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ffmpeg/libavcodec/aacenc_pred.c
Rostislav Pehlivanov 4565611b04 aacenc_is: add a flag to use pure coefficients instead 
This commit adds a flag to use the pure coefficients instead
of the processed ones (sce->coeffs). This is needed because
IS will apply the changes to the coefficients immediately
before the adjust_common_prediction function and it doesn't
make sense to measure stereo channel coefficient difference
when one of the channels coefficients are all zero.

Therefore add a flag to use pure coefficients in that case.
TNS is the only thing touching the coefficients before IS
so common window prediction will not take that into account
but the effect of the TNS filter per coefficient can be small
(a few percent) so to some approximation it's fine to just
ignore that.

Also fixed a small error which doesn't alter the results
that much. pow(sqrt(number), 3.0/4.0) == pow(number, 3.0/8.0) !=
pow(number, 3.0/4.0).

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
2015-09-05 08:32:09 +01:00

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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 Intensity Stereo
* @author Rostislav Pehlivanov ( atomnuker gmail com )
*/
#include "aactab.h"
#include "aacenc_pred.h"
#include "aacenc_utils.h"
#include "aacenc_is.h" /* <- Needed for common window distortions */
#include "aacenc_quantization.h"
#define RESTORE_PRED(sce, sfb) \
if (sce->ics.prediction_used[sfb]) {\
sce->ics.prediction_used[sfb] = 0;\
sce->band_type[sfb] = sce->band_alt[sfb];\
}
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 set)
{
float k2;
const float a = 0.953125; // 61.0 / 64
const float alpha = 0.90625; // 29.0 / 32
const float k1 = ps->k1;
const float r0 = ps->r0, r1 = ps->r1;
const float cor0 = ps->cor0, cor1 = ps->cor1;
const float var0 = ps->var0, var1 = ps->var1;
const float e0 = *coef - ps->x_est;
const float e1 = e0 - k1 * r0;
if (set)
*coef = e0;
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);
/* Prediction for next frame */
ps->k1 = ps->var0 > 1 ? ps->cor0 * flt16_even(a / ps->var0) : 0;
k2 = ps->var1 > 1 ? ps->cor1 * flt16_even(a / ps->var1) : 0;
*rcoef = ps->x_est = flt16_round(ps->k1*ps->r0 + k2*ps->r1);
}
static inline void reset_predict_state(PredictorState *ps)
{
ps->r0 = 0.0f;
ps->r1 = 0.0f;
ps->k1 = 0.0f;
ps->cor0 = 0.0f;
ps->cor1 = 0.0f;
ps->var0 = 1.0f;
ps->var1 = 1.0f;
ps->x_est = 0.0f;
}
static inline void reset_all_predictors(PredictorState *ps)
{
int i;
for (i = 0; i < MAX_PREDICTORS; i++)
reset_predict_state(&ps[i]);
}
static inline void reset_predictor_group(SingleChannelElement *sce, int group_num)
{
int i;
PredictorState *ps = sce->predictor_state;
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;
const int pmax = FFMIN(sce->ics.max_sfb, ff_aac_pred_sfb_max[s->samplerate_index]);
if (sce->ics.window_sequence[0] != EIGHT_SHORT_SEQUENCE) {
for (sfb = 0; sfb < pmax; 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]);
}
}
if (sce->ics.predictor_reset_group) {
reset_predictor_group(sce, sce->ics.predictor_reset_group);
}
} else {
reset_all_predictors(sce->predictor_state);
}
}
/* If inc = 0 you can check if this returns 0 to see if you can reset freely */
static inline int update_counters(IndividualChannelStream *ics, int inc)
{
int i;
for (i = 1; i < 31; i++) {
ics->predictor_reset_count[i] += inc;
if (ics->predictor_reset_count[i] > PRED_RESET_FRAME_MIN)
return i; /* Reset this immediately */
}
return 0;
}
void ff_aac_adjust_common_prediction(AACEncContext *s, ChannelElement *cpe)
{
int start, w, w2, g, i, count = 0;
SingleChannelElement *sce0 = &cpe->ch[0];
SingleChannelElement *sce1 = &cpe->ch[1];
const int pmax0 = FFMIN(sce0->ics.max_sfb, ff_aac_pred_sfb_max[s->samplerate_index]);
const int pmax1 = FFMIN(sce1->ics.max_sfb, ff_aac_pred_sfb_max[s->samplerate_index]);
const int pmax = FFMIN(pmax0, pmax1);
if (!cpe->common_window ||
sce0->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE ||
sce1->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE)
return;
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;
int sum = sce0->ics.prediction_used[sfb] + sce1->ics.prediction_used[sfb];
float ener0 = 0.0f, ener1 = 0.0f, ener01 = 0.0f;
struct AACISError ph_err1, ph_err2, *erf;
if (sfb < PRED_SFB_START || sfb > pmax || sum != 2) {
RESTORE_PRED(sce0, sfb);
RESTORE_PRED(sce1, sfb);
start += sce0->ics.swb_sizes[g];
continue;
}
for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
float coef0 = sce0->pcoeffs[start+(w+w2)*128+i];
float coef1 = sce1->pcoeffs[start+(w+w2)*128+i];
ener0 += coef0*coef0;
ener1 += coef1*coef1;
ener01 += (coef0 + coef1)*(coef0 + coef1);
}
}
ph_err1 = ff_aac_is_encoding_err(s, cpe, start, w, g,
ener0, ener1, ener01, 1, -1);
ph_err2 = ff_aac_is_encoding_err(s, cpe, start, w, g,
ener0, ener1, ener01, 1, +1);
erf = ph_err1.error < ph_err2.error ? &ph_err1 : &ph_err2;
if (erf->pass) {
sce0->ics.prediction_used[sfb] = 1;
sce1->ics.prediction_used[sfb] = 1;
count++;
} else {
RESTORE_PRED(sce0, sfb);
RESTORE_PRED(sce1, sfb);
}
start += sce0->ics.swb_sizes[g];
}
}
sce1->ics.predictor_present = sce0->ics.predictor_present = !!count;
}
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;
/* Update the counters and immediately update any frame behind schedule */
if ((ics->predictor_reset_group = update_counters(&sce->ics, 1)))
return;
for (i = 1; i < 31; i++) {
/* Count-based */
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 (max_frame > PRED_RESET_MIN) {
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, cost_coeffs = 0, cost_pred = 0;
const int pmax = FFMIN(sce->ics.max_sfb, ff_aac_pred_sfb_max[s->samplerate_index]);
float *O34 = &s->scoefs[128*0], *P34 = &s->scoefs[128*1];
float *SENT = &s->scoefs[128*2], *S34 = &s->scoefs[128*3];
float *QERR = &s->scoefs[128*4];
if (sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE) {
sce->ics.predictor_present = 0;
return;
}
if (!sce->ics.predictor_initialized) {
reset_all_predictors(sce->predictor_state);
sce->ics.predictor_initialized = 1;
memcpy(sce->prcoeffs, sce->coeffs, 1024*sizeof(float));
for (i = 1; i < 31; i++)
sce->ics.predictor_reset_count[i] = i;
}
update_pred_resets(sce);
memcpy(sce->band_alt, sce->band_type, sizeof(sce->band_type));
for (sfb = PRED_SFB_START; sfb < pmax; sfb++) {
int cost1, cost2, cb_p;
float dist1, dist2, dist_spec_err = 0.0f;
const int cb_n = sce->band_type[sfb];
const int start_coef = sce->ics.swb_offset[sfb];
const int num_coeffs = sce->ics.swb_offset[sfb + 1] - start_coef;
const FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[sfb];
if (start_coef + num_coeffs > MAX_PREDICTORS)
continue;
/* Normal coefficients */
abs_pow34_v(O34, &sce->coeffs[start_coef], num_coeffs);
dist1 = quantize_and_encode_band_cost(s, NULL, &sce->coeffs[start_coef], NULL,
O34, num_coeffs, sce->sf_idx[sfb],
cb_n, s->lambda / band->threshold, INFINITY, &cost1, 0);
cost_coeffs += cost1;
/* Encoded coefficients - needed for #bits, band type and quant. error */
for (i = 0; i < num_coeffs; i++)
SENT[i] = sce->coeffs[start_coef + i] - sce->prcoeffs[start_coef + i];
abs_pow34_v(S34, SENT, num_coeffs);
if (cb_n < RESERVED_BT)
cb_p = find_min_book(find_max_val(1, num_coeffs, S34), sce->sf_idx[sfb]);
else
cb_p = cb_n;
quantize_and_encode_band_cost(s, NULL, SENT, QERR, S34, num_coeffs,
sce->sf_idx[sfb], cb_p, s->lambda / band->threshold, INFINITY,
&cost2, 0);
/* Reconstructed coefficients - needed for distortion measurements */
for (i = 0; i < num_coeffs; i++)
sce->prcoeffs[start_coef + i] += QERR[i] != 0.0f ? (sce->prcoeffs[start_coef + i] - QERR[i]) : 0.0f;
abs_pow34_v(P34, &sce->prcoeffs[start_coef], num_coeffs);
if (cb_n < RESERVED_BT)
cb_p = find_min_book(find_max_val(1, num_coeffs, P34), sce->sf_idx[sfb]);
else
cb_p = cb_n;
dist2 = quantize_and_encode_band_cost(s, NULL, &sce->prcoeffs[start_coef], NULL,
P34, num_coeffs, sce->sf_idx[sfb],
cb_p, s->lambda / band->threshold, INFINITY, NULL, 0);
for (i = 0; i < num_coeffs; i++)
dist_spec_err += (O34[i] - P34[i])*(O34[i] - P34[i]);
dist_spec_err *= s->lambda / band->threshold;
dist2 += dist_spec_err;
if (dist2 <= dist1 && cb_p <= cb_n) {
cost_pred += cost2;
sce->ics.prediction_used[sfb] = 1;
sce->band_alt[sfb] = cb_n;
sce->band_type[sfb] = cb_p;
count++;
} else {
cost_pred += cost1;
sce->band_alt[sfb] = cb_p;
}
}
if (count && cost_coeffs < cost_pred) {
count = 0;
for (sfb = PRED_SFB_START; sfb < pmax; sfb++)
RESTORE_PRED(sce, sfb);
memset(&sce->ics.prediction_used, 0, sizeof(sce->ics.prediction_used));
}
sce->ics.predictor_present = !!count;
}
/**
* Encoder predictors data.
*/
void ff_aac_encode_main_pred(AACEncContext *s, SingleChannelElement *sce)
{
int sfb;
IndividualChannelStream *ics = &sce->ics;
const int pmax = FFMIN(ics->max_sfb, ff_aac_pred_sfb_max[s->samplerate_index]);
if (!ics->predictor_present)
return;
put_bits(&s->pb, 1, !!ics->predictor_reset_group);
if (ics->predictor_reset_group)
put_bits(&s->pb, 5, ics->predictor_reset_group);
for (sfb = 0; sfb < pmax; sfb++)
put_bits(&s->pb, 1, ics->prediction_used[sfb]);
}
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