dec_acelp.c
上传用户:zhongxx05
上传日期:2007-06-06
资源大小:33641k
文件大小:15k
- /*
- *===================================================================
- * 3GPP AMR Wideband Floating-point Speech Codec
- *===================================================================
- */
- #include "hlxclib/memory.h"
- #include "typedef.h"
- #include "dec_util.h"
- #define L_SUBFR 64 /* Subframe size */
- #define PRED_ORDER 4
- #define MEAN_ENER 30 /* average innovation energy */
- extern const Word16 D_ROM_ph_imp_low[];
- extern const Word16 D_ROM_ph_imp_mid[];
- /*
- * D_ACELP_add_pulse
- *
- * Parameters:
- * pos I: position of pulse
- * nb_pulse I: number of pulses
- * track I: track
- * code O: fixed codebook
- *
- * Function:
- * Add pulses to fixed codebook
- *
- * Returns:
- * void
- */
- static void D_ACELP_add_pulse(Word32 pos[], Word32 nb_pulse,
- Word32 track, Word16 code[])
- {
- Word32 i, k;
- for(k = 0; k < nb_pulse; k++)
- {
- /* i = ((pos[k] & (16-1))*NB_TRACK) + track; */
- i = ((pos[k] & (16 - 1)) << 2) + track;
- if((pos[k] & 16) == 0)
- {
- code[i] = (Word16)(code[i] + 512);
- }
- else
- {
- code[i] = (Word16)(code[i] - 512);
- }
- }
- return;
- }
- /*
- * D_ACELP_decode_1p_N1
- *
- * Parameters:
- * index I: pulse index
- * N I: number of bits for position
- * offset I: offset
- * pos O: position of the pulse
- *
- * Function:
- * Decode 1 pulse with N+1 bits
- *
- * Returns:
- * void
- */
- static void D_ACELP_decode_1p_N1(Word32 index, Word32 N,
- Word32 offset, Word32 pos[])
- {
- Word32 i, pos1, mask;
- mask = ((1 << N) - 1);
- /*
- * Decode 1 pulse with N+1 bits
- */
- pos1 = ((index & mask) + offset);
- i = ((index >> N) & 1);
- if(i == 1)
- {
- pos1 += 16;
- }
- pos[0] = pos1;
- return;
- }
- /*
- * D_ACELP_decode_2p_2N1
- *
- * Parameters:
- * index I: pulse index
- * N I: number of bits for position
- * offset I: offset
- * pos O: position of the pulse
- *
- * Function:
- * Decode 2 pulses with 2*N+1 bits
- *
- * Returns:
- * void
- */
- static void D_ACELP_decode_2p_2N1(Word32 index, Word32 N,
- Word32 offset, Word32 pos[])
- {
- Word32 i, pos1, pos2;
- Word32 mask;
- mask = ((1 << N) - 1);
- /*
- * Decode 2 pulses with 2*N+1 bits
- */
- pos1 = (((index >> N) & mask) + offset);
- i = (index >> (2 * N)) & 1;
- pos2 = ((index & mask) + offset);
- if((pos2 - pos1) < 0)
- {
- if(i == 1)
- {
- pos1 += 16;
- }
- else
- {
- pos2 += 16;
- }
- }
- else
- {
- if(i == 1)
- {
- pos1 += 16;
- pos2 += 16;
- }
- }
- pos[0] = pos1;
- pos[1] = pos2;
- return;
- }
- /*
- * D_ACELP_decode_3p_3N1
- *
- * Parameters:
- * index I: pulse index
- * N I: number of bits for position
- * offset I: offset
- * pos O: position of the pulse
- *
- * Function:
- * Decode 3 pulses with 3*N+1 bits
- *
- * Returns:
- * void
- */
- static void D_ACELP_decode_3p_3N1(Word32 index, Word32 N,
- Word32 offset, Word32 pos[])
- {
- Word32 j, mask, idx;
- /*
- * Decode 3 pulses with 3*N+1 bits
- */
- mask = ((1 << ((2 * N) - 1)) - 1);
- idx = index & mask;
- j = offset;
- if(((index >> ((2 * N) - 1)) & 1) == 1)
- {
- j += (1 << (N - 1));
- }
- D_ACELP_decode_2p_2N1(idx, N - 1, j, pos);
- mask = ((1 << (N + 1)) - 1);
- idx = (index >> (2 * N)) & mask;
- D_ACELP_decode_1p_N1(idx, N, offset, pos + 2);
- return;
- }
- /*
- * D_ACELP_decode_4p_4N1
- *
- * Parameters:
- * index I: pulse index
- * N I: number of bits for position
- * offset I: offset
- * pos O: position of the pulse
- *
- * Function:
- * Decode 4 pulses with 4*N+1 bits
- *
- * Returns:
- * void
- */
- static void D_ACELP_decode_4p_4N1(Word32 index, Word32 N,
- Word32 offset, Word32 pos[])
- {
- Word32 j, mask, idx;
- /*
- * Decode 4 pulses with 4*N+1 bits
- */
- mask = ((1 << ((2 * N) - 1)) - 1);
- idx = index & mask;
- j = offset;
- if(((index >> ((2 * N) - 1)) & 1) == 1)
- {
- j += (1 << (N - 1));
- }
- D_ACELP_decode_2p_2N1(idx, N - 1, j, pos);
- mask = ((1 << ((2 * N) + 1)) - 1);
- idx = (index >> (2 * N)) & mask;
- D_ACELP_decode_2p_2N1(idx, N, offset, pos + 2);
- return;
- }
- /*
- * D_ACELP_decode_4p_4N
- *
- * Parameters:
- * index I: pulse index
- * N I: number of bits for position
- * offset I: offset
- * pos O: position of the pulse
- *
- * Function:
- * Decode 4 pulses with 4*N bits
- *
- * Returns:
- * void
- */
- static void D_ACELP_decode_4p_4N(Word32 index, Word32 N,
- Word32 offset, Word32 pos[])
- {
- Word32 j, n_1;
- /*
- * Decode 4 pulses with 4*N bits
- */
- n_1 = N - 1;
- j = offset + (1 << n_1);
- switch((index >> ((4 * N) - 2)) & 3)
- {
- case 0:
- if(((index >> ((4 * n_1) + 1)) & 1) == 0)
- {
- D_ACELP_decode_4p_4N1(index, n_1, offset, pos);
- }
- else
- {
- D_ACELP_decode_4p_4N1(index, n_1, j, pos);
- }
- break;
- case 1:
- D_ACELP_decode_1p_N1((index >> ((3 * n_1) + 1)), n_1, offset, pos);
- D_ACELP_decode_3p_3N1(index, n_1, j, pos + 1);
- break;
- case 2:
- D_ACELP_decode_2p_2N1((index >> ((2 * n_1) + 1)), n_1, offset, pos);
- D_ACELP_decode_2p_2N1(index, n_1, j, pos + 2);
- break;
- case 3:
- D_ACELP_decode_3p_3N1((index >> (n_1 + 1)), n_1, offset, pos);
- D_ACELP_decode_1p_N1(index, n_1, j, pos + 3);
- break;
- }
- return;
- }
- /*
- * D_ACELP_decode_5p_5N
- *
- * Parameters:
- * index I: pulse index
- * N I: number of bits for position
- * offset I: offset
- * pos O: position of the pulse
- *
- * Function:
- * Decode 5 pulses with 5*N bits
- *
- * Returns:
- * void
- */
- static void D_ACELP_decode_5p_5N(Word32 index, Word32 N,
- Word32 offset, Word32 pos[])
- {
- Word32 j, n_1;
- Word32 idx;
- /*
- * Decode 5 pulses with 5*N bits
- */
- n_1 = N - 1;
- j = offset + (1 << n_1);
- idx = (index >> ((2 * N) + 1));
- if(((index >> ((5 * N) - 1)) & 1) == 0)
- {
- D_ACELP_decode_3p_3N1(idx, n_1, offset, pos);
- D_ACELP_decode_2p_2N1(index, N, offset, pos + 3);
- }
- else
- {
- D_ACELP_decode_3p_3N1(idx, n_1, j, pos);
- D_ACELP_decode_2p_2N1(index, N, offset, pos + 3);
- }
- return;
- }
- /*
- * D_ACELP_decode_6p_6N_2
- *
- * Parameters:
- * index I: pulse index
- * N I: number of bits for position
- * offset I: offset
- * pos O: position of the pulse
- *
- * Function:
- * Decode 6 pulses with 6*N-2 bits
- *
- * Returns:
- * void
- */
- static void D_ACELP_decode_6p_6N_2(Word32 index, Word32 N,
- Word32 offset, Word32 pos[])
- {
- Word32 j, n_1, offsetA, offsetB;
- n_1 = N - 1;
- j = offset + (1 << n_1);
- offsetA = offsetB = j;
- if(((index >> ((6 * N) - 5)) & 1) == 0)
- {
- offsetA = offset;
- }
- else
- {
- offsetB = offset;
- }
- switch((index >> ((6 * N) - 4)) & 3)
- {
- case 0:
- D_ACELP_decode_5p_5N(index >> N, n_1, offsetA, pos);
- D_ACELP_decode_1p_N1(index, n_1, offsetA, pos + 5);
- break;
- case 1:
- D_ACELP_decode_5p_5N(index >> N, n_1, offsetA, pos);
- D_ACELP_decode_1p_N1(index, n_1, offsetB, pos + 5);
- break;
- case 2:
- D_ACELP_decode_4p_4N(index >> ((2 * n_1) + 1), n_1, offsetA, pos);
- D_ACELP_decode_2p_2N1(index, n_1, offsetB, pos + 4);
- break;
- case 3:
- D_ACELP_decode_3p_3N1(index >> ((3 * n_1) + 1), n_1, offset, pos);
- D_ACELP_decode_3p_3N1(index, n_1, j, pos + 3);
- break;
- }
- return;
- }
- /*
- * D_ACELP_decode_2t
- *
- * Parameters:
- * index I: 12 bits index
- * code O: (Q9) algebraic (fixed) codebook excitation
- *
- * Function:
- * 12 bits algebraic codebook decoder.
- * 2 tracks x 32 positions per track = 64 samples.
- *
- * 12 bits --> 2 pulses in a frame of 64 samples.
- *
- * All pulses can have two (2) possible amplitudes: +1 or -1.
- * Each pulse can have 32 possible positions.
- *
- * codevector length 64
- * number of track 2
- * number of position 32
- *
- * Returns:
- * void
- */
- void D_ACELP_decode_2t(Word16 index, Word16 code[])
- {
- Word32 i0, i1;
- memset(code, 0, 64 * sizeof(Word16));
- /* decode the positions and signs of pulses and build the codeword */
- i0 = (index >> 5) & 0x0000003E;
- i1 = ((index & 0x0000001F) << 1) + 1;
- if(((index >> 6) & 32) == 0)
- {
- code[i0] = 512;
- }
- else
- {
- code[i0] = -512;
- }
- if((index & 32) == 0)
- {
- code[i1] = 512;
- }
- else
- {
- code[i1] = -512;
- }
- return;
- }
- /*
- * D_ACELP_decode_4t
- *
- * Parameters:
- * index I: index
- * mode I: speech mode
- * code I: (Q9) algebraic (fixed) codebook excitation
- *
- * Function:
- * 20, 36, 44, 52, 64, 72, 88 bits algebraic codebook.
- * 4 tracks x 16 positions per track = 64 samples.
- *
- * 20 bits 5+5+5+5 --> 4 pulses in a frame of 64 samples.
- * 36 bits 9+9+9+9 --> 8 pulses in a frame of 64 samples.
- * 44 bits 13+9+13+9 --> 10 pulses in a frame of 64 samples.
- * 52 bits 13+13+13+13 --> 12 pulses in a frame of 64 samples.
- * 64 bits 2+2+2+2+14+14+14+14 --> 16 pulses in a frame of 64 samples.
- * 72 bits 10+2+10+2+10+14+10+14 --> 18 pulses in a frame of 64 samples.
- * 88 bits 11+11+11+11+11+11+11+11 --> 24 pulses in a frame of 64 samples.
- *
- * All pulses can have two (2) possible amplitudes: +1 or -1.
- * Each pulse can sixteen (16) possible positions.
- *
- * codevector length 64
- * number of track 4
- * number of position 16
- *
- * Returns:
- * void
- */
- void D_ACELP_decode_4t(Word16 index[], Word16 nbbits, Word16 code[])
- {
- Word32 k, L_index, pos[6];
- memset(code, 0, 64 * sizeof(Word16));
- /* decode the positions and signs of pulses and build the codeword */
- if(nbbits == 20)
- {
- for(k = 0; k < 4; k++)
- {
- L_index = index[k];
- D_ACELP_decode_1p_N1(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 1, k, code);
- }
- }
- else if(nbbits == 36)
- {
- for(k = 0; k < 4; k++)
- {
- L_index = index[k];
- D_ACELP_decode_2p_2N1(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 2, k, code);
- }
- }
- else if(nbbits == 44)
- {
- for(k = 0; k < 4 - 2; k++)
- {
- L_index = index[k];
- D_ACELP_decode_3p_3N1(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 3, k, code);
- }
- for(k = 2; k < 4; k++)
- {
- L_index = index[k];
- D_ACELP_decode_2p_2N1(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 2, k, code);
- }
- }
- else if(nbbits == 52)
- {
- for(k = 0; k < 4; k++)
- {
- L_index = index[k];
- D_ACELP_decode_3p_3N1(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 3, k, code);
- }
- }
- else if(nbbits == 64)
- {
- for(k = 0; k < 4; k++)
- {
- L_index = ((index[k] << 14) + index[k + 4]);
- D_ACELP_decode_4p_4N(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 4, k, code);
- }
- }
- else if(nbbits == 72)
- {
- for(k = 0; k < 4 - 2; k++)
- {
- L_index = ((index[k] << 10) + index[k + 4]);
- D_ACELP_decode_5p_5N(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 5, k, code);
- }
- for(k = 2; k < 4; k++)
- {
- L_index = ((index[k] << 14) + index[k + 4]);
- D_ACELP_decode_4p_4N(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 4, k, code);
- }
- }
- else if(nbbits == 88)
- {
- for(k = 0; k < 4; k++)
- {
- L_index = ((index[k] << 11) + index[k + 4]);
- D_ACELP_decode_6p_6N_2(L_index, 4, 0, pos);
- D_ACELP_add_pulse(pos, 6, k, code);
- }
- }
- return;
- }
- /*
- * D_ACELP_phase_dispersion
- *
- * Parameters:
- * gain_code I: (Q0) gain of code
- * gain_pit I: (Q14) gain of pitch
- * code I/O: code vector
- * mode I: level, 0=hi, 1=lo, 2=off
- * disp_mem I/O: static memory (size = 8)
- *
- * Function:
- * An adaptive anti-sparseness post-processing procedure is
- * applied to the fixed codebook vector in order to
- * reduce perceptual artifacts arising from the sparseness
- * of the algebraic fixed codebook vectors with only
- * a few non-zero samples per subframe.
- *
- * Returns:
- * void
- */
- void D_ACELP_phase_dispersion(Word16 gain_code, Word16 gain_pit, Word16 code[],
- Word16 mode, Word16 disp_mem[])
- {
- Word32 code2[2 * L_SUBFR] = {0};
- Word32 i, j, state;
- Word16 *prev_gain_pit, *prev_gain_code, *prev_state;
- prev_state = disp_mem;
- prev_gain_code = disp_mem + 1;
- prev_gain_pit = disp_mem + 2;
- if(gain_pit < 9830) /* 0.6 in Q14 */
- {
- state = 0;
- }
- else if(gain_pit < 14746) /* 0.9 in Q14 */
- {
- state = 1;
- }
- else
- {
- state = 2;
- }
- for(i = 5; i > 0; i--)
- {
- prev_gain_pit[i] = prev_gain_pit[i - 1];
- }
- prev_gain_pit[0] = gain_pit;
- if((gain_code - *prev_gain_code) > (*prev_gain_code << 1))
- {
- /* onset */
- if(state < 2)
- {
- state = state + 1;
- }
- }
- else
- {
- j = 0;
- for(i = 0; i < 6; i++)
- {
- if(prev_gain_pit[i] < 9830) /* 0.6 in Q14 */
- j = (j + 1);
- }
- if(j > 2)
- {
- state = 0;
- }
- if((state - *prev_state) > 1)
- {
- state = state - 1;
- }
- }
- *prev_gain_code = gain_code;
- *prev_state = (Word16)state;
- /* circular convolution */
- state = state + mode; /* level of dispersion */
- if(state == 0)
- {
- for(i = 0; i < L_SUBFR; i++)
- {
- if(code[i] != 0)
- {
- for(j = 0; j < L_SUBFR; j++)
- {
- code2[i + j] = code2[i + j] +
- (((code[i] * D_ROM_ph_imp_low[j]) + 0x4000) >> 15);
- }
- }
- }
- }
- else if(state == 1)
- {
- for(i = 0; i < L_SUBFR; i++)
- {
- if(code[i] != 0)
- {
- for(j = 0; j < L_SUBFR; j++)
- {
- code2[i + j] = code2[i + j] +
- (((code[i] * D_ROM_ph_imp_mid[j]) + 0x4000) >> 15);
- }
- }
- }
- }
- if(state < 2)
- {
- for(i = 0; i < L_SUBFR; i++)
- {
- code[i] = (Word16)(code2[i] + code2[i + L_SUBFR]);
- }
- }
- return;
- }