Commit 83fd1897 authored by Marco Paniconi's avatar Marco Paniconi Committed by Marco
Browse files

Cyclic refresh: factor segment delta-q into rate control.

Incorporate segment delta-q into estimated bits.
This generally improves the rate control under cyclic refresh (aq=3) mode.

Change-Id: I1dc60fb230e7d08357fae18909d8ed27bf58e037
parent f59cb45e
......@@ -19,21 +19,23 @@
#include "vp9/encoder/vp9_segmentation.h"
struct CYCLIC_REFRESH {
// Percentage of super-blocks per frame that are targeted as candidates
// Percentage of blocks per frame that are targeted as candidates
// for cyclic refresh.
int max_sbs_perframe;
int percent_refresh;
// Maximum q-delta as percentage of base q.
int max_qdelta_perc;
// Block size below which we don't apply cyclic refresh.
BLOCK_SIZE min_block_size;
// Superblock starting index for cycling through the frame.
int sb_index;
// Controls how long a block will need to wait to be refreshed again.
// 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 (8x8) blocks that are set for delta-q (segment 1).
int target_num_seg_blocks;
// Actual number of (8x8) blocks that were applied delta-q (segment 1).
int num_seg_blocks;
// Actual encoding bits for segment 1.
int actual_seg_bits;
int actual_num_seg_blocks;
// RD mult. parameters for segment 1.
int rdmult;
// Cyclic refresh map.
......@@ -41,6 +43,8 @@ struct CYCLIC_REFRESH {
// Thresholds applied to projected rate/distortion of the superblock.
int64_t thresh_rate_sb;
int64_t thresh_dist_sb;
// Rate target ratio to set q delta.
double rate_ratio_qdelta;
};
CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols) {
......@@ -117,6 +121,73 @@ static int candidate_refresh_aq(const CYCLIC_REFRESH *cr,
}
}
// Compute delta-q for the segment.
static int compute_deltaq(const VP9_COMP *cpi, int q) {
const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
const RATE_CONTROL *const rc = &cpi->rc;
int deltaq = vp9_compute_qdelta_by_rate(rc, cpi->common.frame_type,
q, cr->rate_ratio_qdelta,
cpi->common.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 segment 1. This function is called in the postencode (called from
// rc_update_rate_correction_factors()).
int vp9_cyclic_refresh_estimate_bits_at_q(const VP9_COMP *cpi,
double correction_factor) {
const VP9_COMMON *const cm = &cpi->common;
const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
int estimated_bits;
int mbs = cm->MBs;
int num8x8bl = mbs << 2;
// Weight for segment 1: use actual number of blocks refreshed in
// previous/just encoded frame. Note number of blocks here is in 8x8 units.
double weight_segment = (double)cr->actual_num_seg_blocks / num8x8bl;
// Compute delta-q that was used in the just encoded frame.
int deltaq = compute_deltaq(cpi, cm->base_qindex);
// Take segment weighted average for estimated bits.
estimated_bits = (int)((1.0 - weight_segment) *
vp9_estimate_bits_at_q(cm->frame_type, cm->base_qindex, mbs,
correction_factor, cm->bit_depth) +
weight_segment *
vp9_estimate_bits_at_q(cm->frame_type, cm->base_qindex + deltaq, mbs,
correction_factor, cm->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.
int vp9_cyclic_refresh_rc_bits_per_mb(const VP9_COMP *cpi, int i,
double correction_factor) {
const VP9_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
int bits_per_mb;
int num8x8bl = cm->MBs << 2;
// Weight for segment 1 prior to encoding: take the target number for the
// frame to be encoded. Number of blocks here is in 8x8 units.
// Note that this is called in rc_regulate_q, which is called before the
// cyclic_refresh_setup (which sets cr->target_num_seg_blocks). So a mismatch
// may occur between the cr->target_num_seg_blocks value here and the
// cr->target_num_seg_block set for encoding the frame. For the current use
// case of fixed cr->percent_refresh and cr->time_for_refresh = 0, mismatch
// does not occur/is very small.
double weight_segment = (double)cr->target_num_seg_blocks / num8x8bl;
// Compute delta-q corresponding to qindex i.
int deltaq = compute_deltaq(cpi, i);
// Take segment weighted average for bits per mb.
bits_per_mb = (int)((1.0 - weight_segment) *
vp9_rc_bits_per_mb(cm->frame_type, i, correction_factor, cm->bit_depth) +
weight_segment *
vp9_rc_bits_per_mb(cm->frame_type, i + deltaq, correction_factor,
cm->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.
......@@ -167,10 +238,85 @@ void vp9_cyclic_refresh_update_segment(VP9_COMP *const cpi,
cpi->segmentation_map[block_index + y * cm->mi_cols + x] =
mbmi->segment_id;
}
// Keep track of actual number (in units of 8x8) of blocks in segment 1 used
// for encoding this frame.
if (mbmi->segment_id)
cr->num_seg_blocks += xmis * ymis;
}
// Update the actual number of blocks that were applied the segment delta q.
void vp9_cyclic_refresh_update_actual_count(struct VP9_COMP *const cpi) {
VP9_COMMON *const cm = &cpi->common;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
unsigned char *const seg_map = cpi->segmentation_map;
int mi_row, mi_col;
cr->actual_num_seg_blocks = 0;
for (mi_row = 0; mi_row < cm->mi_rows; mi_row++)
for (mi_col = 0; mi_col < cm->mi_cols; mi_col++) {
if (seg_map[mi_row * cm->mi_cols + mi_col] == 1)
cr->actual_num_seg_blocks++;
}
}
// Update the segmentation map, and related quantities: cyclic refresh map,
// refresh sb_index, and target number of blocks to be refreshed.
void vp9_cyclic_refresh_update_map(VP9_COMP *const cpi) {
VP9_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;
vpx_memset(seg_map, 0, cm->mi_rows * cm->mi_cols);
sb_cols = (cm->mi_cols + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
sb_rows = (cm->mi_rows + MI_BLOCK_SIZE - 1) / MI_BLOCK_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.
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 * MI_BLOCK_SIZE;
int mi_col = sb_col_index * MI_BLOCK_SIZE;
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 8x8 blocks in superblock and update map.
xmis = MIN(cm->mi_cols - mi_col,
num_8x8_blocks_wide_lookup[BLOCK_64X64]);
ymis = MIN(cm->mi_rows - mi_row,
num_8x8_blocks_high_lookup[BLOCK_64X64]);
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 ZEROMV.
if (cr->map[bl_index2] == 0) {
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] = 1;
}
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;
}
// Setup cyclic background refresh: set delta q and segmentation map.
......@@ -179,7 +325,6 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) {
const RATE_CONTROL *const rc = &cpi->rc;
CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
struct segmentation *const seg = &cm->seg;
unsigned char *const seg_map = cpi->segmentation_map;
const int apply_cyclic_refresh = apply_cyclic_refresh_bitrate(cm, rc);
// Don't apply refresh on key frame or enhancement layer frames.
if (!apply_cyclic_refresh ||
......@@ -187,6 +332,7 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) {
(cpi->svc.temporal_layer_id > 0) ||
(cpi->svc.spatial_layer_id > 0)) {
// Set segmentation map to 0 and disable.
unsigned char *const seg_map = cpi->segmentation_map;
vpx_memset(seg_map, 0, cm->mi_rows * cm->mi_cols);
vp9_disable_segmentation(&cm->seg);
if (cm->frame_type == KEY_FRAME)
......@@ -194,18 +340,15 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) {
return;
} else {
int qindex_delta = 0;
int i, block_count, bl_index, sb_rows, sb_cols, sbs_in_frame;
int xmis, ymis, x, y, qindex2;
// Rate target ratio to set q delta.
const float rate_ratio_qdelta = 2.0;
int qindex2;
const double q = vp9_convert_qindex_to_q(cm->base_qindex, cm->bit_depth);
vp9_clear_system_state();
// Some of these parameters may be set via codec-control function later.
cr->max_sbs_perframe = 10;
cr->percent_refresh = 10;
cr->rate_ratio_qdelta = 2.0;
cr->max_qdelta_perc = 50;
cr->min_block_size = BLOCK_8X8;
cr->time_for_refresh = 1;
cr->time_for_refresh = 0;
// Set rate threshold to some fraction of target (and scaled by 256).
cr->thresh_rate_sb = (rc->sb64_target_rate * 256) >> 2;
// Distortion threshold, quadratic in Q, scale factor to be adjusted.
......@@ -217,10 +360,8 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) {
cr->thresh_dist_sb = 16 * (int)(q * q);
}
cr->num_seg_blocks = 0;
// Set up segmentation.
// Clear down the segment map.
vpx_memset(seg_map, 0, cm->mi_rows * cm->mi_cols);
vp9_enable_segmentation(&cm->seg);
vp9_clearall_segfeatures(seg);
// Select delta coding method.
......@@ -239,14 +380,7 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) {
vp9_enable_segfeature(seg, 1, SEG_LVL_ALT_Q);
// Set the q delta for segment 1.
qindex_delta = vp9_compute_qdelta_by_rate(rc, cm->frame_type,
cm->base_qindex,
rate_ratio_qdelta,
cm->bit_depth);
// TODO(marpan): Incorporate the actual-vs-target rate over/undershoot from
// previous encoded frame.
if (-qindex_delta > cr->max_qdelta_perc * cm->base_qindex / 100)
qindex_delta = -cr->max_qdelta_perc * cm->base_qindex / 100;
qindex_delta = compute_deltaq(cpi, cm->base_qindex);
// Compute rd-mult for segment 1.
qindex2 = clamp(cm->base_qindex + cm->y_dc_delta_q + qindex_delta, 0, MAXQ);
......@@ -254,61 +388,8 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) {
vp9_set_segdata(seg, 1, SEG_LVL_ALT_Q, qindex_delta);
sb_cols = (cm->mi_cols + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
sb_rows = (cm->mi_rows + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
sbs_in_frame = sb_cols * sb_rows;
// Number of target superblocks to get the q delta (segment 1).
block_count = cr->max_sbs_perframe * sbs_in_frame / 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.
assert(cr->sb_index < sbs_in_frame);
i = cr->sb_index;
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 * MI_BLOCK_SIZE;
int mi_col = sb_col_index * MI_BLOCK_SIZE;
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 8x8 blocks in superblock and update map.
xmis = MIN(cm->mi_cols - mi_col,
num_8x8_blocks_wide_lookup[BLOCK_64X64]);
ymis = MIN(cm->mi_rows - mi_row,
num_8x8_blocks_high_lookup[BLOCK_64X64]);
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 ZEROMV.
if (cr->map[bl_index2] == 0) {
seg_map[bl_index2] = 1;
sum_map++;
} else if (cr->map[bl_index2] < 0) {
cr->map[bl_index2]++;
}
}
}
// Enforce constant segment over superblock.
// If segment is partial over superblock, reset to either all 1 or 0.
if (sum_map > 0 && sum_map < xmis * ymis) {
const int new_value = (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] = new_value;
}
i++;
if (i == sbs_in_frame) {
i = 0;
}
if (sum_map >= xmis * ymis /2)
block_count--;
} while (block_count && i != cr->sb_index);
cr->sb_index = i;
// Update the segmentation and refresh map.
vp9_cyclic_refresh_update_map(cpi);
}
}
......
......@@ -27,6 +27,16 @@ CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols);
void vp9_cyclic_refresh_free(CYCLIC_REFRESH *cr);
// Estimate the bits, incorporating the delta-q from segment 1, after encoding
// the frame.
int vp9_cyclic_refresh_estimate_bits_at_q(const struct VP9_COMP *cpi,
double correction_factor);
// Estimate the bits per mb, for a given q = i and a corresponding delta-q
// (for segment 1), prior to encoding the frame.
int vp9_cyclic_refresh_rc_bits_per_mb(const struct VP9_COMP *cpi, int i,
double correction_factor);
// 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.
......@@ -36,6 +46,13 @@ void vp9_cyclic_refresh_update_segment(struct VP9_COMP *const cpi,
BLOCK_SIZE bsize, int use_rd,
int64_t rate_sb);
// Update the segmentation map, and related quantities: cyclic refresh map,
// refresh sb_index, and target number of blocks to be refreshed.
void vp9_cyclic_refresh_update__map(struct VP9_COMP *const cpi);
// Update the actual number of blocks that were applied the segment delta q.
void vp9_cyclic_refresh_update_actual_count(struct VP9_COMP *const cpi);
// Setup cyclic background refresh: set delta q and segmentation map.
void vp9_cyclic_refresh_setup(struct VP9_COMP *const cpi);
......
......@@ -18,6 +18,7 @@
#include "vpx_mem/vpx_mem.h"
#include "vp9/common/vp9_alloccommon.h"
#include "vp9/encoder/vp9_aq_cyclicrefresh.h"
#include "vp9/common/vp9_common.h"
#include "vp9/common/vp9_entropymode.h"
#include "vp9/common/vp9_quant_common.h"
......@@ -185,9 +186,9 @@ int vp9_rc_bits_per_mb(FRAME_TYPE frame_type, int qindex,
return (int)(enumerator * correction_factor / q);
}
static int estimate_bits_at_q(FRAME_TYPE frame_type, int q, int mbs,
double correction_factor,
vpx_bit_depth_t bit_depth) {
int vp9_estimate_bits_at_q(FRAME_TYPE frame_type, int q, int mbs,
double correction_factor,
vpx_bit_depth_t bit_depth) {
const int bpm = (int)(vp9_rc_bits_per_mb(frame_type, q, correction_factor,
bit_depth));
return MAX(FRAME_OVERHEAD_BITS,
......@@ -232,7 +233,6 @@ int vp9_rc_clamp_iframe_target_size(const VP9_COMP *const cpi, int target) {
return target;
}
// Update the buffer level for higher layers, given the encoded current layer.
static void update_layer_buffer_level(SVC *svc, int encoded_frame_size) {
int temporal_layer = 0;
......@@ -414,10 +414,16 @@ void vp9_rc_update_rate_correction_factors(VP9_COMP *cpi, int damp_var) {
// Work out how big we would have expected the frame to be at this Q given
// the current correction factor.
// Stay in double to avoid int overflow when values are large
projected_size_based_on_q = estimate_bits_at_q(cm->frame_type,
cm->base_qindex, cm->MBs,
rate_correction_factor,
cm->bit_depth);
if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ && cpi->common.seg.enabled) {
projected_size_based_on_q =
vp9_cyclic_refresh_estimate_bits_at_q(cpi, rate_correction_factor);
} else {
projected_size_based_on_q = vp9_estimate_bits_at_q(cpi->common.frame_type,
cm->base_qindex,
cm->MBs,
rate_correction_factor,
cm->bit_depth);
}
// Work out a size correction factor.
if (projected_size_based_on_q > FRAME_OVERHEAD_BITS)
correction_factor = (100 * cpi->rc.projected_frame_size) /
......@@ -477,7 +483,7 @@ int vp9_rc_regulate_q(const VP9_COMP *cpi, int target_bits_per_frame,
const VP9_COMMON *const cm = &cpi->common;
int q = active_worst_quality;
int last_error = INT_MAX;
int i, target_bits_per_mb;
int i, target_bits_per_mb, bits_per_mb_at_this_q;
const double correction_factor = get_rate_correction_factor(cpi);
// Calculate required scaling factor based on target frame size and size of
......@@ -488,9 +494,14 @@ int vp9_rc_regulate_q(const VP9_COMP *cpi, int target_bits_per_frame,
i = active_best_quality;
do {
const int bits_per_mb_at_this_q = (int)vp9_rc_bits_per_mb(cm->frame_type, i,
correction_factor,
cm->bit_depth);
if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ && cm->seg.enabled) {
bits_per_mb_at_this_q =
(int)vp9_cyclic_refresh_rc_bits_per_mb(cpi, i, correction_factor);
} else {
bits_per_mb_at_this_q = (int)vp9_rc_bits_per_mb(cm->frame_type, i,
correction_factor,
cm->bit_depth);
}
if (bits_per_mb_at_this_q <= target_bits_per_mb) {
if ((target_bits_per_mb - bits_per_mb_at_this_q) <= last_error)
......@@ -1203,6 +1214,10 @@ void vp9_rc_postencode_update(VP9_COMP *cpi, uint64_t bytes_used) {
RATE_CONTROL *const rc = &cpi->rc;
const int qindex = cm->base_qindex;
if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ && cm->seg.enabled) {
vp9_cyclic_refresh_update_actual_count(cpi);
}
// Update rate control heuristics
rc->projected_frame_size = (int)(bytes_used << 3);
......
......@@ -115,6 +115,10 @@ struct VP9EncoderConfig;
void vp9_rc_init(const struct VP9EncoderConfig *oxcf, int pass,
RATE_CONTROL *rc);
int vp9_estimate_bits_at_q(FRAME_TYPE frame_kind, int q, int mbs,
double correction_factor,
vpx_bit_depth_t bit_depth);
double vp9_convert_qindex_to_q(int qindex, vpx_bit_depth_t bit_depth);
void vp9_rc_init_minq_luts();
......
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