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aom/av1/encoder/pvq_encoder.c

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/*
* Copyright (c) 2001-2016, 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.
*/
/* clang-format off */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "aom_dsp/entcode.h"
#include "aom_dsp/entenc.h"
#include "av1/common/blockd.h"
#include "av1/common/odintrin.h"
#include "av1/common/partition.h"
#include "av1/common/pvq_state.h"
#include "av1/encoder/encodemb.h"
#include "av1/encoder/pvq_encoder.h"
#include "aom_ports/system_state.h"
/*Shift to ensure that the upper bound (i.e. for the max blocksize) of the
dot-product of the 1st band of chroma with the luma ref doesn't overflow.*/
#define OD_CFL_FLIP_SHIFT (OD_LIMIT_BSIZE_MAX + 0)
void aom_write_symbol_pvq(aom_writer *w, int symb, aom_cdf_prob *cdf,
int nsymbs) {
if (cdf[0] == 0)
aom_cdf_init_q15_1D(cdf, nsymbs, CDF_SIZE(nsymbs));
aom_write_symbol(w, symb, cdf, nsymbs);
}
static void aom_encode_pvq_codeword(aom_writer *w, od_pvq_codeword_ctx *adapt,
const od_coeff *in, int n, int k) {
int i;
aom_encode_band_pvq_splits(w, adapt, in, n, k, 0);
for (i = 0; i < n; i++) if (in[i]) aom_write_bit(w, in[i] < 0);
}
/* Computes 1/sqrt(i) using a table for small values. */
static double od_rsqrt_table(int i) {
static double table[16] = {
1.000000, 0.707107, 0.577350, 0.500000,
0.447214, 0.408248, 0.377964, 0.353553,
0.333333, 0.316228, 0.301511, 0.288675,
0.277350, 0.267261, 0.258199, 0.250000};
if (i <= 16) return table[i-1];
else return 1./sqrt(i);
}
/*Computes 1/sqrt(start+2*i+1) using a lookup table containing the results
where 0 <= i < table_size.*/
static double od_custom_rsqrt_dynamic_table(const double* table,
const int table_size, const double start, const int i) {
if (i < table_size) return table[i];
else return od_rsqrt_table((int)(start + 2*i + 1));
}
/*Fills tables used in od_custom_rsqrt_dynamic_table for a given start.*/
static void od_fill_dynamic_rsqrt_table(double *table, const int table_size,
const double start) {
int i;
for (i = 0; i < table_size; i++)
table[i] = od_rsqrt_table((int)(start + 2*i + 1));
}
/** Find the codepoint on the given PSphere closest to the desired
* vector. Double-precision PVQ search just to make sure our tests
* aren't limited by numerical accuracy.
*
* @param [in] xcoeff input vector to quantize (x in the math doc)
* @param [in] n number of dimensions
* @param [in] k number of pulses
* @param [out] ypulse optimal codevector found (y in the math doc)
* @param [out] g2 multiplier for the distortion (typically squared
* gain units)
* @param [in] pvq_norm_lambda enc->pvq_norm_lambda for quantized RDO
* @param [in] prev_k number of pulses already in ypulse that we should
* reuse for the search (or 0 for a new search)
* @return cosine distance between x and y (between 0 and 1)
*/
double pvq_search_rdo_double_c(const od_val16 *xcoeff, int n, int k,
od_coeff *ypulse, double g2, double pvq_norm_lambda, int prev_k) {
int i, j;
double xy;
double yy;
/* TODO - This blows our 8kB stack space budget and should be fixed when
converting PVQ to fixed point. */
double x[MAXN];
double xx;
double lambda;
double norm_1;
int rdo_pulses;
double delta_rate;
xx = xy = yy = 0;
for (j = 0; j < n; j++) {
x[j] = fabs((float)xcoeff[j]);
xx += x[j]*x[j];
}
norm_1 = 1./sqrt(1e-30 + xx);
lambda = pvq_norm_lambda/(1e-30 + g2);
i = 0;
if (prev_k > 0 && prev_k <= k) {
/* We reuse pulses from a previous search so we don't have to search them
again. */
for (j = 0; j < n; j++) {
ypulse[j] = abs(ypulse[j]);
xy += x[j]*ypulse[j];
yy += ypulse[j]*ypulse[j];
i += ypulse[j];
}
}
else if (k > 2) {
double l1_norm;
double l1_inv;
l1_norm = 0;
for (j = 0; j < n; j++) l1_norm += x[j];
l1_inv = 1./OD_MAXF(l1_norm, 1e-100);
for (j = 0; j < n; j++) {
double tmp;
tmp = k*x[j]*l1_inv;
ypulse[j] = OD_MAXI(0, (int)floor(tmp));
xy += x[j]*ypulse[j];
yy += ypulse[j]*ypulse[j];
i += ypulse[j];
}
}
else OD_CLEAR(ypulse, n);
/* Only use RDO on the last few pulses. This not only saves CPU, but using
RDO on all pulses actually makes the results worse for reasons I don't
fully understand. */
rdo_pulses = 1 + k/4;
/* Rough assumption for now, the last position costs about 3 bits more than
the first. */
delta_rate = 3./n;
/* Search one pulse at a time */
for (; i < k - rdo_pulses; i++) {
int pos;
double best_xy;
double best_yy;
pos = 0;
best_xy = -10;
best_yy = 1;
for (j = 0; j < n; j++) {
double tmp_xy;
double tmp_yy;
tmp_xy = xy + x[j];
tmp_yy = yy + 2*ypulse[j] + 1;
tmp_xy *= tmp_xy;
if (j == 0 || tmp_xy*best_yy > best_xy*tmp_yy) {
best_xy = tmp_xy;
best_yy = tmp_yy;
pos = j;
}
}
xy = xy + x[pos];
yy = yy + 2*ypulse[pos] + 1;
ypulse[pos]++;
}
/* Search last pulses with RDO. Distortion is D = (x-y)^2 = x^2 - 2*x*y + y^2
and since x^2 and y^2 are constant, we just maximize x*y, plus a
lambda*rate term. Note that since x and y aren't normalized here,
we need to divide by sqrt(x^2)*sqrt(y^2). */
for (; i < k; i++) {
double rsqrt_table[4];
int rsqrt_table_size = 4;
int pos;
double best_cost;
pos = 0;
best_cost = -1e5;
/*Fill the small rsqrt lookup table with inputs relative to yy.
Specifically, the table of n values is filled with
rsqrt(yy + 1), rsqrt(yy + 2 + 1) .. rsqrt(yy + 2*(n-1) + 1).*/
od_fill_dynamic_rsqrt_table(rsqrt_table, rsqrt_table_size, yy);
for (j = 0; j < n; j++) {
double tmp_xy;
double tmp_yy;
tmp_xy = xy + x[j];
/*Calculate rsqrt(yy + 2*ypulse[j] + 1) using an optimized method.*/
tmp_yy = od_custom_rsqrt_dynamic_table(rsqrt_table, rsqrt_table_size,
yy, ypulse[j]);
tmp_xy = 2*tmp_xy*norm_1*tmp_yy - lambda*j*delta_rate;
if (j == 0 || tmp_xy > best_cost) {
best_cost = tmp_xy;
pos = j;
}
}
xy = xy + x[pos];
yy = yy + 2*ypulse[pos] + 1;
ypulse[pos]++;
}
for (i = 0; i < n; i++) {
if (xcoeff[i] < 0) ypulse[i] = -ypulse[i];
}
return xy/(1e-100 + sqrt(xx*yy));
}
/** Encodes the gain so that the return value increases with the
* distance |x-ref|, so that we can encode a zero when x=ref. The
* value x=0 is not covered because it is only allowed in the noref
* case.
*
* @param [in] x quantized gain to encode
* @param [in] ref quantized gain of the reference
* @return interleave-encoded quantized gain value
*/
static int neg_interleave(int x, int ref) {
if (x < ref) return -2*(x - ref) - 1;
else if (x < 2*ref) return 2*(x - ref);
else return x-1;
}
int od_vector_is_null(const od_coeff *x, int len) {
int i;
for (i = 0; i < len; i++) if (x[i]) return 0;
return 1;
}
static double od_pvq_rate(int qg, int icgr, int theta, int ts,
const od_adapt_ctx *adapt, const od_coeff *y0, int k, int n, int speed) {
double rate;
if (k == 0) rate = 0;
else if (speed > 0) {
int i;
int sum;
double f;
/* Compute "center of mass" of the pulse vector. */
sum = 0;
for (i = 0; i < n - (theta != -1); i++) sum += i*abs(y0[i]);
f = sum/(double)(k*n);
/* Estimates the number of bits it will cost to encode K pulses in
N dimensions based on hand-tuned fit for bitrate vs K, N and
"center of mass". */
rate = (1 + .4*f)*n*OD_LOG2(1 + OD_MAXF(0, log(n*2*(1*f + .025))*k/n)) + 3;
}
else {
aom_writer w;
od_pvq_codeword_ctx cd;
int tell;
#if !CONFIG_ANS
od_ec_enc_init(&w.ec, 1000);
#else
# error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
OD_COPY(&cd, &adapt->pvq.pvq_codeword_ctx, 1);
#if !CONFIG_ANS
tell = od_ec_enc_tell_frac(&w.ec);
#else
# error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
aom_encode_pvq_codeword(&w, &cd, y0, n - (theta != -1), k);
#if !CONFIG_ANS
rate = (od_ec_enc_tell_frac(&w.ec)-tell)/8.;
od_ec_enc_clear(&w.ec);
#else
# error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
}
if (qg > 0 && theta >= 0) {
/* Approximate cost of entropy-coding theta */
rate += .9*OD_LOG2(ts);
if (qg == icgr) rate -= .5;
}
return rate;
}
#define MAX_PVQ_ITEMS (20)
/* This stores the information about a PVQ search candidate, so we can sort
based on K. */
typedef struct {
int gain;
int k;
od_val32 qtheta;
int theta;
int ts;
od_val32 qcg;
} pvq_search_item;
int items_compare(pvq_search_item *a, pvq_search_item *b) {
/* Break ties in K with gain to ensure a stable sort.
Otherwise, the order depends on qsort implementation. */
return a->k == b->k ? a->gain - b->gain : a->k - b->k;
}
/** Perform PVQ quantization with prediction, trying several
* possible gains and angles. See draft-valin-videocodec-pvq and
* http://jmvalin.ca/slides/pvq.pdf for more details.
*
* @param [out] out coefficients after quantization
* @param [in] x0 coefficients before quantization
* @param [in] r0 reference, aka predicted coefficients
* @param [in] n number of dimensions
* @param [in] q0 quantization step size
* @param [out] y pulse vector (i.e. selected PVQ codevector)
* @param [out] itheta angle between input and reference (-1 if noref)
* @param [out] vk total number of pulses
* @param [in] beta per-band activity masking beta param
* @param [out] skip_diff distortion cost of skipping this block
* (accumulated)
* @param [in] is_keyframe whether we're encoding a keyframe
* @param [in] pli plane index
* @param [in] adapt probability adaptation context
* @param [in] qm QM with magnitude compensation
* @param [in] qm_inv Inverse of QM with magnitude compensation
* @param [in] pvq_norm_lambda enc->pvq_norm_lambda for quantized RDO
* @param [in] speed Make search faster by making approximations
* @return gain index of the quatized gain
*/
static int pvq_theta(od_coeff *out, const od_coeff *x0, const od_coeff *r0,
int n, int q0, od_coeff *y, int *itheta, int *vk,
od_val16 beta, double *skip_diff, int is_keyframe, int pli,
const od_adapt_ctx *adapt, const int16_t *qm, const int16_t *qm_inv,
double pvq_norm_lambda, int speed) {
od_val32 g;
od_val32 gr;
od_coeff y_tmp[MAXN + 3];
int i;
/* Number of pulses. */
int k;
/* Companded gain of x and reference, normalized to q. */
od_val32 cg;
od_val32 cgr;
int icgr;
int qg;
/* Best RDO cost (D + lamdba*R) so far. */
double best_cost;
double dist0;
/* Distortion (D) that corresponds to the best RDO cost. */
double best_dist;
double dist;
/* Sign of Householder reflection. */
int s;
/* Dimension on which Householder reflects. */
int m;
od_val32 theta;
double corr;
int best_k;
od_val32 best_qtheta;
od_val32 gain_offset;
int noref;
double skip_dist;
int cfl_enabled;
int skip;
double gain_weight;
od_val16 x16[MAXN];
od_val16 r16[MAXN];
int xshift;
int rshift;
/* Give more weight to gain error when calculating the total distortion. */
gain_weight = 1.0;
OD_ASSERT(n > 1);
corr = 0;
#if !defined(OD_FLOAT_PVQ)
/* Shift needed to make x fit in 16 bits even after rotation.
This shift value is not normative (it can be changed without breaking
the bitstream) */
xshift = OD_MAXI(0, od_vector_log_mag(x0, n) - 15);
/* Shift needed to make the reference fit in 15 bits, so that the Householder
vector can fit in 16 bits.
This shift value *is* normative, and has to match the decoder. */
rshift = OD_MAXI(0, od_vector_log_mag(r0, n) - 14);
#else
xshift = 0;
rshift = 0;
#endif
for (i = 0; i < n; i++) {
#if defined(OD_FLOAT_PVQ)
/*This is slightly different from the original float PVQ code,
where the qm was applied in the accumulation in od_pvq_compute_gain and
the vectors were od_coeffs, not od_val16 (i.e. double).*/
x16[i] = x0[i]*(double)qm[i]*OD_QM_SCALE_1;
r16[i] = r0[i]*(double)qm[i]*OD_QM_SCALE_1;
#else
x16[i] = OD_SHR_ROUND(x0[i]*qm[i], OD_QM_SHIFT + xshift);
r16[i] = OD_SHR_ROUND(r0[i]*qm[i], OD_QM_SHIFT + rshift);
#endif
corr += OD_MULT16_16(x16[i], r16[i]);
}
cfl_enabled = is_keyframe && pli != 0 && !OD_DISABLE_CFL;
cg = od_pvq_compute_gain(x16, n, q0, &g, beta, xshift);
cgr = od_pvq_compute_gain(r16, n, q0, &gr, beta, rshift);
if (cfl_enabled) cgr = OD_CGAIN_SCALE;
/* gain_offset is meant to make sure one of the quantized gains has
exactly the same gain as the reference. */
#if defined(OD_FLOAT_PVQ)
icgr = (int)floor(.5 + cgr);
#else
icgr = OD_SHR_ROUND(cgr, OD_CGAIN_SHIFT);
#endif
gain_offset = cgr - OD_SHL(icgr, OD_CGAIN_SHIFT);
/* Start search with null case: gain=0, no pulse. */
qg = 0;
dist = gain_weight*cg*cg*OD_CGAIN_SCALE_2;
best_dist = dist;
best_cost = dist + pvq_norm_lambda*od_pvq_rate(0, 0, -1, 0, adapt, NULL, 0,
n, speed);
noref = 1;
best_k = 0;
*itheta = -1;
OD_CLEAR(y, n);
best_qtheta = 0;
m = 0;
s = 1;
corr = corr/(1e-100 + g*(double)gr/OD_SHL(1, xshift + rshift));
corr = OD_MAXF(OD_MINF(corr, 1.), -1.);
if (is_keyframe) skip_dist = gain_weight*cg*cg*OD_CGAIN_SCALE_2;
else {
skip_dist = gain_weight*(cg - cgr)*(cg - cgr)
+ cgr*(double)cg*(2 - 2*corr);
skip_dist *= OD_CGAIN_SCALE_2;
}
if (!is_keyframe) {
/* noref, gain=0 isn't allowed, but skip is allowed. */
od_val32 scgr;
scgr = OD_MAXF(0,gain_offset);
if (icgr == 0) {
best_dist = gain_weight*(cg - scgr)*(cg - scgr)
+ scgr*(double)cg*(2 - 2*corr);
best_dist *= OD_CGAIN_SCALE_2;
}
best_cost = best_dist + pvq_norm_lambda*od_pvq_rate(0, icgr, 0, 0, adapt,
NULL, 0, n, speed);
best_qtheta = 0;
*itheta = 0;
noref = 0;
}
dist0 = best_dist;
if (n <= OD_MAX_PVQ_SIZE && !od_vector_is_null(r0, n) && corr > 0) {
od_val16 xr[MAXN];
int gain_bound;
int prev_k;
pvq_search_item items[MAX_PVQ_ITEMS];
int idx;
int nitems;
double cos_dist;
idx = 0;
gain_bound = OD_SHR(cg - gain_offset, OD_CGAIN_SHIFT);
/* Perform theta search only if prediction is useful. */
theta = OD_ROUND32(OD_THETA_SCALE*acos(corr));
m = od_compute_householder(r16, n, gr, &s, rshift);
od_apply_householder(xr, x16, r16, n);
prev_k = 0;
for (i = m; i < n - 1; i++) xr[i] = xr[i + 1];
/* Compute all candidate PVQ searches within a reasonable range of gain
and theta. */
for (i = OD_MAXI(1, gain_bound - 1); i <= gain_bound + 1; i++) {
int j;
od_val32 qcg;
int ts;
int theta_lower;
int theta_upper;
/* Quantized companded gain */
qcg = OD_SHL(i, OD_CGAIN_SHIFT) + gain_offset;
/* Set angular resolution (in ra) to match the encoded gain */
ts = od_pvq_compute_max_theta(qcg, beta);
theta_lower = OD_MAXI(0, (int)floor(.5 +
theta*OD_THETA_SCALE_1*2/M_PI*ts) - 2);
theta_upper = OD_MINI(ts - 1, (int)ceil(theta*OD_THETA_SCALE_1*2/M_PI*ts));
/* Include the angles within a reasonable range. */
for (j = theta_lower; j <= theta_upper; j++) {
od_val32 qtheta;
qtheta = od_pvq_compute_theta(j, ts);
k = od_pvq_compute_k(qcg, j, 0, n, beta);
items[idx].gain = i;
items[idx].theta = j;
items[idx].k = k;
items[idx].qcg = qcg;
items[idx].qtheta = qtheta;
items[idx].ts = ts;
idx++;
OD_ASSERT(idx < MAX_PVQ_ITEMS);
}
}
nitems = idx;
cos_dist = 0;
/* Sort PVQ search candidates in ascending order of pulses K so that
we can reuse all the previously searched pulses across searches. */
qsort(items, nitems, sizeof(items[0]),
(int (*)(const void *, const void *))items_compare);
/* Search for the best gain/theta in order. */
for (idx = 0; idx < nitems; idx++) {
int j;
od_val32 qcg;
int ts;
double cost;
double dist_theta;
double sin_prod;
od_val32 qtheta;
/* Quantized companded gain */
qcg = items[idx].qcg;
i = items[idx].gain;
j = items[idx].theta;
/* Set angular resolution (in ra) to match the encoded gain */
ts = items[idx].ts;
/* Search for the best angle within a reasonable range. */
qtheta = items[idx].qtheta;
k = items[idx].k;
/* Compute the minimal possible distortion by not taking the PVQ
cos_dist into account. */
dist_theta = 2 - 2.*od_pvq_cos(theta - qtheta)*OD_TRIG_SCALE_1;
dist = gain_weight*(qcg - cg)*(qcg - cg) + qcg*(double)cg*dist_theta;
dist *= OD_CGAIN_SCALE_2;
/* If we have no hope of beating skip (including a 1-bit worst-case
penalty), stop now. */
if (dist > dist0 + 1.0*pvq_norm_lambda && k != 0) continue;
sin_prod = od_pvq_sin(theta)*OD_TRIG_SCALE_1*od_pvq_sin(qtheta)*
OD_TRIG_SCALE_1;
/* PVQ search, using a gain of qcg*cg*sin(theta)*sin(qtheta) since
that's the factor by which cos_dist is multiplied to get the
distortion metric. */
if (k == 0) {
cos_dist = 0;
OD_CLEAR(y_tmp, n-1);
}
else if (k != prev_k) {
cos_dist = pvq_search_rdo_double(xr, n - 1, k, y_tmp,
qcg*(double)cg*sin_prod*OD_CGAIN_SCALE_2, pvq_norm_lambda, prev_k);
}
prev_k = k;
/* See Jmspeex' Journal of Dubious Theoretical Results. */
dist_theta = 2 - 2.*od_pvq_cos(theta - qtheta)*OD_TRIG_SCALE_1
+ sin_prod*(2 - 2*cos_dist);
dist = gain_weight*(qcg - cg)*(qcg - cg) + qcg*(double)cg*dist_theta;
dist *= OD_CGAIN_SCALE_2;
/* Do approximate RDO. */
cost = dist + pvq_norm_lambda*od_pvq_rate(i, icgr, j, ts, adapt, y_tmp,
k, n, speed);
if (cost < best_cost) {
best_cost = cost;
best_dist = dist;
qg = i;
best_k = k;
best_qtheta = qtheta;
*itheta = j;
noref = 0;
OD_COPY(y, y_tmp, n - 1);
}
}
}
/* Don't bother with no-reference version if there's a reasonable
correlation. */
if (n <= OD_MAX_PVQ_SIZE && (corr < .5
|| cg < (od_val32)(OD_SHL(2, OD_CGAIN_SHIFT)))) {
int gain_bound;
int prev_k;
gain_bound = OD_SHR(cg, OD_CGAIN_SHIFT);
prev_k = 0;
/* Search for the best gain (haven't determined reasonable range yet). */
for (i = OD_MAXI(1, gain_bound); i <= gain_bound + 1; i++) {
double cos_dist;
double cost;
od_val32 qcg;
qcg = OD_SHL(i, OD_CGAIN_SHIFT);
k = od_pvq_compute_k(qcg, -1, 1, n, beta);
/* Compute the minimal possible distortion by not taking the PVQ
cos_dist into account. */
dist = gain_weight*(qcg - cg)*(qcg - cg);
dist *= OD_CGAIN_SCALE_2;
if (dist > dist0 && k != 0) continue;
cos_dist = pvq_search_rdo_double(x16, n, k, y_tmp,
qcg*(double)cg*OD_CGAIN_SCALE_2, pvq_norm_lambda, prev_k);
prev_k = k;
/* See Jmspeex' Journal of Dubious Theoretical Results. */
dist = gain_weight*(qcg - cg)*(qcg - cg)
+ qcg*(double)cg*(2 - 2*cos_dist);
dist *= OD_CGAIN_SCALE_2;
/* Do approximate RDO. */
cost = dist + pvq_norm_lambda*od_pvq_rate(i, 0, -1, 0, adapt, y_tmp, k,
n, speed);
if (cost <= best_cost) {
best_cost = cost;
best_dist = dist;
qg = i;
noref = 1;
best_k = k;
*itheta = -1;
OD_COPY(y, y_tmp, n);
}
}
}
k = best_k;
theta = best_qtheta;
skip = 0;
if (noref) {
if (qg == 0) skip = OD_PVQ_SKIP_ZERO;
}
else {
if (!is_keyframe && qg == 0) {
skip = (icgr ? OD_PVQ_SKIP_ZERO : OD_PVQ_SKIP_COPY);
}
if (qg == icgr && *itheta == 0 && !cfl_enabled) skip = OD_PVQ_SKIP_COPY;
}
/* Synthesize like the decoder would. */
if (skip) {
if (skip == OD_PVQ_SKIP_COPY) OD_COPY(out, r0, n);
else OD_CLEAR(out, n);
}
else {
if (noref) gain_offset = 0;
g = od_gain_expand(OD_SHL(qg, OD_CGAIN_SHIFT) + gain_offset, q0, beta);
od_pvq_synthesis_partial(out, y, r16, n, noref, g, theta, m, s,
qm_inv);
}
*vk = k;
*skip_diff += skip_dist - best_dist;
/* Encode gain differently depending on whether we use prediction or not.
Special encoding on inter frames where qg=0 is allowed for noref=0
but not noref=1.*/
if (is_keyframe) return noref ? qg : neg_interleave(qg, icgr);
else return noref ? qg - 1 : neg_interleave(qg + 1, icgr + 1);
}
/** Encodes a single vector of integers (eg, a partition within a
* coefficient block) using PVQ
*
* @param [in,out] w multi-symbol entropy encoder
* @param [in] qg quantized gain
* @param [in] theta quantized post-prediction theta
* @param [in] in coefficient vector to code
* @param [in] n number of coefficients in partition
* @param [in] k number of pulses in partition
* @param [in,out] model entropy encoder state
* @param [in,out] adapt adaptation context
* @param [in,out] exg ExQ16 expectation of gain value
* @param [in,out] ext ExQ16 expectation of theta value
* @param [in] cdf_ctx selects which cdf context to use
* @param [in] is_keyframe whether we're encoding a keyframe
* @param [in] code_skip whether the "skip rest" flag is allowed
* @param [in] skip_rest when set, we skip all higher bands
* @param [in] encode_flip whether we need to encode the CfL flip flag now
* @param [in] flip value of the CfL flip flag
*/
void pvq_encode_partition(aom_writer *w,
int qg,
int theta,
const od_coeff *in,
int n,
int k,
generic_encoder model[3],
od_adapt_ctx *adapt,
int *exg,
int *ext,
int cdf_ctx,
int is_keyframe,
int code_skip,
int skip_rest,
int encode_flip,
int flip) {
int noref;
int id;
noref = (theta == -1);
id = (qg > 0) + 2*OD_MINI(theta + 1,3) + 8*code_skip*skip_rest;
if (is_keyframe) {
OD_ASSERT(id != 8);
if (id >= 8) id--;
}
else {
OD_ASSERT(id != 10);
if (id >= 10) id--;
}
/* Jointly code gain, theta and noref for small values. Then we handle
larger gain and theta values. For noref, theta = -1. */
aom_write_symbol_pvq(w, id, &adapt->pvq.pvq_gaintheta_cdf[cdf_ctx][0],
8 + 7*code_skip);
if (encode_flip) {
/* We could eventually do some smarter entropy coding here, but it would
have to be good enough to overcome the overhead of the entropy coder.
An early attempt using a "toogle" flag with simple adaptation wasn't
worth the trouble. */
aom_write_bit(w, flip);
}
if (qg > 0) {
int tmp;
tmp = *exg;
generic_encode(w, &model[!noref], qg - 1, &tmp, 2);
OD_IIR_DIADIC(*exg, qg << 16, 2);
}
if (theta > 1) {
int tmp;
tmp = *ext;
generic_encode(w, &model[2], theta - 2, &tmp, 2);
OD_IIR_DIADIC(*ext, theta << 16, 2);
}
aom_encode_pvq_codeword(w, &adapt->pvq.pvq_codeword_ctx, in,
n - (theta != -1), k);
}
/** Quantizes a scalar with rate-distortion optimization (RDO)
* @param [in] x unquantized value
* @param [in] q quantization step size
* @param [in] delta0 rate increase for encoding a 1 instead of a 0
* @param [in] pvq_norm_lambda enc->pvq_norm_lambda for quantized RDO
* @retval quantized value
*/
int od_rdo_quant(od_coeff x, int q, double delta0, double pvq_norm_lambda) {
int n;
/* Optimal quantization threshold is 1/2 + lambda*delta_rate/2. See
Jmspeex' Journal of Dubious Theoretical Results for details. */
n = OD_DIV_R0(abs(x), q);
if ((double)abs(x)/q < (double)n/2 + pvq_norm_lambda*delta0/(2*n)) {
return 0;
}
else {
return OD_DIV_R0(x, q);
}
}
/** Encode a coefficient block (excepting DC) using PVQ
*
* @param [in,out] enc daala encoder context
* @param [in] ref 'reference' (prediction) vector
* @param [in] in coefficient block to quantize and encode
* @param [out] out quantized coefficient block
* @param [in] q0 scale/quantizer
* @param [in] pli plane index
* @param [in] bs log of the block size minus two
* @param [in] beta per-band activity masking beta param
* @param [in] is_keyframe whether we're encoding a keyframe
* @param [in] qm QM with magnitude compensation
* @param [in] qm_inv Inverse of QM with magnitude compensation
* @param [in] speed Make search faster by making approximations
* @param [in] pvq_info If null, conisdered as RDO search mode
* @return Returns block skip info indicating whether DC/AC are coded.
* bit0: DC is coded, bit1: AC is coded (1 means coded)
*
*/
PVQ_SKIP_TYPE od_pvq_encode(daala_enc_ctx *enc,
od_coeff *ref,
const od_coeff *in,
od_coeff *out,
int q_dc,
int q_ac,
int pli,
int bs,
const od_val16 *beta,
int is_keyframe,
const int16_t *qm,
const int16_t *qm_inv,
int speed,
PVQ_INFO *pvq_info){
int theta[PVQ_MAX_PARTITIONS];
int qg[PVQ_MAX_PARTITIONS];
int k[PVQ_MAX_PARTITIONS];
od_coeff y[OD_TXSIZE_MAX*OD_TXSIZE_MAX];
int *exg;
int *ext;
int nb_bands;
int i;
const int *off;
int size[PVQ_MAX_PARTITIONS];
generic_encoder *model;
double skip_diff;
int tell;
uint16_t *skip_cdf;
od_rollback_buffer buf;
int dc_quant;
int flip;
int cfl_encoded;
int skip_rest;
int skip_dir;
int skip_theta_value;
const unsigned char *pvq_qm;
double dc_rate;
int use_masking;
PVQ_SKIP_TYPE ac_dc_coded;
aom_clear_system_state();
use_masking = enc->use_activity_masking;
if (use_masking)
pvq_qm = &enc->state.pvq_qm_q4[pli][0];
else
pvq_qm = 0;
exg = &enc->state.adapt->pvq.pvq_exg[pli][bs][0];
ext = enc->state.adapt->pvq.pvq_ext + bs*PVQ_MAX_PARTITIONS;
skip_cdf = enc->state.adapt->skip_cdf[2*bs + (pli != 0)];
model = enc->state.adapt->pvq.pvq_param_model;
nb_bands = OD_BAND_OFFSETS[bs][0];
off = &OD_BAND_OFFSETS[bs][1];
if (use_masking)
dc_quant = OD_MAXI(1, q_dc * pvq_qm[od_qm_get_index(bs, 0)] >> 4);
else
dc_quant = OD_MAXI(1, q_dc);
tell = 0;
for (i = 0; i < nb_bands; i++) size[i] = off[i+1] - off[i];
skip_diff = 0;
flip = 0;
/*If we are coding a chroma block of a keyframe, we are doing CfL.*/
if (pli != 0 && is_keyframe) {
od_val32 xy;
xy = 0;
/*Compute the dot-product of the first band of chroma with the luma ref.*/
for (i = off[0]; i < off[1]; i++) {
#if defined(OD_FLOAT_PVQ)
xy += ref[i]*(double)qm[i]*OD_QM_SCALE_1*
(double)in[i]*(double)qm[i]*OD_QM_SCALE_1;
#else
od_val32 rq;
od_val32 inq;
rq = ref[i]*qm[i];
inq = in[i]*qm[i];
xy += OD_SHR(rq*(int64_t)inq, OD_SHL(OD_QM_SHIFT + OD_CFL_FLIP_SHIFT,
1));
#endif
}
/*If cos(theta) < 0, then |theta| > pi/2 and we should negate the ref.*/
if (xy < 0) {
flip = 1;
for(i = off[0]; i < off[nb_bands]; i++) ref[i] = -ref[i];
}
}
for (i = 0; i < nb_bands; i++) {
int q;
if (use_masking)
q = OD_MAXI(1, q_ac * pvq_qm[od_qm_get_index(bs, i + 1)] >> 4);
else
q = OD_MAXI(1, q_ac);
qg[i] = pvq_theta(out + off[i], in + off[i], ref + off[i], size[i],
q, y + off[i], &theta[i], &k[i], beta[i], &skip_diff, is_keyframe,
pli, enc->state.adapt, qm + off[i], qm_inv + off[i],
enc->pvq_norm_lambda, speed);
}
od_encode_checkpoint(enc, &buf);
if (is_keyframe) out[0] = 0;
else {
int n;
n = OD_DIV_R0(abs(in[0] - ref[0]), dc_quant);
if (n == 0) {
out[0] = 0;
} else {
int tell2;
od_rollback_buffer dc_buf;
dc_rate = -OD_LOG2((double)(OD_ICDF(skip_cdf[3]) - OD_ICDF(skip_cdf[2]))/
(double)(OD_ICDF(skip_cdf[2]) - OD_ICDF(skip_cdf[1])));
dc_rate += 1;
#if !CONFIG_ANS
tell2 = od_ec_enc_tell_frac(&enc->w.ec);
#else
#error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
od_encode_checkpoint(enc, &dc_buf);
generic_encode(&enc->w, &enc->state.adapt->model_dc[pli],
n - 1, &enc->state.adapt->ex_dc[pli][bs][0], 2);
#if !CONFIG_ANS
tell2 = od_ec_enc_tell_frac(&enc->w.ec) - tell2;
#else
#error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
dc_rate += tell2/8.0;
od_encode_rollback(enc, &dc_buf);
out[0] = od_rdo_quant(in[0] - ref[0], dc_quant, dc_rate,
enc->pvq_norm_lambda);
}
}
#if !CONFIG_ANS
tell = od_ec_enc_tell_frac(&enc->w.ec);
#else
#error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
/* Code as if we're not skipping. */
aom_write_symbol(&enc->w, 2 + (out[0] != 0), skip_cdf, 4);
ac_dc_coded = AC_CODED + (out[0] != 0);
cfl_encoded = 0;
skip_rest = 1;
skip_theta_value = is_keyframe ? -1 : 0;
for (i = 1; i < nb_bands; i++) {
if (theta[i] != skip_theta_value || qg[i]) skip_rest = 0;
}
skip_dir = 0;
if (nb_bands > 1) {
for (i = 0; i < 3; i++) {
int j;
int tmp;
tmp = 1;
// ToDo(yaowu): figure out better stop condition without gcc warning.
for (j = i + 1; j < nb_bands && j < PVQ_MAX_PARTITIONS; j += 3) {
if (theta[j] != skip_theta_value || qg[j]) tmp = 0;
}
skip_dir |= tmp << i;
}
}
if (theta[0] == skip_theta_value && qg[0] == 0 && skip_rest) nb_bands = 0;
/* NOTE: There was no other better place to put this function. */
if (pvq_info)
av1_store_pvq_enc_info(pvq_info, qg, theta, k, y, nb_bands, off, size,
skip_rest, skip_dir, bs);
for (i = 0; i < nb_bands; i++) {
int encode_flip;
/* Encode CFL flip bit just after the first time it's used. */
encode_flip = pli != 0 && is_keyframe && theta[i] != -1 && !cfl_encoded;
if (i == 0 || (!skip_rest && !(skip_dir & (1 << ((i - 1)%3))))) {
pvq_encode_partition(&enc->w, qg[i], theta[i], y + off[i],
size[i], k[i], model, enc->state.adapt, exg + i, ext + i,
(pli != 0)*OD_TXSIZES*PVQ_MAX_PARTITIONS + bs*PVQ_MAX_PARTITIONS + i,
is_keyframe, i == 0 && (i < nb_bands - 1), skip_rest, encode_flip, flip);
}
if (i == 0 && !skip_rest && bs > 0) {
aom_write_symbol(&enc->w, skip_dir,
&enc->state.adapt->pvq.pvq_skip_dir_cdf[(pli != 0) + 2*(bs - 1)][0], 7);
}
if (encode_flip) cfl_encoded = 1;
}
#if !CONFIG_ANS
tell = od_ec_enc_tell_frac(&enc->w.ec) - tell;
#else
#error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
/* Account for the rate of skipping the AC, based on the same DC decision
we made when trying to not skip AC. */
{
double skip_rate;
if (out[0] != 0) {
skip_rate = -OD_LOG2((OD_ICDF(skip_cdf[1]) - OD_ICDF(skip_cdf[0]))/
(double)OD_ICDF(skip_cdf[3]));
}
else {
skip_rate = -OD_LOG2(OD_ICDF(skip_cdf[0])/
(double)OD_ICDF(skip_cdf[3]));
}
tell -= (int)floor(.5+8*skip_rate);
}
if (nb_bands == 0 || skip_diff <= enc->pvq_norm_lambda/8*tell) {
if (is_keyframe) out[0] = 0;
else {
int n;
n = OD_DIV_R0(abs(in[0] - ref[0]), dc_quant);
if (n == 0) {
out[0] = 0;
} else {
int tell2;
od_rollback_buffer dc_buf;
dc_rate = -OD_LOG2((double)(OD_ICDF(skip_cdf[1]) - OD_ICDF(skip_cdf[0]))/
(double)OD_ICDF(skip_cdf[0]));
dc_rate += 1;
#if !CONFIG_ANS
tell2 = od_ec_enc_tell_frac(&enc->w.ec);
#else
#error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
od_encode_checkpoint(enc, &dc_buf);
generic_encode(&enc->w, &enc->state.adapt->model_dc[pli],
n - 1, &enc->state.adapt->ex_dc[pli][bs][0], 2);
#if !CONFIG_ANS
tell2 = od_ec_enc_tell_frac(&enc->w.ec) - tell2;
#else
#error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
dc_rate += tell2/8.0;
od_encode_rollback(enc, &dc_buf);
out[0] = od_rdo_quant(in[0] - ref[0], dc_quant, dc_rate,
enc->pvq_norm_lambda);
}
}
/* We decide to skip, roll back everything as it was before. */
od_encode_rollback(enc, &buf);
aom_write_symbol(&enc->w, out[0] != 0, skip_cdf, 4);
ac_dc_coded = (out[0] != 0);
if (is_keyframe) for (i = 1; i < 1 << (2*bs + 4); i++) out[i] = 0;
else for (i = 1; i < 1 << (2*bs + 4); i++) out[i] = ref[i];
}
if (pvq_info)
pvq_info->ac_dc_coded = ac_dc_coded;
return ac_dc_coded;
}
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