_refresh) / num4x4bl;
weight_segment = (double)((target_refresh + cr->actual_num_seg1_blocks +
cr->actual_num_seg2_blocks) >>
1) /
num4x4bl;
if (weight_segment_target < 7 * weight_segment / 8)
weight_segment = weight_segment_target;
cr->weight_segment = weight_segment;
}
// Setup cyclic background refresh: set delta q and segmentation map.
void av1_cyclic_refresh_setup(AV1_COMP *const cpi) {
AV1_COMMON *const cm = &cpi->common;
const RATE_CONTROL *const rc = &cpi->rc;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
struct segmentation *const seg = &cm->seg;
int resolution_change =
cm->prev_frame && (cm->width != cm->prev_frame->width ||
cm->height != cm->prev_frame->height);
if (resolution_change) av1_cyclic_refresh_reset_resize(cpi);
if (cm->current_frame.frame_number == 0) cr->low_content_avg = 0.0;
if (!cr->apply_cyclic_refresh) {
// Set segmentation map to 0 and disable.
unsigned char *const seg_map = cpi->segmentation_map;
memset(seg_map, 0, cm->mi_rows * cm->mi_cols);
av1_disable_segmentation(&cm->seg);
if (cm->current_frame.frame_type == KEY_FRAME) {
memset(cr->last_coded_q_map, MAXQ,
cm->mi_rows * cm->mi_cols * sizeof(*cr->last_coded_q_map));
cr->sb_index = 0;
}
return;
} else {
const double q =
av1_convert_qindex_to_q(cm->base_qindex, cm->seq_params.bit_depth);
aom_clear_system_state();
// Set rate threshold to some multiple (set to 2 for now) of the target
// rate (target is given by sb64_target_rate and scaled by 256).
cr->thresh_rate_sb = ((int64_t)(rc->sb64_target_rate) << 8) << 2;
// Distortion threshold, quadratic in Q, scale factor to be adjusted.
// q will not exceed 457, so (q * q) is within 32bit; see:
// av1_convert_qindex_to_q(), av1_ac_quant(), ac_qlookup*[].
cr->thresh_dist_sb = ((int64_t)(q * q)) << 2;
// Set up segmentation.
// Clear down the segment map.
av1_enable_segmentation(&cm->seg);
av1_clearall_segfeatures(seg);
// Note: setting temporal_update has no effect, as the seg-map coding method
// (temporal or spatial) is determined in
// av1_choose_segmap_coding_method(),
// based on the coding cost of each method. For error_resilient mode on the
// last_frame_seg_map is set to 0, so if temporal coding is used, it is
// relative to 0 previous map.
// seg->temporal_update = 0;
// Segment BASE "Q" feature is disabled so it defaults to the baseline Q.
av1_disable_segfeature(seg, CR_SEGMENT_ID_BASE, SEG_LVL_ALT_Q);
// Use segment BOOST1 for in-frame Q adjustment.
av1_enable_segfeature(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q);
// Use segment BOOST2 for more aggressive in-frame Q adjustment.
av1_enable_segfeature(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q);
// Set the q delta for segment BOOST1.
int qindex_delta =
compute_deltaq(cpi, cm->base_qindex, cr->rate_ratio_qdelta);
cr->qindex_delta[1] = qindex_delta;
// Compute rd-mult for segment BOOST1.
const int qindex2 =
clamp(cm->base_qindex + cm->y_dc_delta_q + qindex_delta, 0, MAXQ);
cr->rdmult = av1_compute_rd_mult(cpi, qindex2);
av1_set_segdata(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q, qindex_delta);
// Set a more aggressive (higher) q delta for segment BOOST2.
qindex_delta = compute_deltaq(
cpi, cm->base_qindex,
AOMMIN(CR_MAX_RATE_TARGET_RATIO,
0.1 * cr->rate_boost_fac * cr->rate_ratio_qdelta));
cr->qindex_delta[2] = qindex_delta;
av1_set_segdata(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q, qindex_delta);
// Update the segmentation and refresh map.
cyclic_refresh_update_map(cpi);
}
}
int av1_cyclic_refresh_get_rdmult(const CYCLIC_REFRESH *cr) {
return cr->rdmult;
}
void av1_cyclic_refresh_reset_resize(AV1_COMP *const cpi) {
const AV1_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
memset(cr->map, 0, cm->mi_rows * cm->mi_cols);
cr->sb_index = 0;
cpi->refresh_golden_frame = 1;
}