mirror of
https://github.com/ZLMediaKit/ZLMediaKit.git
synced 2024-11-27 05:38:31 +08:00
272 lines
7.0 KiB
C++
272 lines
7.0 KiB
C++
/*
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** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
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** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
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**
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** This program is free software; you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation; either version 2 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program; if not, write to the Free Software
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** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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**
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** Any non-GPL usage of this software or parts of this software is strictly
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** forbidden.
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**
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** The "appropriate copyright message" mentioned in section 2c of the GPLv2
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** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
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**
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** Commercial non-GPL licensing of this software is possible.
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** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
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**
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** $Id: ic_predict.c,v 1.28 2007/11/01 12:33:31 menno Exp $
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**/
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#include "common.h"
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#include "structs.h"
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#ifdef MAIN_DEC
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#include "syntax.h"
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#include "ic_predict.h"
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#include "pns.h"
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static void flt_round(float32_t *pf)
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{
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int32_t flg;
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uint32_t tmp, tmp1, tmp2;
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tmp = *(uint32_t*)pf;
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flg = tmp & (uint32_t)0x00008000;
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tmp &= (uint32_t)0xffff0000;
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tmp1 = tmp;
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/* round 1/2 lsb toward infinity */
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if (flg)
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{
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tmp &= (uint32_t)0xff800000; /* extract exponent and sign */
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tmp |= (uint32_t)0x00010000; /* insert 1 lsb */
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tmp2 = tmp; /* add 1 lsb and elided one */
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tmp &= (uint32_t)0xff800000; /* extract exponent and sign */
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*pf = *(float32_t*)&tmp1 + *(float32_t*)&tmp2 - *(float32_t*)&tmp;
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} else {
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*pf = *(float32_t*)&tmp;
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}
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}
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static int16_t quant_pred(float32_t x)
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{
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int16_t q;
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uint32_t *tmp = (uint32_t*)&x;
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q = (int16_t)(*tmp>>16);
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return q;
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}
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static float32_t inv_quant_pred(int16_t q)
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{
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float32_t x;
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uint32_t *tmp = (uint32_t*)&x;
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*tmp = ((uint32_t)q)<<16;
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return x;
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}
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static void ic_predict(pred_state *state, real_t input, real_t *output, uint8_t pred)
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{
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uint16_t tmp;
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int16_t i, j;
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real_t dr1;
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float32_t predictedvalue;
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real_t e0, e1;
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real_t k1, k2;
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real_t r[2];
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real_t COR[2];
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real_t VAR[2];
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r[0] = inv_quant_pred(state->r[0]);
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r[1] = inv_quant_pred(state->r[1]);
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COR[0] = inv_quant_pred(state->COR[0]);
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COR[1] = inv_quant_pred(state->COR[1]);
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VAR[0] = inv_quant_pred(state->VAR[0]);
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VAR[1] = inv_quant_pred(state->VAR[1]);
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#if 1
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tmp = state->VAR[0];
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j = (tmp >> 7);
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i = tmp & 0x7f;
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if (j >= 128)
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{
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j -= 128;
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k1 = COR[0] * exp_table[j] * mnt_table[i];
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} else {
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k1 = REAL_CONST(0);
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}
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#else
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{
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#define B 0.953125
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real_t c = COR[0];
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real_t v = VAR[0];
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float32_t tmp;
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if (c == 0 || v <= 1)
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{
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k1 = 0;
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} else {
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tmp = B / v;
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flt_round(&tmp);
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k1 = c * tmp;
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}
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}
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#endif
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if (pred)
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{
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#if 1
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tmp = state->VAR[1];
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j = (tmp >> 7);
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i = tmp & 0x7f;
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if (j >= 128)
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{
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j -= 128;
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k2 = COR[1] * exp_table[j] * mnt_table[i];
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} else {
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k2 = REAL_CONST(0);
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}
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#else
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#define B 0.953125
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real_t c = COR[1];
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real_t v = VAR[1];
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float32_t tmp;
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if (c == 0 || v <= 1)
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{
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k2 = 0;
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} else {
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tmp = B / v;
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flt_round(&tmp);
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k2 = c * tmp;
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}
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#endif
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predictedvalue = k1*r[0] + k2*r[1];
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flt_round(&predictedvalue);
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*output = input + predictedvalue;
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}
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/* calculate new state data */
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e0 = *output;
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e1 = e0 - k1*r[0];
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dr1 = k1*e0;
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VAR[0] = ALPHA*VAR[0] + 0.5f * (r[0]*r[0] + e0*e0);
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COR[0] = ALPHA*COR[0] + r[0]*e0;
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VAR[1] = ALPHA*VAR[1] + 0.5f * (r[1]*r[1] + e1*e1);
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COR[1] = ALPHA*COR[1] + r[1]*e1;
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r[1] = A * (r[0]-dr1);
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r[0] = A * e0;
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state->r[0] = quant_pred(r[0]);
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state->r[1] = quant_pred(r[1]);
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state->COR[0] = quant_pred(COR[0]);
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state->COR[1] = quant_pred(COR[1]);
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state->VAR[0] = quant_pred(VAR[0]);
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state->VAR[1] = quant_pred(VAR[1]);
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}
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static void reset_pred_state(pred_state *state)
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{
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state->r[0] = 0;
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state->r[1] = 0;
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state->COR[0] = 0;
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state->COR[1] = 0;
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state->VAR[0] = 0x3F80;
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state->VAR[1] = 0x3F80;
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}
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void pns_reset_pred_state(ic_stream *ics, pred_state *state)
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{
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uint8_t sfb, g, b;
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uint16_t i, offs, offs2;
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/* prediction only for long blocks */
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if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
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return;
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for (g = 0; g < ics->num_window_groups; g++)
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{
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for (b = 0; b < ics->window_group_length[g]; b++)
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{
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for (sfb = 0; sfb < ics->max_sfb; sfb++)
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{
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if (is_noise(ics, g, sfb))
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{
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offs = ics->swb_offset[sfb];
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offs2 = min(ics->swb_offset[sfb+1], ics->swb_offset_max);
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for (i = offs; i < offs2; i++)
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reset_pred_state(&state[i]);
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}
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}
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}
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}
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}
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void reset_all_predictors(pred_state *state, uint16_t frame_len)
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{
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uint16_t i;
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for (i = 0; i < frame_len; i++)
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reset_pred_state(&state[i]);
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}
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/* intra channel prediction */
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void ic_prediction(ic_stream *ics, real_t *spec, pred_state *state,
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uint16_t frame_len, uint8_t sf_index)
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{
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uint8_t sfb;
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uint16_t bin;
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if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
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{
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reset_all_predictors(state, frame_len);
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} else {
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for (sfb = 0; sfb < max_pred_sfb(sf_index); sfb++)
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{
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uint16_t low = ics->swb_offset[sfb];
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uint16_t high = min(ics->swb_offset[sfb+1], ics->swb_offset_max);
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for (bin = low; bin < high; bin++)
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{
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ic_predict(&state[bin], spec[bin], &spec[bin],
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(ics->predictor_data_present && ics->pred.prediction_used[sfb]));
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}
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}
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if (ics->predictor_data_present)
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{
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if (ics->pred.predictor_reset)
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{
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for (bin = ics->pred.predictor_reset_group_number - 1;
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bin < frame_len; bin += 30)
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{
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reset_pred_state(&state[bin]);
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}
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}
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}
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}
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}
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#endif
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