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1b8649c2ce
FFmpeg/libavcodec/opus_celt.c
Rostislav Pehlivanov 1b8649c2ce opus: add an option to toggle intensity stereo phase inversion 
Due to a somewhat high volume of complains, phase inversion has
been made optional with RFC8251. This allows for better bass
frequency response when partially downmixing to play on systems
with an LFE speaker.

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
2017-12-04 07:28:45 +00:00

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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"
/* Use the 2D z-transform to apply prediction in both the time domain (alpha)
* and the frequency domain (beta) */
static void celt_decode_coarse_energy(CeltFrame *f, OpusRangeCoder *rc)
{
int i, j;
float prev[2] = { 0 };
float alpha = ff_celt_alpha_coef[f->size];
float beta = ff_celt_beta_coef[f->size];
const uint8_t *model = ff_celt_coarse_energy_dist[f->size][0];
/* intra frame */
if (opus_rc_tell(rc) + 3 <= f->framebits && ff_opus_rc_dec_log(rc, 3)) {
alpha = 0.0f;
beta = 1.0f - (4915.0f/32768.0f);
model = ff_celt_coarse_energy_dist[f->size][1];
}
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 log_norm = block->energy[i] + ff_celt_mean_energy[i];
float norm = exp2f(FFMIN(log_norm, 32.0f));
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)
{
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 * ff_celt_postfilter_taps[tapset][0];
block->pf_gains_new[1] = gain * ff_celt_postfilter_taps[tapset][1];
block->pf_gains_new[2] = gain * ff_celt_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 = exp2f(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++) {
uint32_t cm[2] = { (1 << f->blocks) - 1, (1 << f->blocks) - 1 };
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;
int b = 0;
/* 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);
}
if ((ff_celt_freq_bands[i] - ff_celt_freq_range[i] >= ff_celt_freq_bands[f->start_band] ||
i == f->start_band + 1) && (update_lowband || lowband_offset == 0))
lowband_offset = i;
if (i == f->start_band + 1) {
/* Special Hybrid Folding (RFC 8251 section 9). Copy the first band into
the second to ensure the second band never has to use the LCG. */
int offset = 8 * ff_celt_freq_bands[i];
int count = 8 * (ff_celt_freq_range[i] - ff_celt_freq_range[i-1]);
memcpy(&norm[offset], &norm[offset - count], count * sizeof(float));
if (f->channels == 2)
memcpy(&norm2[offset], &norm2[offset - count], count * sizeof(float));
}
/* 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 (++foldend < i && 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];
}
}
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] = f->pvq->decode_band(f->pvq, 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] = f->pvq->decode_band(f->pvq, 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] = f->pvq->decode_band(f->pvq, 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, downmix = 0;
int consumed; // bits of entropy consumed thus far for this frame
MDCT15Context *imdct;
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));
downmix = 1;
} 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);
f->dsp->vector_fmul_window(dst, dst, dst + CELT_OVERLAP / 2,
ff_celt_window, CELT_OVERLAP / 2);
}
if (downmix)
f->dsp->vector_fmul_scalar(&block->buf[1024], &block->buf[1024], 0.5f, frame_size);
/* postfilter */
celt_postfilter(f, block);
/* deemphasis and output scaling */
for (j = 0; j < frame_size; j++) {
const float tmp = block->buf[1024 - frame_size + j] + m;
m = tmp * CELT_EMPH_COEFF;
output[i][j] = tmp;
}
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]);
ff_celt_pvq_uninit(&frm->pvq);
av_freep(&frm->dsp);
av_freep(f);
}
int ff_celt_init(AVCodecContext *avctx, CeltFrame **f, int output_channels,
int apply_phase_inv)
{
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;
frm->apply_phase_inv = apply_phase_inv;
for (i = 0; i < FF_ARRAY_ELEMS(frm->imdct); i++)
if ((ret = ff_mdct15_init(&frm->imdct[i], 1, i + 3, -1.0f/32768)) < 0)
goto fail;
if ((ret = ff_celt_pvq_init(&frm->pvq)) < 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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