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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 <stdio.h>
#include "aom_dsp/bitreader.h"
#include "av1/common/pvq.h"
#include "pvq_decoder.h"
#define aom_decode_pvq_split(r, adapt, sum, ctx, ACCT_STR_NAME) \
aom_decode_pvq_split_(r, adapt, sum, ctx ACCT_STR_ARG(ACCT_STR_NAME))
static int aom_decode_pvq_split_(aom_reader *r, od_pvq_codeword_ctx *adapt,
int sum, int ctx ACCT_STR_PARAM) {
int shift;
int count;
int msbs;
int fctx;
count = 0;
if (sum == 0) return 0;
shift = OD_MAXI(0, OD_ILOG(sum) - 3);
fctx = 7*ctx + (sum >> shift) - 1;
msbs = aom_read_symbol_pvq(r, adapt->pvq_split_cdf[fctx], (sum >> shift) + 1,
ACCT_STR_NAME);
if (shift) count = aom_read_literal(r, shift, ACCT_STR_NAME);
count += msbs << shift;
if (count > sum) {
count = sum;
#if !CONFIG_ANS
r->ec.error = 1;
#else
# error "CONFIG_PVQ currently requires !CONFIG_ANS."
#endif
}
return count;
}
void aom_decode_band_pvq_splits(aom_reader *r, od_pvq_codeword_ctx *adapt,
od_coeff *y, int n, int k, int level) {
int mid;
int count_right;
if (n == 1) {
y[0] = k;
}
else if (k == 0) {
OD_CLEAR(y, n);
}
else if (k == 1 && n <= 16) {
int cdf_id;
int pos;
cdf_id = od_pvq_k1_ctx(n, level == 0);
OD_CLEAR(y, n);
pos = aom_read_symbol_pvq(r, adapt->pvq_k1_cdf[cdf_id], n, "pvq:k1");
y[pos] = 1;
}
else {
mid = n >> 1;
count_right = aom_decode_pvq_split(r, adapt, k, od_pvq_size_ctx(n),
"pvq:split");
aom_decode_band_pvq_splits(r, adapt, y, mid, k - count_right, level + 1);
aom_decode_band_pvq_splits(r, adapt, y + mid, n - mid, count_right,
level + 1);
}
}
/** Decodes the tail of a Laplace-distributed variable, i.e. it doesn't
* do anything special for the zero case.
*
* @param [dec] range decoder
* @param [decay] decay factor of the distribution, i.e. pdf ~= decay^x
*
* @retval decoded variable x
*/
int aom_laplace_decode_special_(aom_reader *r, unsigned decay ACCT_STR_PARAM) {
int pos;
int shift;
int xs;
int sym;
const uint16_t *cdf;
shift = 0;
/* We don't want a large decay value because that would require too many
symbols. */
while (decay > 235) {
decay = (decay*decay + 128) >> 8;
shift++;
}
decay = OD_MINI(decay, 254);
decay = OD_MAXI(decay, 2);
cdf = EXP_CDF_TABLE[(decay + 1) >> 1];
OD_LOG((OD_LOG_PVQ, OD_LOG_DEBUG, "decay = %d\n", decay));
xs = 0;
do {
sym = OD_MINI(xs, 15);
{
int i;
OD_LOG((OD_LOG_PVQ, OD_LOG_DEBUG, "%d %d %d", xs, shift, sym));
for (i = 0; i < 16; i++) {
OD_LOG_PARTIAL((OD_LOG_PVQ, OD_LOG_DEBUG, "%d ", cdf[i]));
}
OD_LOG_PARTIAL((OD_LOG_PVQ, OD_LOG_DEBUG, "\n"));
}
sym = aom_read_cdf(r, cdf, 16, ACCT_STR_NAME);
xs += sym;
} while (sym >= 15);
if (shift) pos = (xs << shift) + aom_read_literal(r, shift, ACCT_STR_NAME);
else pos = xs;
return pos;
}
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