201 lines
5.7 KiB
C++
201 lines
5.7 KiB
C++
/*
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* Project 25 IMBE Encoder/Decoder Fixed-Point implementation
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* Developed by Pavel Yazev E-mail: pyazev@gmail.com
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* Version 1.0 (c) Copyright 2009
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*
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* This is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* The software is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the 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; see the file COPYING. If not, write to the Free
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* Software Foundation, Inc., 51 Franklin Street, Boston, MA
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* 02110-1301, USA.
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*/
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#include "typedef.h"
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#include "globals.h"
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#include "basic_op.h"
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#include "imbe.h"
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#include "tbls.h"
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#include "qnt_sub.h"
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#include "sa_decode.h"
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#include "aux_sub.h"
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#include "dsp_sub.h"
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#include "math_sub.h"
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#include "encode.h"
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#include "imbe_vocoder.h"
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Initialization of Spectral Amplitude Decoder
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//
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//
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// INPUT:
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// None
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//
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// OUTPUT:
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// None
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//
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// RETURN:
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// None
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//
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//-----------------------------------------------------------------------------
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void imbe_vocoder::sa_decode_init(void)
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{
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num_harms_prev1 = 30;
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v_zap((Word16 *)sa_prev1, 2 * (NUM_HARMS_MAX + 2));
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}
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Perform Spectral Amplitude Decoding
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//
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//
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// INPUT:
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// IMBE_PARAM *imbe_param - pointer to IMBE_PARAM structure with
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// valid num_harms and b_vec items
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//
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// OUTPUT:
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// None
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//
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// RETURN:
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// Decoded Spectral Amplitudes
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//
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//-----------------------------------------------------------------------------
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void imbe_vocoder::sa_decode(IMBE_PARAM *imbe_param)
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{
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Word16 gain_vec[6], gain_r[6];
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UWord16 index, index_1, num_harms;
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Word16 *gss_ptr, *ba_ptr, i, j, *t_vec_ptr, *b_vec_ptr;
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Word16 t_vec[NUM_HARMS_MAX], c_vec[MAX_BLOCK_LEN];
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Word32 lmprbl_item;
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Word16 bl_len, step_size, num_bits, tmp, ro_coef, si_coef, tmp1;
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UWord32 k_coef, k_acc;
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Word32 sum, tmp_word32, sa_tmp[NUM_HARMS_MAX];
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Word16 *sa;
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num_harms = imbe_param->num_harms;
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index = num_harms - NUM_HARMS_MIN;
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ba_ptr = imbe_param->bit_alloc;
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b_vec_ptr = &imbe_param->b_vec[2];
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sa = imbe_param->sa;
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// Decoding the Gain Vector. gain_vec has signed Q5.11 format
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gss_ptr = (Word16 *)&gain_step_size_tbl[index * 5];
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gain_vec[0] = gain_qnt_tbl[*b_vec_ptr++];
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for(i = 1; i < 6; i++)
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gain_vec[i] = extract_l(L_shr(deqnt_by_step(*b_vec_ptr++, *gss_ptr++, *ba_ptr++), 5));
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idct(gain_vec, NUM_PRED_RES_BLKS, NUM_PRED_RES_BLKS, gain_r);
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lmprbl_item = lmprbl_tbl[index];
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v_zap(t_vec, NUM_HARMS_MAX);
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// Decoding the Higher Order DCT Coefficients
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t_vec_ptr = t_vec;
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for(i = 0; i < NUM_PRED_RES_BLKS; i++)
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{
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bl_len = (lmprbl_item >> 28) & 0xF; lmprbl_item <<= 4;
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v_zap(c_vec, MAX_BLOCK_LEN);
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c_vec[0] = gain_r[i];
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for(j = 1; j < bl_len; j++)
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{
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num_bits = *ba_ptr++;
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if(num_bits)
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{
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step_size = extract_h(((Word32)hi_ord_std_tbl[j - 1] * hi_ord_step_size_tbl[num_bits - 1]) << 1);
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c_vec[j] = extract_l(L_shr(deqnt_by_step(*b_vec_ptr, step_size, num_bits), 5));
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}
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else
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c_vec[j] = 0;
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b_vec_ptr++;
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}
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idct(c_vec, bl_len, bl_len, t_vec_ptr);
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t_vec_ptr += bl_len;
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}
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// Calculate num_harms_prev/num_harms. Result save in unsigned format Q8.24
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if(num_harms == num_harms_prev1)
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k_coef = (Word32)CNST_ONE_Q8_24;
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else if(num_harms > num_harms_prev1)
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k_coef = (Word32)div_s(num_harms_prev1 << 9, num_harms << 9) << 9;
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else
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{
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// imbe_param->num_harms < num_harms_prev1
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k_coef = 0;
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tmp = num_harms_prev1;
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while(tmp > num_harms)
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{
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tmp -= num_harms;
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k_coef += (Word32)CNST_ONE_Q8_24;
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}
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k_coef += (Word32)div_s(tmp << 9, num_harms << 9) << 9;
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}
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if(num_harms <= 15)
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ro_coef = CNST_0_4_Q1_15;
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else if(num_harms <= 24)
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ro_coef = num_harms * CNST_0_03_Q1_15 - CNST_0_05_Q1_15;
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else
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ro_coef = CNST_0_7_Q1_15;
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k_acc = k_coef;
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sum = 0;
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for(i = num_harms_prev1 + 1; i < NUM_HARMS_MAX + 2; i++)
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sa_prev1[i] = sa_prev1[num_harms_prev1];
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for(i = 0; i < num_harms; i++)
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{
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index = (UWord16)(k_acc >> 24); // Get integer part
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si_coef = (Word16)((k_acc - ((UWord32)index << 24)) >> 9); // Get fractional part
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if(si_coef == 0)
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{
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tmp_word32 = L_mpy_ls(sa_prev1[index], ro_coef); // sa_prev1 here is in Q10.22 format
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sa_tmp[i] = L_add(L_shr(L_deposit_h(t_vec[i]), 5), tmp_word32); // Convert t_vec to Q10.22 and add ...
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sum = L_add(sum, sa_prev1[index]); // sum in Q10.22 format
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}
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else
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{
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index_1 = index + 1;
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tmp_word32 = L_mpy_ls(sa_prev1[index], sub(0x7FFF, si_coef));
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sum = L_add(sum, tmp_word32);
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sa_tmp[i] = L_add(L_shr(L_deposit_h(t_vec[i]), 5), L_mpy_ls(tmp_word32, ro_coef));
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tmp_word32 = L_mpy_ls(sa_prev1[index_1], si_coef);
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sum = L_add(sum, tmp_word32);
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sa_tmp[i] = L_add(sa_tmp[i], L_mpy_ls(tmp_word32, ro_coef));
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}
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k_acc += k_coef;
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}
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imbe_param->div_one_by_num_harm_sh = tmp = norm_s(num_harms);
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imbe_param->div_one_by_num_harm = tmp1 = div_s(0x4000, num_harms << tmp); // calculate 1/num_harms with scaling for better pricision
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// save result to use late
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sum = L_shr(L_mpy_ls(L_mpy_ls(sum, ro_coef), tmp1), (14 - tmp));
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for(i = 1; i <= num_harms; i++)
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{
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sa_prev1[i] = L_sub(sa_tmp[i - 1], sum);
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sa[i - 1] = Pow2(sa_prev1[i]);
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}
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num_harms_prev1 = num_harms;
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}
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