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#include <math.h>
#include "nb_celp.h"
#include "lsp.h"
#include "ltp.h"
#include "quant_lsp.h"
#include "cb_search.h"
#include "filters.h"
#include "os_support.h"
#ifndef NULL
#define NULL 0
#endif
#define LSP_MARGIN .002f
#define SIG_SCALING 1.f
#define NB_DEC_BUFFER (NB_FRAME_SIZE+2*NB_PITCH_END+NB_SUBFRAME_SIZE+12)
#define NB_ORDER 10
#define NB_FRAME_SIZE 160
#define NB_SUBFRAME_SIZE 40
#define NB_NB_SUBFRAMES 4
#define NB_PITCH_START 17
#define NB_PITCH_END 144
struct speex_decode_state {
float excBuf[NB_DEC_BUFFER]; /**< Excitation buffer */
float *exc; /**< Start of excitation frame */
float old_qlsp[10]; /**< Quantized LSPs for previous frame */
float interp_qlpc[10]; /**< Interpolated quantized LPCs */
float mem_sp[10]; /**< Filter memory for synthesis signal */
int first; /**< Is this the first frame? */
};
static const float exc_gain_quant_scal1[2] = {0.70469f, 1.05127f};
struct speex_decode_state *nb_decoder_init(void)
{
struct speex_decode_state *st;
st = malloc(sizeof(*st));
if (!st)
return NULL;
memset(st, 0, sizeof(*st));
st->first = 1;
return st;
}
void nb_decoder_destroy(struct speex_decode_state *state)
{
if (state)
free(state);
}
/* basic decoder using mode3 only */
int nb_decode(struct speex_decode_state *st, SpeexBits *bits, float *out)
{
int i, sub, wideband, mode, qe;
float ol_gain;
float innov[NB_SUBFRAME_SIZE];
float exc32[NB_SUBFRAME_SIZE];
float qlsp[NB_ORDER], interp_qlsp[NB_ORDER];
float ak[NB_ORDER];
if (!bits)
return -1;
st->exc = st->excBuf + 2*NB_PITCH_END + NB_SUBFRAME_SIZE + 6;
/* Decode Sub-modes */
do {
if (speex_bits_remaining(bits) < 5)
return -1;
wideband = speex_bits_unpack_unsigned(bits, 1);
if (wideband) {
printf("wideband not supported\n");
return -2;
}
mode = speex_bits_unpack_unsigned(bits, 4);
if (mode == 15)
return -1;
} while (mode > 8);
if (mode != 3) {
printf("only mode 3 supported\n");
return -2;
}
/* Shift all buffers by one frame */
SPEEX_MOVE(st->excBuf, st->excBuf+NB_FRAME_SIZE,
2*NB_PITCH_END + NB_SUBFRAME_SIZE + 12);
/* Unquantize LSPs */
lsp_unquant_lbr(qlsp, NB_ORDER, bits);
/* Handle first frame */
if (st->first) {
st->first = 0;
for (i=0; i<NB_ORDER; i++)
st->old_qlsp[i] = qlsp[i];
}
/* Get global excitation gain */
qe = speex_bits_unpack_unsigned(bits, 5);
ol_gain = SIG_SCALING*exp(qe/3.5);
/* Loop on subframes */
for (sub=0; sub<4; sub++) {
int offset, q_energy;
float *exc, *sp;
float ener;
offset = NB_SUBFRAME_SIZE*sub;
exc = st->exc + offset;
sp = out + offset;
SPEEX_MEMSET(exc, 0, NB_SUBFRAME_SIZE);
/* Adaptive codebook contribution */
pitch_unquant_3tap(exc, exc32, NB_PITCH_START,
NB_SUBFRAME_SIZE, bits, 0);
sanitize_values32(exc32, -32000, 32000, NB_SUBFRAME_SIZE);
/* Unquantize the innovation */
SPEEX_MEMSET(innov, 0, NB_SUBFRAME_SIZE);
/* Decode sub-frame gain correction */
q_energy = speex_bits_unpack_unsigned(bits, 1);
ener = exc_gain_quant_scal1[q_energy] * ol_gain;
/* Fixed codebook contribution */
split_cb_shape_sign_unquant(innov, bits);
/* De-normalize innovation and update excitation */
signal_mul(innov, innov, ener, NB_SUBFRAME_SIZE);
for (i=0; i<NB_SUBFRAME_SIZE; i++) {
exc[i] = exc32[i] + innov[i];
}
}
SPEEX_COPY(out, &st->exc[-NB_SUBFRAME_SIZE], NB_FRAME_SIZE);
/* Loop on subframes */
for (sub=0; sub<4; sub++) {
const int offset = NB_SUBFRAME_SIZE*sub;
float *sp, *exc;
sp = out + offset;
exc = st->exc + offset;
/* LSP interpolation (quantized and unquantized) */
lsp_interpolate(st->old_qlsp, qlsp, interp_qlsp, NB_ORDER,
sub, NB_NB_SUBFRAMES, LSP_MARGIN);
/* Compute interpolated LPCs (unquantized) */
lsp_to_lpc(interp_qlsp, ak, NB_ORDER);
iir_mem16(sp, st->interp_qlpc, sp, NB_SUBFRAME_SIZE,
NB_ORDER, st->mem_sp);
/* Save for interpolation in next frame */
for (i=0; i<NB_ORDER; i++)
st->interp_qlpc[i] = ak[i];
}
/* Store the LSPs for interpolation in the next frame */
for (i=0; i<NB_ORDER; i++)
st->old_qlsp[i] = qlsp[i];
return 0;
}
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