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ffmpeg/libavcodec/opus_celt.c

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/*
* Copyright (c) 2012 Andrew D'Addesio
* Copyright (c) 2013-2014 Mozilla Corporation
* Copyright (c) 2016 Rostislav Pehlivanov <atomnuker@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Opus CELT decoder
*/
#include "opus_celt.h"
#include "opustab.h"
#include "opus_pvq.h"
static void celt_decode_coarse_energy(CeltFrame *f, OpusRangeCoder *rc)
{
int i, j;
float prev[2] = {0};
float alpha, beta;
const uint8_t *model;
/* use the 2D z-transform to apply prediction in both */
/* the time domain (alpha) and the frequency domain (beta) */
if (opus_rc_tell(rc)+3 <= f->framebits && ff_opus_rc_dec_log(rc, 3)) {
/* intra frame */
alpha = 0;
beta = 1.0f - 4915.0f/32768.0f;
model = ff_celt_coarse_energy_dist[f->size][1];
} else {
alpha = ff_celt_alpha_coef[f->size];
beta = 1.0f - ff_celt_beta_coef[f->size];
model = ff_celt_coarse_energy_dist[f->size][0];
}
for (i = 0; i < CELT_MAX_BANDS; i++) {
for (j = 0; j < f->channels; j++) {
CeltBlock *block = &f->block[j];
float value;
int available;
if (i < f->start_band || i >= f->end_band) {
block->energy[i] = 0.0;
continue;
}
available = f->framebits - opus_rc_tell(rc);
if (available >= 15) {
/* decode using a Laplace distribution */
int k = FFMIN(i, 20) << 1;
value = ff_opus_rc_dec_laplace(rc, model[k] << 7, model[k+1] << 6);
} else if (available >= 2) {
int x = ff_opus_rc_dec_cdf(rc, ff_celt_model_energy_small);
value = (x>>1) ^ -(x&1);
} else if (available >= 1) {
value = -(float)ff_opus_rc_dec_log(rc, 1);
} else value = -1;
block->energy[i] = FFMAX(-9.0f, block->energy[i]) * alpha + prev[j] + value;
prev[j] += beta * value;
}
}
}
static void celt_decode_fine_energy(CeltFrame *f, OpusRangeCoder *rc)
{
int i;
for (i = f->start_band; i < f->end_band; i++) {
int j;
if (!f->fine_bits[i])
continue;
for (j = 0; j < f->channels; j++) {
CeltBlock *block = &f->block[j];
int q2;
float offset;
q2 = ff_opus_rc_get_raw(rc, f->fine_bits[i]);
offset = (q2 + 0.5f) * (1 << (14 - f->fine_bits[i])) / 16384.0f - 0.5f;
block->energy[i] += offset;
}
}
}
static void celt_decode_final_energy(CeltFrame *f, OpusRangeCoder *rc)
{
int priority, i, j;
int bits_left = f->framebits - opus_rc_tell(rc);
for (priority = 0; priority < 2; priority++) {
for (i = f->start_band; i < f->end_band && bits_left >= f->channels; i++) {
if (f->fine_priority[i] != priority || f->fine_bits[i] >= CELT_MAX_FINE_BITS)
continue;
for (j = 0; j < f->channels; j++) {
int q2;
float offset;
q2 = ff_opus_rc_get_raw(rc, 1);
offset = (q2 - 0.5f) * (1 << (14 - f->fine_bits[i] - 1)) / 16384.0f;
f->block[j].energy[i] += offset;
bits_left--;
}
}
}
}
static void celt_decode_tf_changes(CeltFrame *f, OpusRangeCoder *rc)
{
int i, diff = 0, tf_select = 0, tf_changed = 0, tf_select_bit;
int consumed, bits = f->transient ? 2 : 4;
consumed = opus_rc_tell(rc);
tf_select_bit = (f->size != 0 && consumed+bits+1 <= f->framebits);
for (i = f->start_band; i < f->end_band; i++) {
if (consumed+bits+tf_select_bit <= f->framebits) {
diff ^= ff_opus_rc_dec_log(rc, bits);
consumed = opus_rc_tell(rc);
tf_changed |= diff;
}
f->tf_change[i] = diff;
bits = f->transient ? 4 : 5;
}
if (tf_select_bit && ff_celt_tf_select[f->size][f->transient][0][tf_changed] !=
ff_celt_tf_select[f->size][f->transient][1][tf_changed])
tf_select = ff_opus_rc_dec_log(rc, 1);
for (i = f->start_band; i < f->end_band; i++) {
f->tf_change[i] = ff_celt_tf_select[f->size][f->transient][tf_select][f->tf_change[i]];
}
}
static void celt_decode_allocation(CeltFrame *f, OpusRangeCoder *rc)
{
// approx. maximum bit allocation for each band before boost/trim
int cap[CELT_MAX_BANDS];
int boost[CELT_MAX_BANDS];
int threshold[CELT_MAX_BANDS];
int bits1[CELT_MAX_BANDS];
int bits2[CELT_MAX_BANDS];
int trim_offset[CELT_MAX_BANDS];
int skip_start_band = f->start_band;
int dynalloc = 6;
int alloctrim = 5;
int extrabits = 0;
int skip_bit = 0;
int intensity_stereo_bit = 0;
int dual_stereo_bit = 0;
int remaining, bandbits;
int low, high, total, done;
int totalbits;
int consumed;
int i, j;
consumed = opus_rc_tell(rc);
/* obtain spread flag */
f->spread = CELT_SPREAD_NORMAL;
if (consumed + 4 <= f->framebits)
f->spread = ff_opus_rc_dec_cdf(rc, ff_celt_model_spread);
/* generate static allocation caps */
for (i = 0; i < CELT_MAX_BANDS; i++) {
cap[i] = (ff_celt_static_caps[f->size][f->channels - 1][i] + 64)
* ff_celt_freq_range[i] << (f->channels - 1) << f->size >> 2;
}
/* obtain band boost */
totalbits = f->framebits << 3; // convert to 1/8 bits
consumed = opus_rc_tell_frac(rc);
for (i = f->start_band; i < f->end_band; i++) {
int quanta, band_dynalloc;
boost[i] = 0;
quanta = ff_celt_freq_range[i] << (f->channels - 1) << f->size;
quanta = FFMIN(quanta << 3, FFMAX(6 << 3, quanta));
band_dynalloc = dynalloc;
while (consumed + (band_dynalloc<<3) < totalbits && boost[i] < cap[i]) {
int add = ff_opus_rc_dec_log(rc, band_dynalloc);
consumed = opus_rc_tell_frac(rc);
if (!add)
break;
boost[i] += quanta;
totalbits -= quanta;
band_dynalloc = 1;
}
/* dynalloc is more likely to occur if it's already been used for earlier bands */
if (boost[i])
dynalloc = FFMAX(2, dynalloc - 1);
}
/* obtain allocation trim */
if (consumed + (6 << 3) <= totalbits)
alloctrim = ff_opus_rc_dec_cdf(rc, ff_celt_model_alloc_trim);
/* anti-collapse bit reservation */
totalbits = (f->framebits << 3) - opus_rc_tell_frac(rc) - 1;
f->anticollapse_needed = 0;
if (f->blocks > 1 && f->size >= 2 &&
totalbits >= ((f->size + 2) << 3))
f->anticollapse_needed = 1 << 3;
totalbits -= f->anticollapse_needed;
/* band skip bit reservation */
if (totalbits >= 1 << 3)
skip_bit = 1 << 3;
totalbits -= skip_bit;
/* intensity/dual stereo bit reservation */
if (f->channels == 2) {
intensity_stereo_bit = ff_celt_log2_frac[f->end_band - f->start_band];
if (intensity_stereo_bit <= totalbits) {
totalbits -= intensity_stereo_bit;
if (totalbits >= 1 << 3) {
dual_stereo_bit = 1 << 3;
totalbits -= 1 << 3;
}
} else
intensity_stereo_bit = 0;
}
for (i = f->start_band; i < f->end_band; i++) {
int trim = alloctrim - 5 - f->size;
int band = ff_celt_freq_range[i] * (f->end_band - i - 1);
int duration = f->size + 3;
int scale = duration + f->channels - 1;
/* PVQ minimum allocation threshold, below this value the band is
* skipped */
threshold[i] = FFMAX(3 * ff_celt_freq_range[i] << duration >> 4,
f->channels << 3);
trim_offset[i] = trim * (band << scale) >> 6;
if (ff_celt_freq_range[i] << f->size == 1)
trim_offset[i] -= f->channels << 3;
}
/* bisection */
low = 1;
high = CELT_VECTORS - 1;
while (low <= high) {
int center = (low + high) >> 1;
done = total = 0;
for (i = f->end_band - 1; i >= f->start_band; i--) {
bandbits = ff_celt_freq_range[i] * ff_celt_static_alloc[center][i]
<< (f->channels - 1) << f->size >> 2;
if (bandbits)
bandbits = FFMAX(0, bandbits + trim_offset[i]);
bandbits += boost[i];
if (bandbits >= threshold[i] || done) {
done = 1;
total += FFMIN(bandbits, cap[i]);
} else if (bandbits >= f->channels << 3)
total += f->channels << 3;
}
if (total > totalbits)
high = center - 1;
else
low = center + 1;
}
high = low--;
for (i = f->start_band; i < f->end_band; i++) {
bits1[i] = ff_celt_freq_range[i] * ff_celt_static_alloc[low][i]
<< (f->channels - 1) << f->size >> 2;
bits2[i] = high >= CELT_VECTORS ? cap[i] :
ff_celt_freq_range[i] * ff_celt_static_alloc[high][i]
<< (f->channels - 1) << f->size >> 2;
if (bits1[i])
bits1[i] = FFMAX(0, bits1[i] + trim_offset[i]);
if (bits2[i])
bits2[i] = FFMAX(0, bits2[i] + trim_offset[i]);
if (low)
bits1[i] += boost[i];
bits2[i] += boost[i];
if (boost[i])
skip_start_band = i;
bits2[i] = FFMAX(0, bits2[i] - bits1[i]);
}
/* bisection */
low = 0;
high = 1 << CELT_ALLOC_STEPS;
for (i = 0; i < CELT_ALLOC_STEPS; i++) {
int center = (low + high) >> 1;
done = total = 0;
for (j = f->end_band - 1; j >= f->start_band; j--) {
bandbits = bits1[j] + (center * bits2[j] >> CELT_ALLOC_STEPS);
if (bandbits >= threshold[j] || done) {
done = 1;
total += FFMIN(bandbits, cap[j]);
} else if (bandbits >= f->channels << 3)
total += f->channels << 3;
}
if (total > totalbits)
high = center;
else
low = center;
}
done = total = 0;
for (i = f->end_band - 1; i >= f->start_band; i--) {
bandbits = bits1[i] + (low * bits2[i] >> CELT_ALLOC_STEPS);
if (bandbits >= threshold[i] || done)
done = 1;
else
bandbits = (bandbits >= f->channels << 3) ?
f->channels << 3 : 0;
bandbits = FFMIN(bandbits, cap[i]);
f->pulses[i] = bandbits;
total += bandbits;
}
/* band skipping */
for (f->coded_bands = f->end_band; ; f->coded_bands--) {
int allocation;
j = f->coded_bands - 1;
if (j == skip_start_band) {
/* all remaining bands are not skipped */
totalbits += skip_bit;
break;
}
/* determine the number of bits available for coding "do not skip" markers */
remaining = totalbits - total;
bandbits = remaining / (ff_celt_freq_bands[j+1] - ff_celt_freq_bands[f->start_band]);
remaining -= bandbits * (ff_celt_freq_bands[j+1] - ff_celt_freq_bands[f->start_band]);
allocation = f->pulses[j] + bandbits * ff_celt_freq_range[j]
+ FFMAX(0, remaining - (ff_celt_freq_bands[j] - ff_celt_freq_bands[f->start_band]));
/* a "do not skip" marker is only coded if the allocation is
above the chosen threshold */
if (allocation >= FFMAX(threshold[j], (f->channels + 1) <<3 )) {
if (ff_opus_rc_dec_log(rc, 1))
break;
total += 1 << 3;
allocation -= 1 << 3;
}
/* the band is skipped, so reclaim its bits */
total -= f->pulses[j];
if (intensity_stereo_bit) {
total -= intensity_stereo_bit;
intensity_stereo_bit = ff_celt_log2_frac[j - f->start_band];
total += intensity_stereo_bit;
}
total += f->pulses[j] = (allocation >= f->channels << 3) ?
f->channels << 3 : 0;
}
/* obtain stereo flags */
f->intensity_stereo = 0;
f->dual_stereo = 0;
if (intensity_stereo_bit)
f->intensity_stereo = f->start_band +
ff_opus_rc_dec_uint(rc, f->coded_bands + 1 - f->start_band);
if (f->intensity_stereo <= f->start_band)
totalbits += dual_stereo_bit; /* no intensity stereo means no dual stereo */
else if (dual_stereo_bit)
f->dual_stereo = ff_opus_rc_dec_log(rc, 1);
/* supply the remaining bits in this frame to lower bands */
remaining = totalbits - total;
bandbits = remaining / (ff_celt_freq_bands[f->coded_bands] - ff_celt_freq_bands[f->start_band]);
remaining -= bandbits * (ff_celt_freq_bands[f->coded_bands] - ff_celt_freq_bands[f->start_band]);
for (i = f->start_band; i < f->coded_bands; i++) {
int bits = FFMIN(remaining, ff_celt_freq_range[i]);
f->pulses[i] += bits + bandbits * ff_celt_freq_range[i];
remaining -= bits;
}
for (i = f->start_band; i < f->coded_bands; i++) {
int N = ff_celt_freq_range[i] << f->size;
int prev_extra = extrabits;
f->pulses[i] += extrabits;
if (N > 1) {
int dof; // degrees of freedom
int temp; // dof * channels * log(dof)
int offset; // fine energy quantization offset, i.e.
// extra bits assigned over the standard
// totalbits/dof
int fine_bits, max_bits;
extrabits = FFMAX(0, f->pulses[i] - cap[i]);
f->pulses[i] -= extrabits;
/* intensity stereo makes use of an extra degree of freedom */
dof = N * f->channels
+ (f->channels == 2 && N > 2 && !f->dual_stereo && i < f->intensity_stereo);
temp = dof * (ff_celt_log_freq_range[i] + (f->size<<3));
offset = (temp >> 1) - dof * CELT_FINE_OFFSET;
if (N == 2) /* dof=2 is the only case that doesn't fit the model */
offset += dof<<1;
/* grant an additional bias for the first and second pulses */
if (f->pulses[i] + offset < 2 * (dof << 3))
offset += temp >> 2;
else if (f->pulses[i] + offset < 3 * (dof << 3))
offset += temp >> 3;
fine_bits = (f->pulses[i] + offset + (dof << 2)) / (dof << 3);
max_bits = FFMIN((f->pulses[i]>>3) >> (f->channels - 1),
CELT_MAX_FINE_BITS);
max_bits = FFMAX(max_bits, 0);
f->fine_bits[i] = av_clip(fine_bits, 0, max_bits);
/* if fine_bits was rounded down or capped,
give priority for the final fine energy pass */
f->fine_priority[i] = (f->fine_bits[i] * (dof<<3) >= f->pulses[i] + offset);
/* the remaining bits are assigned to PVQ */
f->pulses[i] -= f->fine_bits[i] << (f->channels - 1) << 3;
} else {
/* all bits go to fine energy except for the sign bit */
extrabits = FFMAX(0, f->pulses[i] - (f->channels << 3));
f->pulses[i] -= extrabits;
f->fine_bits[i] = 0;
f->fine_priority[i] = 1;
}
/* hand back a limited number of extra fine energy bits to this band */
if (extrabits > 0) {
int fineextra = FFMIN(extrabits >> (f->channels + 2),
CELT_MAX_FINE_BITS - f->fine_bits[i]);
f->fine_bits[i] += fineextra;
fineextra <<= f->channels + 2;
f->fine_priority[i] = (fineextra >= extrabits - prev_extra);
extrabits -= fineextra;
}
}
f->remaining = extrabits;
/* skipped bands dedicate all of their bits for fine energy */
for (; i < f->end_band; i++) {
f->fine_bits[i] = f->pulses[i] >> (f->channels - 1) >> 3;
f->pulses[i] = 0;
f->fine_priority[i] = f->fine_bits[i] < 1;
}
}
static void celt_denormalize(CeltFrame *f, CeltBlock *block, float *data)
{
int i, j;
for (i = f->start_band; i < f->end_band; i++) {
float *dst = data + (ff_celt_freq_bands[i] << f->size);
float norm = exp2(block->energy[i] + ff_celt_mean_energy[i]);
for (j = 0; j < ff_celt_freq_range[i] << f->size; j++)
dst[j] *= norm;
}
}
static void celt_postfilter_apply_transition(CeltBlock *block, float *data)
{
const int T0 = block->pf_period_old;
const int T1 = block->pf_period;
float g00, g01, g02;
float g10, g11, g12;
float x0, x1, x2, x3, x4;
int i;
if (block->pf_gains[0] == 0.0 &&
block->pf_gains_old[0] == 0.0)
return;
g00 = block->pf_gains_old[0];
g01 = block->pf_gains_old[1];
g02 = block->pf_gains_old[2];
g10 = block->pf_gains[0];
g11 = block->pf_gains[1];
g12 = block->pf_gains[2];
x1 = data[-T1 + 1];
x2 = data[-T1];
x3 = data[-T1 - 1];
x4 = data[-T1 - 2];
for (i = 0; i < CELT_OVERLAP; i++) {
float w = ff_celt_window2[i];
x0 = data[i - T1 + 2];
data[i] += (1.0 - w) * g00 * data[i - T0] +
(1.0 - w) * g01 * (data[i - T0 - 1] + data[i - T0 + 1]) +
(1.0 - w) * g02 * (data[i - T0 - 2] + data[i - T0 + 2]) +
w * g10 * x2 +
w * g11 * (x1 + x3) +
w * g12 * (x0 + x4);
x4 = x3;
x3 = x2;
x2 = x1;
x1 = x0;
}
}
static void celt_postfilter_apply(CeltBlock *block, float *data, int len)
{
const int T = block->pf_period;
float g0, g1, g2;
float x0, x1, x2, x3, x4;
int i;
if (block->pf_gains[0] == 0.0 || len <= 0)
return;
g0 = block->pf_gains[0];
g1 = block->pf_gains[1];
g2 = block->pf_gains[2];
x4 = data[-T - 2];
x3 = data[-T - 1];
x2 = data[-T];
x1 = data[-T + 1];
for (i = 0; i < len; i++) {
x0 = data[i - T + 2];
data[i] += g0 * x2 +
g1 * (x1 + x3) +
g2 * (x0 + x4);
x4 = x3;
x3 = x2;
x2 = x1;
x1 = x0;
}
}
static void celt_postfilter(CeltFrame *f, CeltBlock *block)
{
int len = f->blocksize * f->blocks;
celt_postfilter_apply_transition(block, block->buf + 1024);
block->pf_period_old = block->pf_period;
memcpy(block->pf_gains_old, block->pf_gains, sizeof(block->pf_gains));
block->pf_period = block->pf_period_new;
memcpy(block->pf_gains, block->pf_gains_new, sizeof(block->pf_gains));
if (len > CELT_OVERLAP) {
celt_postfilter_apply_transition(block, block->buf + 1024 + CELT_OVERLAP);
celt_postfilter_apply(block, block->buf + 1024 + 2 * CELT_OVERLAP,
len - 2 * CELT_OVERLAP);
block->pf_period_old = block->pf_period;
memcpy(block->pf_gains_old, block->pf_gains, sizeof(block->pf_gains));
}
memmove(block->buf, block->buf + len, (1024 + CELT_OVERLAP / 2) * sizeof(float));
}
static int parse_postfilter(CeltFrame *f, OpusRangeCoder *rc, int consumed)
{
static const float postfilter_taps[3][3] = {
{ 0.3066406250f, 0.2170410156f, 0.1296386719f },
{ 0.4638671875f, 0.2680664062f, 0.0 },
{ 0.7998046875f, 0.1000976562f, 0.0 }
};
int i;
memset(f->block[0].pf_gains_new, 0, sizeof(f->block[0].pf_gains_new));
memset(f->block[1].pf_gains_new, 0, sizeof(f->block[1].pf_gains_new));
if (f->start_band == 0 && consumed + 16 <= f->framebits) {
int has_postfilter = ff_opus_rc_dec_log(rc, 1);
if (has_postfilter) {
float gain;
int tapset, octave, period;
octave = ff_opus_rc_dec_uint(rc, 6);
period = (16 << octave) + ff_opus_rc_get_raw(rc, 4 + octave) - 1;
gain = 0.09375f * (ff_opus_rc_get_raw(rc, 3) + 1);
tapset = (opus_rc_tell(rc) + 2 <= f->framebits) ?
ff_opus_rc_dec_cdf(rc, ff_celt_model_tapset) : 0;
for (i = 0; i < 2; i++) {
CeltBlock *block = &f->block[i];
block->pf_period_new = FFMAX(period, CELT_POSTFILTER_MINPERIOD);
block->pf_gains_new[0] = gain * postfilter_taps[tapset][0];
block->pf_gains_new[1] = gain * postfilter_taps[tapset][1];
block->pf_gains_new[2] = gain * postfilter_taps[tapset][2];
}
}
consumed = opus_rc_tell(rc);
}
return consumed;
}
static void process_anticollapse(CeltFrame *f, CeltBlock *block, float *X)
{
int i, j, k;
for (i = f->start_band; i < f->end_band; i++) {
int renormalize = 0;
float *xptr;
float prev[2];
float Ediff, r;
float thresh, sqrt_1;
int depth;
/* depth in 1/8 bits */
depth = (1 + f->pulses[i]) / (ff_celt_freq_range[i] << f->size);
thresh = exp2f(-1.0 - 0.125f * depth);
sqrt_1 = 1.0f / sqrtf(ff_celt_freq_range[i] << f->size);
xptr = X + (ff_celt_freq_bands[i] << f->size);
prev[0] = block->prev_energy[0][i];
prev[1] = block->prev_energy[1][i];
if (f->channels == 1) {
CeltBlock *block1 = &f->block[1];
prev[0] = FFMAX(prev[0], block1->prev_energy[0][i]);
prev[1] = FFMAX(prev[1], block1->prev_energy[1][i]);
}
Ediff = block->energy[i] - FFMIN(prev[0], prev[1]);
Ediff = FFMAX(0, Ediff);
/* r needs to be multiplied by 2 or 2*sqrt(2) depending on LM because
short blocks don't have the same energy as long */
r = exp2(1 - Ediff);
if (f->size == 3)
r *= M_SQRT2;
r = FFMIN(thresh, r) * sqrt_1;
for (k = 0; k < 1 << f->size; k++) {
/* Detect collapse */
if (!(block->collapse_masks[i] & 1 << k)) {
/* Fill with noise */
for (j = 0; j < ff_celt_freq_range[i]; j++)
xptr[(j << f->size) + k] = (celt_rng(f) & 0x8000) ? r : -r;
renormalize = 1;
}
}
/* We just added some energy, so we need to renormalize */
if (renormalize)
celt_renormalize_vector(xptr, ff_celt_freq_range[i] << f->size, 1.0f);
}
}
static void celt_decode_bands(CeltFrame *f, OpusRangeCoder *rc)
{
float lowband_scratch[8 * 22];
float norm[2 * 8 * 100];
int totalbits = (f->framebits << 3) - f->anticollapse_needed;
int update_lowband = 1;
int lowband_offset = 0;
int i, j;
memset(f->block[0].coeffs, 0, sizeof(f->block[0].coeffs));
memset(f->block[1].coeffs, 0, sizeof(f->block[0].coeffs));
for (i = f->start_band; i < f->end_band; i++) {
int band_offset = ff_celt_freq_bands[i] << f->size;
int band_size = ff_celt_freq_range[i] << f->size;
float *X = f->block[0].coeffs + band_offset;
float *Y = (f->channels == 2) ? f->block[1].coeffs + band_offset : NULL;
int consumed = opus_rc_tell_frac(rc);
float *norm2 = norm + 8 * 100;
int effective_lowband = -1;
unsigned int cm[2];
int b;
/* Compute how many bits we want to allocate to this band */
if (i != f->start_band)
f->remaining -= consumed;
f->remaining2 = totalbits - consumed - 1;
if (i <= f->coded_bands - 1) {
int curr_balance = f->remaining / FFMIN(3, f->coded_bands-i);
b = av_clip_uintp2(FFMIN(f->remaining2 + 1, f->pulses[i] + curr_balance), 14);
} else
b = 0;
if (ff_celt_freq_bands[i] - ff_celt_freq_range[i] >= ff_celt_freq_bands[f->start_band] &&
(update_lowband || lowband_offset == 0))
lowband_offset = i;
/* Get a conservative estimate of the collapse_mask's for the bands we're
going to be folding from. */
if (lowband_offset != 0 && (f->spread != CELT_SPREAD_AGGRESSIVE ||
f->blocks > 1 || f->tf_change[i] < 0)) {
int foldstart, foldend;
/* This ensures we never repeat spectral content within one band */
effective_lowband = FFMAX(ff_celt_freq_bands[f->start_band],
ff_celt_freq_bands[lowband_offset] - ff_celt_freq_range[i]);
foldstart = lowband_offset;
while (ff_celt_freq_bands[--foldstart] > effective_lowband);
foldend = lowband_offset - 1;
while (ff_celt_freq_bands[++foldend] < effective_lowband + ff_celt_freq_range[i]);
cm[0] = cm[1] = 0;
for (j = foldstart; j < foldend; j++) {
cm[0] |= f->block[0].collapse_masks[j];
cm[1] |= f->block[f->channels - 1].collapse_masks[j];
}
} else
/* Otherwise, we'll be using the LCG to fold, so all blocks will (almost
always) be non-zero.*/
cm[0] = cm[1] = (1 << f->blocks) - 1;
if (f->dual_stereo && i == f->intensity_stereo) {
/* Switch off dual stereo to do intensity */
f->dual_stereo = 0;
for (j = ff_celt_freq_bands[f->start_band] << f->size; j < band_offset; j++)
norm[j] = (norm[j] + norm2[j]) / 2;
}
if (f->dual_stereo) {
cm[0] = ff_celt_decode_band(f, rc, i, X, NULL, band_size, b / 2, f->blocks,
effective_lowband != -1 ? norm + (effective_lowband << f->size) : NULL, f->size,
norm + band_offset, 0, 1.0f, lowband_scratch, cm[0]);
cm[1] = ff_celt_decode_band(f, rc, i, Y, NULL, band_size, b/2, f->blocks,
effective_lowband != -1 ? norm2 + (effective_lowband << f->size) : NULL, f->size,
norm2 + band_offset, 0, 1.0f, lowband_scratch, cm[1]);
} else {
cm[0] = ff_celt_decode_band(f, rc, i, X, Y, band_size, b, f->blocks,
effective_lowband != -1 ? norm + (effective_lowband << f->size) : NULL, f->size,
norm + band_offset, 0, 1.0f, lowband_scratch, cm[0]|cm[1]);
cm[1] = cm[0];
}
f->block[0].collapse_masks[i] = (uint8_t)cm[0];
f->block[f->channels - 1].collapse_masks[i] = (uint8_t)cm[1];
f->remaining += f->pulses[i] + consumed;
/* Update the folding position only as long as we have 1 bit/sample depth */
update_lowband = (b > band_size << 3);
}
}
int ff_celt_decode_frame(CeltFrame *f, OpusRangeCoder *rc,
float **output, int channels, int frame_size,
int start_band, int end_band)
{
int i, j;
int consumed; // bits of entropy consumed thus far for this frame
MDCT15Context *imdct;
float imdct_scale = 1.0;
if (channels != 1 && channels != 2) {
av_log(f->avctx, AV_LOG_ERROR, "Invalid number of coded channels: %d\n",
channels);
return AVERROR_INVALIDDATA;
}
if (start_band < 0 || start_band > end_band || end_band > CELT_MAX_BANDS) {
av_log(f->avctx, AV_LOG_ERROR, "Invalid start/end band: %d %d\n",
start_band, end_band);
return AVERROR_INVALIDDATA;
}
f->silence = 0;
f->transient = 0;
f->anticollapse = 0;
f->flushed = 0;
f->channels = channels;
f->start_band = start_band;
f->end_band = end_band;
f->framebits = rc->rb.bytes * 8;
f->size = av_log2(frame_size / CELT_SHORT_BLOCKSIZE);
if (f->size > CELT_MAX_LOG_BLOCKS ||
frame_size != CELT_SHORT_BLOCKSIZE * (1 << f->size)) {
av_log(f->avctx, AV_LOG_ERROR, "Invalid CELT frame size: %d\n",
frame_size);
return AVERROR_INVALIDDATA;
}
if (!f->output_channels)
f->output_channels = channels;
memset(f->block[0].collapse_masks, 0, sizeof(f->block[0].collapse_masks));
memset(f->block[1].collapse_masks, 0, sizeof(f->block[1].collapse_masks));
consumed = opus_rc_tell(rc);
/* obtain silence flag */
if (consumed >= f->framebits)
f->silence = 1;
else if (consumed == 1)
f->silence = ff_opus_rc_dec_log(rc, 15);
if (f->silence) {
consumed = f->framebits;
rc->total_bits += f->framebits - opus_rc_tell(rc);
}
/* obtain post-filter options */
consumed = parse_postfilter(f, rc, consumed);
/* obtain transient flag */
if (f->size != 0 && consumed+3 <= f->framebits)
f->transient = ff_opus_rc_dec_log(rc, 3);
f->blocks = f->transient ? 1 << f->size : 1;
f->blocksize = frame_size / f->blocks;
imdct = f->imdct[f->transient ? 0 : f->size];
if (channels == 1) {
for (i = 0; i < CELT_MAX_BANDS; i++)
f->block[0].energy[i] = FFMAX(f->block[0].energy[i], f->block[1].energy[i]);
}
celt_decode_coarse_energy(f, rc);
celt_decode_tf_changes (f, rc);
celt_decode_allocation (f, rc);
celt_decode_fine_energy (f, rc);
celt_decode_bands (f, rc);
if (f->anticollapse_needed)
f->anticollapse = ff_opus_rc_get_raw(rc, 1);
celt_decode_final_energy(f, rc);
/* apply anti-collapse processing and denormalization to
* each coded channel */
for (i = 0; i < f->channels; i++) {
CeltBlock *block = &f->block[i];
if (f->anticollapse)
process_anticollapse(f, block, f->block[i].coeffs);
celt_denormalize(f, block, f->block[i].coeffs);
}
/* stereo -> mono downmix */
if (f->output_channels < f->channels) {
f->dsp->vector_fmac_scalar(f->block[0].coeffs, f->block[1].coeffs, 1.0, FFALIGN(frame_size, 16));
imdct_scale = 0.5;
} else if (f->output_channels > f->channels)
memcpy(f->block[1].coeffs, f->block[0].coeffs, frame_size * sizeof(float));
if (f->silence) {
for (i = 0; i < 2; i++) {
CeltBlock *block = &f->block[i];
for (j = 0; j < FF_ARRAY_ELEMS(block->energy); j++)
block->energy[j] = CELT_ENERGY_SILENCE;
}
memset(f->block[0].coeffs, 0, sizeof(f->block[0].coeffs));
memset(f->block[1].coeffs, 0, sizeof(f->block[1].coeffs));
}
/* transform and output for each output channel */
for (i = 0; i < f->output_channels; i++) {
CeltBlock *block = &f->block[i];
float m = block->emph_coeff;
/* iMDCT and overlap-add */
for (j = 0; j < f->blocks; j++) {
float *dst = block->buf + 1024 + j * f->blocksize;
imdct->imdct_half(imdct, dst + CELT_OVERLAP / 2, f->block[i].coeffs + j,
f->blocks, imdct_scale);
f->dsp->vector_fmul_window(dst, dst, dst + CELT_OVERLAP / 2,
ff_celt_window, CELT_OVERLAP / 2);
}
/* postfilter */
celt_postfilter(f, block);
/* deemphasis and output scaling */
for (j = 0; j < frame_size; j++) {
float tmp = block->buf[1024 - frame_size + j] + m;
m = tmp * CELT_EMPH_COEFF;
output[i][j] = tmp / 32768.;
}
block->emph_coeff = m;
}
if (channels == 1)
memcpy(f->block[1].energy, f->block[0].energy, sizeof(f->block[0].energy));
for (i = 0; i < 2; i++ ) {
CeltBlock *block = &f->block[i];
if (!f->transient) {
memcpy(block->prev_energy[1], block->prev_energy[0], sizeof(block->prev_energy[0]));
memcpy(block->prev_energy[0], block->energy, sizeof(block->prev_energy[0]));
} else {
for (j = 0; j < CELT_MAX_BANDS; j++)
block->prev_energy[0][j] = FFMIN(block->prev_energy[0][j], block->energy[j]);
}
for (j = 0; j < f->start_band; j++) {
block->prev_energy[0][j] = CELT_ENERGY_SILENCE;
block->energy[j] = 0.0;
}
for (j = f->end_band; j < CELT_MAX_BANDS; j++) {
block->prev_energy[0][j] = CELT_ENERGY_SILENCE;
block->energy[j] = 0.0;
}
}
f->seed = rc->range;
return 0;
}
void ff_celt_flush(CeltFrame *f)
{
int i, j;
if (f->flushed)
return;
for (i = 0; i < 2; i++) {
CeltBlock *block = &f->block[i];
for (j = 0; j < CELT_MAX_BANDS; j++)
block->prev_energy[0][j] = block->prev_energy[1][j] = CELT_ENERGY_SILENCE;
memset(block->energy, 0, sizeof(block->energy));
memset(block->buf, 0, sizeof(block->buf));
memset(block->pf_gains, 0, sizeof(block->pf_gains));
memset(block->pf_gains_old, 0, sizeof(block->pf_gains_old));
memset(block->pf_gains_new, 0, sizeof(block->pf_gains_new));
block->emph_coeff = 0.0;
}
f->seed = 0;
f->flushed = 1;
}
void ff_celt_free(CeltFrame **f)
{
CeltFrame *frm = *f;
int i;
if (!frm)
return;
for (i = 0; i < FF_ARRAY_ELEMS(frm->imdct); i++)
ff_mdct15_uninit(&frm->imdct[i]);
av_freep(&frm->dsp);
av_freep(f);
}
int ff_celt_init(AVCodecContext *avctx, CeltFrame **f, int output_channels)
{
CeltFrame *frm;
int i, ret;
if (output_channels != 1 && output_channels != 2) {
av_log(avctx, AV_LOG_ERROR, "Invalid number of output channels: %d\n",
output_channels);
return AVERROR(EINVAL);
}
frm = av_mallocz(sizeof(*frm));
if (!frm)
return AVERROR(ENOMEM);
frm->avctx = avctx;
frm->output_channels = output_channels;
for (i = 0; i < FF_ARRAY_ELEMS(frm->imdct); i++) {
ret = ff_mdct15_init(&frm->imdct[i], 1, i + 3, -1.0f);
if (ret < 0)
goto fail;
}
frm->dsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
if (!frm->dsp) {
ret = AVERROR(ENOMEM);
goto fail;
}
ff_celt_flush(frm);
*f = frm;
return 0;
fail:
ff_celt_free(&frm);
return ret;
}
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