libavcodec/aacenc_pred.c - nest-android-app/ffmpeg - Git at Google

 /*
  * 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-type prediction
  * @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_pred(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->zeroes[sfb] ? 0 : sce->band_type[sfb];
         const int cb_min = sce->zeroes[sfb] ? 0 : 1;
         const int cb_max = sce->zeroes[sfb] ? 0 : RESERVED_BT;
         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 ||
             (s->cur_channel && sce->band_type[sfb] >= INTENSITY_BT2) ||
             sce->band_type[sfb] == NOISE_BT)
             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, NULL, 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 = av_clip(find_min_book(find_max_val(1, num_coeffs, S34), sce->sf_idx[sfb]), cb_min, cb_max);
         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, NULL, 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 = av_clip(find_min_book(find_max_val(1, num_coeffs, P34), sce->sf_idx[sfb]), cb_min, cb_max);
         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, 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 (s->profile != FF_PROFILE_AAC_MAIN ||
         !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]);
 }
	/*
	* 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-type prediction
	* @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->k1ps->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_pred(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[1280], P34 = &s->scoefs[1281];
	float SENT = &s->scoefs[1282], S34 = &s->scoefs[1283];
	float QERR = &s->scoefs[1284];

	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->zeroes[sfb] ? 0 : sce->band_type[sfb];
	const int cb_min = sce->zeroes[sfb] ? 0 : 1;
	const int cb_max = sce->zeroes[sfb] ? 0 : RESERVED_BT;
	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 \|\|
	(s->cur_channel && sce->band_type[sfb] >= INTENSITY_BT2) \|\|
	sce->band_type[sfb] == NOISE_BT)
	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, NULL, 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 = av_clip(find_min_book(find_max_val(1, num_coeffs, S34), sce->sf_idx[sfb]), cb_min, cb_max);
	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, NULL, 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 = av_clip(find_min_book(find_max_val(1, num_coeffs, P34), sce->sf_idx[sfb]), cb_min, cb_max);
	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, 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 (s->profile != FF_PROFILE_AAC_MAIN \|\|
	!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]);
	}