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/*
* AAC encoder main-type prediction
* Copyright (C) 2015 Rostislav Pehlivanov
*
* 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
* AAC encoder main prediction
* @author Rostislav Pehlivanov ( atomnuker gmail com )
*/
#include "aactab.h"
#include "aacenc_pred.h"
#include "aacenc_utils.h"
#include "aacenc_quantization.h"
static inline float flt16_round(float pf)
{
union av_intfloat32 tmp;
tmp.f = pf;
tmp.i = (tmp.i + 0x00008000U) & 0xFFFF0000U;
return tmp.f;
}
static inline float flt16_even(float pf)
{
union av_intfloat32 tmp;
tmp.f = pf;
tmp.i = (tmp.i + 0x00007FFFU + (tmp.i & 0x00010000U >> 16)) & 0xFFFF0000U;
return tmp.f;
}
static inline float flt16_trunc(float pf)
{
union av_intfloat32 pun;
pun.f = pf;
pun.i &= 0xFFFF0000U;
return pun.f;
}
static inline void predict(PredictorState *ps, float *coef, float *rcoef,
int output_enable)
{
const float a = 0.953125; // 61.0 / 64
float k2;
float r0 = ps->r0, r1 = ps->r1;
float cor0 = ps->cor0, cor1 = ps->cor1;
float var0 = ps->var0, var1 = ps->var1;
ps->k1 = var0 > 1 ? cor0 * flt16_even(a / var0) : 0;
k2 = var1 > 1 ? cor1 * flt16_even(a / var1) : 0;
ps->x_est = flt16_round(ps->k1*r0 + k2*r1);
if (output_enable)
*coef -= ps->x_est;
else
*rcoef = *coef - ps->x_est;
}
static inline void update_predictor(PredictorState *ps, float qcoef)
{
const float alpha = 0.90625; // 29.0 / 32
const float a = 0.953125; // 61.0 / 64
float k1 = ps->k1;
float r0 = ps->r0;
float r1 = ps->r1;
float e0 = qcoef + ps->x_est;
float e1 = e0 - k1 * r0;
float cor0 = ps->cor0, cor1 = ps->cor1;
float var0 = ps->var0, var1 = ps->var1;
ps->cor1 = flt16_trunc(alpha * cor1 + r1 * e1);
ps->var1 = flt16_trunc(alpha * var1 + 0.5f * (r1 * r1 + e1 * e1));
ps->cor0 = flt16_trunc(alpha * cor0 + r0 * e0);
ps->var0 = flt16_trunc(alpha * var0 + 0.5f * (r0 * r0 + e0 * e0));
ps->r1 = flt16_trunc(a * (r0 - k1 * e0));
ps->r0 = flt16_trunc(a * e0);
}
static inline void reset_predict_state(PredictorState *ps)
{
ps->r0 = 0.0f;
ps->r1 = 0.0f;
ps->cor0 = 0.0f;
ps->cor1 = 0.0f;
ps->var0 = 1.0f;
ps->var1 = 1.0f;
ps->k1 = 0.0f;
ps->x_est= 0.0f;
}
static inline void reset_all_predictors(SingleChannelElement *sce)
{
int i;
for (i = 0; i < MAX_PREDICTORS; i++)
reset_predict_state(&sce->predictor_state[i]);
for (i = 1; i < 31; i++)
sce->ics.predictor_reset_count[i] = 0;
}
static inline void reset_predictor_group(SingleChannelElement *sce, int group_num)
{
int i;
PredictorState *ps = sce->predictor_state;
sce->ics.predictor_reset_count[group_num] = 0;
for (i = group_num - 1; i < MAX_PREDICTORS; i += 30)
reset_predict_state(&ps[i]);
}
void ff_aac_apply_main_pred(AACEncContext *s, SingleChannelElement *sce)
{
int sfb, k;
if (sce->ics.window_sequence[0] != EIGHT_SHORT_SEQUENCE) {
for (sfb = 0; sfb < ff_aac_pred_sfb_max[s->samplerate_index]; sfb++) {
for (k = sce->ics.swb_offset[sfb]; k < sce->ics.swb_offset[sfb + 1]; k++)
predict(&sce->predictor_state[k], &sce->coeffs[k], &sce->prcoeffs[k],
(sce->ics.predictor_present && sce->ics.prediction_used[sfb]));
}
}
}
static void decode_joint_stereo(ChannelElement *cpe)
{
int i, w, w2, g;
SingleChannelElement *sce0 = &cpe->ch[0];
SingleChannelElement *sce1 = &cpe->ch[1];
IndividualChannelStream *ics;
for (i = 0; i < MAX_PREDICTORS; i++)
sce0->prcoeffs[i] = sce0->predictor_state[i].x_est;
ics = &sce0->ics;
for (w = 0; w < ics->num_windows; w += ics->group_len[w]) {
for (w2 = 0; w2 < ics->group_len[w]; w2++) {
int start = (w+w2) * 128;
for (g = 0; g < ics->num_swb; g++) {
int sfb = w*16 + g;
//apply Intensity stereo coeffs transformation
if (cpe->is_mask[sfb]) {
int p = -1 + 2 * (sce1->band_type[sfb] - 14);
float rscale = ff_aac_pow2sf_tab[-sce1->sf_idx[sfb] + POW_SF2_ZERO];
p *= 1 - 2 * cpe->ms_mask[sfb];
for (i = 0; i < ics->swb_sizes[g]; i++) {
sce0->pqcoeffs[start+i] = (sce0->prcoeffs[start+i] + p*sce0->pqcoeffs[start+i]) * rscale;
}
} else if (cpe->ms_mask[sfb] &&
sce0->band_type[sfb] < NOISE_BT &&
sce1->band_type[sfb] < NOISE_BT) {
for (i = 0; i < ics->swb_sizes[g]; i++) {
float L = sce0->pqcoeffs[start+i] + sce1->pqcoeffs[start+i];
float R = sce0->pqcoeffs[start+i] - sce1->pqcoeffs[start+i];
sce0->pqcoeffs[start+i] = L;
sce1->pqcoeffs[start+i] = R;
}
}
start += ics->swb_sizes[g];
}
}
}
}
static inline void prepare_predictors(SingleChannelElement *sce)
{
int k;
for (k = 0; k < MAX_PREDICTORS; k++)
predict(&sce->predictor_state[k], &sce->coeffs[k], &sce->prcoeffs[k], 0);
}
void ff_aac_update_main_pred(AACEncContext *s, SingleChannelElement *sce, ChannelElement *cpe)
{
int k;
if (sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE)
return;
if (cpe && cpe->common_window)
decode_joint_stereo(cpe);
for (k = 0; k < MAX_PREDICTORS; k++)
update_predictor(&sce->predictor_state[k], sce->pqcoeffs[k]);
if (sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE) {
reset_all_predictors(sce);
}
if (sce->ics.predictor_reset_group)
reset_predictor_group(sce, sce->ics.predictor_reset_group);
}
/* If inc == 0 check if it returns 0 to see if you can reset freely */
static inline int update_counters(IndividualChannelStream *ics, int inc)
{
int i, rg = 0;
for (i = 1; i < 31; i++) {
ics->predictor_reset_count[i] += inc;
if (!rg && ics->predictor_reset_count[i] > PRED_RESET_FRAME_MIN)
rg = i; /* Reset this immediately */
}
return rg;
}
void ff_aac_adjust_common_prediction(AACEncContext *s, ChannelElement *cpe)
{
int start, w, g, count = 0;
SingleChannelElement *sce0 = &cpe->ch[0];
SingleChannelElement *sce1 = &cpe->ch[1];
if (!cpe->common_window || sce0->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE)
return;
/* Predict if IS or MS is on and at least one channel is marked or when both are */
for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
start = 0;
for (g = 0; g < sce0->ics.num_swb; g++) {
int sfb = w*16+g;
if (sfb < PRED_SFB_START || sfb > ff_aac_pred_sfb_max[s->samplerate_index]) {
;
} else if ((cpe->is_mask[sfb] || cpe->ms_mask[sfb]) &&
(sce0->ics.prediction_used[sfb] || sce1->ics.prediction_used[sfb])) {
sce0->ics.prediction_used[sfb] = sce1->ics.prediction_used[sfb] = 1;
count++;
} else if (sce0->ics.prediction_used[sfb] && sce1->ics.prediction_used[sfb]) {
count++;
} else {
/* Restore band types, if changed - prediction never sets > RESERVED_BT */
if (sce0->ics.prediction_used[sfb] && sce0->band_type[sfb] < RESERVED_BT)
sce0->band_type[sfb] = sce0->orig_band_type[sfb];
if (sce1->ics.prediction_used[sfb] && sce1->band_type[sfb] < RESERVED_BT)
sce1->band_type[sfb] = sce1->orig_band_type[sfb];
sce0->ics.prediction_used[sfb] = sce1->ics.prediction_used[sfb] = 0;
}
start += sce0->ics.swb_sizes[g];
}
}
sce1->ics.predictor_present = sce0->ics.predictor_present = !!count;
if (!count)
return;
sce1->ics.predictor_reset_group = sce0->ics.predictor_reset_group;
}
static void update_pred_resets(SingleChannelElement *sce)
{
int i, max_group_id_c, max_frame = 0;
float avg_frame = 0.0f;
IndividualChannelStream *ics = &sce->ics;
/* Some other code probably chose the reset group */
if (ics->predictor_reset_group)
return;
if ((ics->predictor_reset_group = update_counters(&sce->ics, 1)))
return;
for (i = 1; i < 31; i++) {
if (ics->predictor_reset_count[i] > max_frame) {
max_group_id_c = i;
max_frame = ics->predictor_reset_count[i];
}
avg_frame = (ics->predictor_reset_count[i] + avg_frame)/2;
}
if (avg_frame*2 > max_frame && max_frame > PRED_RESET_MIN ||
max_frame > (2*PRED_RESET_MIN)/3) {
ics->predictor_reset_group = max_group_id_c;
} else {
ics->predictor_reset_group = 0;
}
}
void ff_aac_search_for_pred(AACEncContext *s, SingleChannelElement *sce)
{
int sfb, i, count = 0;
float *O34 = &s->scoefs[256*0], *P34 = &s->scoefs[256*1];
int cost_coeffs = PRICE_OFFSET;
int cost_pred = 1+(sce->ics.predictor_reset_group ? 5 : 0) +
FFMIN(sce->ics.max_sfb, ff_aac_pred_sfb_max[s->samplerate_index]);
memcpy(sce->orig_band_type, sce->band_type, 128*sizeof(enum BandType));
if (!sce->ics.predictor_initialized ||
sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE) {
reset_all_predictors(sce);
for (i = 1; i < 31; i++)
sce->ics.predictor_reset_count[i] = i;
sce->ics.predictor_initialized = 1;
}
update_pred_resets(sce);
prepare_predictors(sce);
sce->ics.predictor_reset_group = 0;
for (sfb = PRED_SFB_START; sfb < ff_aac_pred_sfb_max[s->samplerate_index]; sfb++) {
float dist1 = 0.0f, dist2 = 0.0f;
int swb_start = sce->ics.swb_offset[sfb];
int swb_len = sce->ics.swb_offset[sfb + 1] - swb_start;
int cb1 = sce->band_type[sfb], cb2, bits1 = 0, bits2 = 0;
FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[sfb];
abs_pow34_v(O34, &sce->coeffs[swb_start], swb_len);
abs_pow34_v(P34, &sce->prcoeffs[swb_start], swb_len);
cb2 = find_min_book(find_max_val(1, swb_len, P34), sce->sf_idx[sfb]);
if (cb2 <= cb1) {
dist1 += quantize_band_cost(s, &sce->coeffs[swb_start], O34, swb_len,
sce->sf_idx[sfb], cb1, s->lambda / band->threshold,
INFINITY, &bits1, 0);
dist2 += quantize_band_cost(s, &sce->prcoeffs[swb_start], P34, swb_len,
sce->sf_idx[sfb], cb2, s->lambda / band->threshold,
INFINITY, &bits2, 0);
if (dist2 <= dist1) {
sce->ics.prediction_used[sfb] = 1;
sce->band_type[sfb] = cb2;
count++;
}
cost_coeffs += bits1;
cost_pred += bits2;
}
}
if (count && cost_pred > cost_coeffs) {
memset(sce->ics.prediction_used, 0, sizeof(sce->ics.prediction_used));
memcpy(sce->band_type, sce->orig_band_type, sizeof(sce->band_type));
count = 0;
}
sce->ics.predictor_present = !!count;
}
/**
* Encoder predictors data.
*/
void ff_aac_encode_main_pred(AACEncContext *s, SingleChannelElement *sce)
{
int sfb;
if (!sce->ics.predictor_present ||
sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE)
return;
put_bits(&s->pb, 1, !!sce->ics.predictor_reset_group);
if (sce->ics.predictor_reset_group)
put_bits(&s->pb, 5, sce->ics.predictor_reset_group);
for (sfb = 0; sfb < FFMIN(sce->ics.max_sfb, ff_aac_pred_sfb_max[s->samplerate_index]); sfb++)
put_bits(&s->pb, 1, sce->ics.prediction_used[sfb]);
}