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vpx/vp9/encoder/vp9_quantize.c
Yunqing Wang b5bf7b13a8 Add two-pass quantization 
Optimized the quantization function by making it a two-pass
process. The first pass does a quick checking of the transform
coefficients against the base ZBIN, and only keep the good
enough set of coefficients for quantization. A skipping
check is added. If all coefficients are within the base ZBIN, no
quantization is needed. The second pass is the actual quantization
pass, which only processes the coefficient subset determined
in first pass. This reduces the computation. Furthermore, an
alternitive method is used for large transform size, which often
has sparse nonzero quantized coefficients.

Overall, the encoder speedup is about 4%. The quantization function
itself gets 20% faster.

Change-Id: I3a9dd0da6db030260b6d9c314a9fa48ecae89f22
2013-06-19 10:35:02 -07:00

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/*
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include <math.h>
#include "vpx_mem/vpx_mem.h"
#include "vp9/encoder/vp9_onyx_int.h"
#include "vp9/encoder/vp9_quantize.h"
#include "vp9/common/vp9_quant_common.h"
#include "vp9/common/vp9_seg_common.h"
#ifdef ENC_DEBUG
extern int enc_debug;
#endif
static INLINE int plane_idx(int plane) {
return plane == 0 ? 0 :
plane == 1 ? 16 : 20;
}
static void quantize(int16_t *zbin_boost_orig_ptr,
int16_t *coeff_ptr, int n_coeffs, int skip_block,
int16_t *zbin_ptr, int16_t *round_ptr, int16_t *quant_ptr,
uint8_t *quant_shift_ptr,
int16_t *qcoeff_ptr, int16_t *dqcoeff_ptr,
int16_t *dequant_ptr, int zbin_oq_value,
uint16_t *eob_ptr,
const int *scan, int mul) {
int i, rc, eob;
int zbins[2], nzbins[2], zbin;
int x, y, z, sz;
int zero_run = 0;
int16_t *zbin_boost_ptr = zbin_boost_orig_ptr;
int zero_flag = n_coeffs;
vpx_memset(qcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
vpx_memset(dqcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
eob = -1;
// Base ZBIN
zbins[0] = zbin_ptr[0] + zbin_oq_value;
zbins[1] = zbin_ptr[1] + zbin_oq_value;
nzbins[0] = zbins[0] * -1;
nzbins[1] = zbins[1] * -1;
if (!skip_block) {
// Pre-scan pass
for (i = n_coeffs - 1; i >= 0; i--) {
rc = scan[i];
z = coeff_ptr[rc] * mul;
if (z < zbins[rc != 0] && z > nzbins[rc != 0]) {
zero_flag--;
} else {
break;
}
}
// Quantization pass: All coefficients with index >= zero_flag are
// skippable. Note: zero_flag can be zero.
for (i = 0; i < zero_flag; i++) {
rc = scan[i];
z = coeff_ptr[rc] * mul;
zbin = (zbins[rc != 0] + zbin_boost_ptr[zero_run]);
zero_run += (zero_run < 15);
sz = (z >> 31); // sign of z
x = (z ^ sz) - sz;
if (x >= zbin) {
x += (round_ptr[rc != 0]);
y = ((int)(((int)(x * quant_ptr[rc != 0]) >> 16) + x))
>> quant_shift_ptr[rc != 0]; // quantize (x)
x = (y ^ sz) - sz; // get the sign back
qcoeff_ptr[rc] = x; // write to destination
dqcoeff_ptr[rc] = x * dequant_ptr[rc != 0] / mul; // dequantized value
if (y) {
eob = i; // last nonzero coeffs
zero_run = 0; // set zero_run
}
}
}
}
*eob_ptr = eob + 1;
}
// This function works well for large transform size.
static void quantize_sparse(int16_t *zbin_boost_orig_ptr,
int16_t *coeff_ptr, int n_coeffs, int skip_block,
int16_t *zbin_ptr, int16_t *round_ptr,
int16_t *quant_ptr, uint8_t *quant_shift_ptr,
int16_t *qcoeff_ptr, int16_t *dqcoeff_ptr,
int16_t *dequant_ptr, int zbin_oq_value,
uint16_t *eob_ptr, const int *scan, int mul,
int *idx_arr) {
int i, rc, eob;
int zbins[2], pzbins[2], nzbins[2], zbin;
int x, y, z, sz;
int zero_run = 0;
int16_t *zbin_boost_ptr = zbin_boost_orig_ptr;
int idx = 0;
int pre_idx = 0;
vpx_memset(qcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
vpx_memset(dqcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
eob = -1;
// Base ZBIN
zbins[0] = zbin_ptr[0] + zbin_oq_value;
zbins[1] = zbin_ptr[1] + zbin_oq_value;
// Positive and negative ZBIN
pzbins[0] = zbins[0]/mul;
pzbins[1] = zbins[1]/mul;
nzbins[0] = pzbins[0] * -1;
nzbins[1] = pzbins[1] * -1;
if (!skip_block) {
// Pre-scan pass
for (i = 0; i < n_coeffs; i++) {
rc = scan[i];
z = coeff_ptr[rc];
// If the coefficient is out of the base ZBIN range, keep it for
// quantization.
if (z >= pzbins[rc != 0] || z <= nzbins[rc != 0])
idx_arr[idx++] = i;
}
// Quantization pass: only process the coefficients selected in
// pre-scan pass. Note: idx can be zero.
for (i = 0; i < idx; i++) {
rc = scan[idx_arr[i]];
// Calculate ZBIN
zero_run += idx_arr[i] - pre_idx;
if(zero_run > 15) zero_run = 15;
zbin = (zbins[rc != 0] + zbin_boost_ptr[zero_run]);
pre_idx = idx_arr[i];
z = coeff_ptr[rc] * mul;
sz = (z >> 31); // sign of z
x = (z ^ sz) - sz; // x = abs(z)
if (x >= zbin) {
x += (round_ptr[rc != 0]);
y = ((int)(((int)(x * quant_ptr[rc != 0]) >> 16) + x))
>> quant_shift_ptr[rc != 0]; // quantize (x)
x = (y ^ sz) - sz; // get the sign back
qcoeff_ptr[rc] = x; // write to destination
dqcoeff_ptr[rc] = x * dequant_ptr[rc != 0] / mul; // dequantized value
if (y) {
eob = idx_arr[i]; // last nonzero coeffs
zero_run = -1; // set zero_run
}
}
}
}
*eob_ptr = eob + 1;
}
#if 0
// Original quantize function
static void quantize(int16_t *zbin_boost_orig_ptr,
int16_t *coeff_ptr, int n_coeffs, int skip_block,
int16_t *zbin_ptr, int16_t *round_ptr, int16_t *quant_ptr,
uint8_t *quant_shift_ptr,
int16_t *qcoeff_ptr, int16_t *dqcoeff_ptr,
int16_t *dequant_ptr, int zbin_oq_value,
uint16_t *eob_ptr,
const int *scan, int mul) {
int i, rc, eob;
int zbin;
int x, y, z, sz;
int zero_run = 0;
int16_t *zbin_boost_ptr = zbin_boost_orig_ptr;
vpx_memset(qcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
vpx_memset(dqcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
eob = -1;
if (!skip_block) {
for (i = 0; i < n_coeffs; i++) {
rc = scan[i];
z = coeff_ptr[rc] * mul;
zbin = (zbin_ptr[rc != 0] + zbin_boost_ptr[zero_run] + zbin_oq_value);
zero_run += (zero_run < 15);
sz = (z >> 31); // sign of z
x = (z ^ sz) - sz; // x = abs(z)
if (x >= zbin) {
x += (round_ptr[rc != 0]);
y = ((int)(((int)(x * quant_ptr[rc != 0]) >> 16) + x))
>> quant_shift_ptr[rc != 0]; // quantize (x)
x = (y ^ sz) - sz; // get the sign back
qcoeff_ptr[rc] = x; // write to destination
dqcoeff_ptr[rc] = x * dequant_ptr[rc != 0] / mul; // dequantized value
if (y) {
eob = i; // last nonzero coeffs
zero_run = 0;
}
}
}
}
*eob_ptr = eob + 1;
}
#endif
void vp9_quantize(MACROBLOCK *mb, int plane, int block, int n_coeffs,
TX_TYPE tx_type) {
MACROBLOCKD *const xd = &mb->e_mbd;
const int mul = n_coeffs == 1024 ? 2 : 1;
const int *scan;
// These contexts may be available in the caller
switch (n_coeffs) {
case 4 * 4:
scan = get_scan_4x4(tx_type);
break;
case 8 * 8:
scan = get_scan_8x8(tx_type);
break;
case 16 * 16:
scan = get_scan_16x16(tx_type);
break;
default:
scan = vp9_default_scan_32x32;
break;
}
// Call different quantization for different transform size.
if (n_coeffs >= 1024) {
// Save index of picked coefficient in pre-scan pass.
int idx_arr[1024];
quantize_sparse(mb->plane[plane].zrun_zbin_boost,
BLOCK_OFFSET(mb->plane[plane].coeff, block, 16),
n_coeffs, mb->skip_block,
mb->plane[plane].zbin,
mb->plane[plane].round,
mb->plane[plane].quant,
mb->plane[plane].quant_shift,
BLOCK_OFFSET(xd->plane[plane].qcoeff, block, 16),
BLOCK_OFFSET(xd->plane[plane].dqcoeff, block, 16),
xd->plane[plane].dequant,
mb->plane[plane].zbin_extra,
&xd->plane[plane].eobs[block],
scan, mul, idx_arr);
}
else {
quantize(mb->plane[plane].zrun_zbin_boost,
BLOCK_OFFSET(mb->plane[plane].coeff, block, 16),
n_coeffs, mb->skip_block,
mb->plane[plane].zbin,
mb->plane[plane].round,
mb->plane[plane].quant,
mb->plane[plane].quant_shift,
BLOCK_OFFSET(xd->plane[plane].qcoeff, block, 16),
BLOCK_OFFSET(xd->plane[plane].dqcoeff, block, 16),
xd->plane[plane].dequant,
mb->plane[plane].zbin_extra,
&xd->plane[plane].eobs[block],
scan, mul);
}
}
void vp9_regular_quantize_b_4x4(MACROBLOCK *mb, int b_idx, TX_TYPE tx_type,
int y_blocks) {
MACROBLOCKD *const xd = &mb->e_mbd;
const struct plane_block_idx pb_idx = plane_block_idx(y_blocks, b_idx);
const int *pt_scan = get_scan_4x4(tx_type);
quantize(mb->plane[pb_idx.plane].zrun_zbin_boost,
BLOCK_OFFSET(mb->plane[pb_idx.plane].coeff, pb_idx.block, 16),
16, mb->skip_block,
mb->plane[pb_idx.plane].zbin,
mb->plane[pb_idx.plane].round,
mb->plane[pb_idx.plane].quant,
mb->plane[pb_idx.plane].quant_shift,
BLOCK_OFFSET(xd->plane[pb_idx.plane].qcoeff, pb_idx.block, 16),
BLOCK_OFFSET(xd->plane[pb_idx.plane].dqcoeff, pb_idx.block, 16),
xd->plane[pb_idx.plane].dequant,
mb->plane[pb_idx.plane].zbin_extra,
&xd->plane[pb_idx.plane].eobs[pb_idx.block],
pt_scan, 1);
}
static void invert_quant(int16_t *quant, uint8_t *shift, int d) {
unsigned t;
int l;
t = d;
for (l = 0; t > 1; l++)
t >>= 1;
t = 1 + (1 << (16 + l)) / d;
*quant = (int16_t)(t - (1 << 16));
*shift = l;
}
void vp9_init_quantizer(VP9_COMP *cpi) {
int i;
int quant_val;
int quant_uv_val;
#if CONFIG_ALPHA
int quant_alpha_val;
#endif
int q;
static const int zbin_boost[16] = { 0, 0, 0, 8, 8, 8, 10, 12,
14, 16, 20, 24, 28, 32, 36, 40 };
for (q = 0; q < QINDEX_RANGE; q++) {
int qzbin_factor = (vp9_dc_quant(q, 0) < 148) ? 84 : 80;
int qrounding_factor = 48;
if (q == 0) {
qzbin_factor = 64;
qrounding_factor = 64;
}
// dc values
quant_val = vp9_dc_quant(q, cpi->common.y_dc_delta_q);
invert_quant(cpi->y_quant[q] + 0, cpi->y_quant_shift[q] + 0, quant_val);
cpi->y_zbin[q][0] = ROUND_POWER_OF_TWO(qzbin_factor * quant_val, 7);
cpi->y_round[q][0] = (qrounding_factor * quant_val) >> 7;
cpi->common.y_dequant[q][0] = quant_val;
cpi->zrun_zbin_boost_y[q][0] = (quant_val * zbin_boost[0]) >> 7;
quant_val = vp9_dc_quant(q, cpi->common.uv_dc_delta_q);
invert_quant(cpi->uv_quant[q] + 0, cpi->uv_quant_shift[q] + 0, quant_val);
cpi->uv_zbin[q][0] = ROUND_POWER_OF_TWO(qzbin_factor * quant_val, 7);
cpi->uv_round[q][0] = (qrounding_factor * quant_val) >> 7;
cpi->common.uv_dequant[q][0] = quant_val;
cpi->zrun_zbin_boost_uv[q][0] = (quant_val * zbin_boost[0]) >> 7;
#if CONFIG_ALPHA
quant_val = vp9_dc_quant(q, cpi->common.a_dc_delta_q);
invert_quant(cpi->a_quant[q] + 0, cpi->a_quant_shift[q] + 0, quant_val);
cpi->a_zbin[q][0] = ROUND_POWER_OF_TWO(qzbin_factor * quant_val, 7);
cpi->a_round[q][0] = (qrounding_factor * quant_val) >> 7;
cpi->common.a_dequant[q][0] = quant_val;
cpi->zrun_zbin_boost_a[q][0] = (quant_val * zbin_boost[0]) >> 7;
#endif
quant_val = vp9_ac_quant(q, 0);
cpi->common.y_dequant[q][1] = quant_val;
quant_uv_val = vp9_ac_quant(q, cpi->common.uv_ac_delta_q);
cpi->common.uv_dequant[q][1] = quant_uv_val;
#if CONFIG_ALPHA
quant_alpha_val = vp9_ac_quant(q, cpi->common.a_ac_delta_q);
cpi->common.a_dequant[q][1] = quant_alpha_val;
#endif
// all the 4x4 ac values =;
for (i = 1; i < 16; i++) {
int rc = vp9_default_scan_4x4[i];
invert_quant(cpi->y_quant[q] + rc, cpi->y_quant_shift[q] + rc, quant_val);
cpi->y_zbin[q][rc] = ROUND_POWER_OF_TWO(qzbin_factor * quant_val, 7);
cpi->y_round[q][rc] = (qrounding_factor * quant_val) >> 7;
cpi->zrun_zbin_boost_y[q][i] =
ROUND_POWER_OF_TWO(quant_val * zbin_boost[i], 7);
invert_quant(cpi->uv_quant[q] + rc, cpi->uv_quant_shift[q] + rc,
quant_uv_val);
cpi->uv_zbin[q][rc] = ROUND_POWER_OF_TWO(qzbin_factor * quant_uv_val, 7);
cpi->uv_round[q][rc] = (qrounding_factor * quant_uv_val) >> 7;
cpi->zrun_zbin_boost_uv[q][i] =
ROUND_POWER_OF_TWO(quant_uv_val * zbin_boost[i], 7);
#if CONFIG_ALPHA
invert_quant(cpi->a_quant[q] + rc, cpi->a_quant_shift[q] + rc,
quant_alpha_val);
cpi->a_zbin[q][rc] =
ROUND_POWER_OF_TWO(qzbin_factor * quant_alpha_val, 7);
cpi->a_round[q][rc] = (qrounding_factor * quant_alpha_val) >> 7;
cpi->zrun_zbin_boost_a[q][i] =
ROUND_POWER_OF_TWO(quant_alpha_val * zbin_boost[i], 7);
#endif
}
}
}
void vp9_mb_init_quantizer(VP9_COMP *cpi, MACROBLOCK *x) {
int i;
MACROBLOCKD *xd = &x->e_mbd;
int zbin_extra;
int segment_id = xd->mode_info_context->mbmi.segment_id;
const int qindex = vp9_get_qindex(xd, segment_id, cpi->common.base_qindex);
// Y
zbin_extra = (cpi->common.y_dequant[qindex][1] *
(cpi->zbin_mode_boost + x->act_zbin_adj)) >> 7;
x->plane[0].quant = cpi->y_quant[qindex];
x->plane[0].quant_shift = cpi->y_quant_shift[qindex];
x->plane[0].zbin = cpi->y_zbin[qindex];
x->plane[0].round = cpi->y_round[qindex];
x->plane[0].zrun_zbin_boost = cpi->zrun_zbin_boost_y[qindex];
x->plane[0].zbin_extra = (int16_t)zbin_extra;
x->e_mbd.plane[0].dequant = cpi->common.y_dequant[qindex];
// UV
zbin_extra = (cpi->common.uv_dequant[qindex][1] *
(cpi->zbin_mode_boost + x->act_zbin_adj)) >> 7;
for (i = 1; i < 3; i++) {
x->plane[i].quant = cpi->uv_quant[qindex];
x->plane[i].quant_shift = cpi->uv_quant_shift[qindex];
x->plane[i].zbin = cpi->uv_zbin[qindex];
x->plane[i].round = cpi->uv_round[qindex];
x->plane[i].zrun_zbin_boost = cpi->zrun_zbin_boost_uv[qindex];
x->plane[i].zbin_extra = (int16_t)zbin_extra;
x->e_mbd.plane[i].dequant = cpi->common.uv_dequant[qindex];
}
#if CONFIG_ALPHA
x->plane[3].quant = cpi->a_quant[qindex];
x->plane[3].quant_shift = cpi->a_quant_shift[qindex];
x->plane[3].zbin = cpi->a_zbin[qindex];
x->plane[3].round = cpi->a_round[qindex];
x->plane[3].zrun_zbin_boost = cpi->zrun_zbin_boost_a[qindex];
x->plane[3].zbin_extra = (int16_t)zbin_extra;
x->e_mbd.plane[3].dequant = cpi->common.a_dequant[qindex];
#endif
x->skip_block = vp9_segfeature_active(xd, segment_id, SEG_LVL_SKIP);
/* save this macroblock QIndex for vp9_update_zbin_extra() */
x->e_mbd.q_index = qindex;
}
void vp9_update_zbin_extra(VP9_COMP *cpi, MACROBLOCK *x) {
const int qindex = x->e_mbd.q_index;
const int y_zbin_extra = (cpi->common.y_dequant[qindex][1] *
(cpi->zbin_mode_boost + x->act_zbin_adj)) >> 7;
const int uv_zbin_extra = (cpi->common.uv_dequant[qindex][1] *
(cpi->zbin_mode_boost + x->act_zbin_adj)) >> 7;
x->plane[0].zbin_extra = (int16_t)y_zbin_extra;
x->plane[1].zbin_extra = (int16_t)uv_zbin_extra;
x->plane[2].zbin_extra = (int16_t)uv_zbin_extra;
}
void vp9_frame_init_quantizer(VP9_COMP *cpi) {
// Clear Zbin mode boost for default case
cpi->zbin_mode_boost = 0;
// MB level quantizer setup
vp9_mb_init_quantizer(cpi, &cpi->mb);
}
void vp9_set_quantizer(struct VP9_COMP *cpi, int Q) {
VP9_COMMON *cm = &cpi->common;
cm->base_qindex = Q;
// if any of the delta_q values are changing update flag will
// have to be set.
cm->y_dc_delta_q = 0;
cm->uv_dc_delta_q = 0;
cm->uv_ac_delta_q = 0;
// quantizer has to be reinitialized if any delta_q changes.
// As there are not any here for now this is inactive code.
// if(update)
// vp9_init_quantizer(cpi);
}
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