
   /******************************************************************

       iLBC Speech Coder ANSI-C Source Code

       LPCencode.c

       Copyright (C) The Internet Society (2004).
       All Rights Reserved.

   ******************************************************************/

#include <string.h>

#include "iLBC_define.h"
#include "helpfun.h"
#include "lsf.h"
#include "constants.h"





   /*----------------------------------------------------------------*
    *  lpc analysis (subrutine to LPCencode)
    *---------------------------------------------------------------*/

void SimpleAnalysis(float *lsf, /* (o) lsf coefficients */
  float *data,                  /* (i) new data vector */
  iLBC_Enc_Inst_t * iLBCenc_inst
  /* (i/o) the encoder state structure */
  )
{
  int k, is;
  float temp[BLOCKL_MAX], lp[LPC_FILTERORDER + 1];
  float lp2[LPC_FILTERORDER + 1];
  float r[LPC_FILTERORDER + 1];

  is = LPC_LOOKBACK + BLOCKL_MAX - iLBCenc_inst->blockl;
  memcpy(iLBCenc_inst->lpc_buffer + is, data,
    iLBCenc_inst->blockl * sizeof(float));

  /* No lookahead, last window is asymmetric */

  for (k = 0; k < iLBCenc_inst->lpc_n; k++) {

    is = LPC_LOOKBACK;

    if (k < (iLBCenc_inst->lpc_n - 1)) {
      window(temp, lpc_winTbl, iLBCenc_inst->lpc_buffer, BLOCKL_MAX);
    } else {
      window(temp, lpc_asymwinTbl,
        iLBCenc_inst->lpc_buffer + is, BLOCKL_MAX);
    }

    autocorr(r, temp, BLOCKL_MAX, LPC_FILTERORDER);
    window(r, r, lpc_lagwinTbl, LPC_FILTERORDER + 1);

    levdurb(lp, temp, r, LPC_FILTERORDER);
    bwexpand(lp2, lp, LPC_CHIRP_SYNTDENUM, LPC_FILTERORDER + 1);

    a2lsf(lsf + k * LPC_FILTERORDER, lp2);
  }
  is = LPC_LOOKBACK + BLOCKL_MAX - iLBCenc_inst->blockl;
  memmove(iLBCenc_inst->lpc_buffer,
    iLBCenc_inst->lpc_buffer + LPC_LOOKBACK + BLOCKL_MAX - is,
    is * sizeof(float));
}

   /*----------------------------------------------------------------*





    *  lsf interpolator and conversion from lsf to a coefficients
    *  (subrutine to SimpleInterpolateLSF)
    *---------------------------------------------------------------*/

void LSFinterpolate2a_enc(float *a,     /* (o) lpc coefficients */
  float *lsf1,                  /* (i) first set of lsf coefficients */
  float *lsf2,                  /* (i) second set of lsf coefficients */
  float coef,                   /* (i) weighting coefficient to use between
                                   lsf1 and lsf2 */
  long length                   /* (i) length of coefficient vectors */
  )
{
  float lsftmp[LPC_FILTERORDER];

  interpolate(lsftmp, lsf1, lsf2, coef, length);
  lsf2a(a, lsftmp);
}

   /*----------------------------------------------------------------*
    *  lsf interpolator (subrutine to LPCencode)
    *---------------------------------------------------------------*/

void SimpleInterpolateLSF(float *syntdenum,     /* (o) the synthesis filter denominator
                                                   resulting from the quantized
                                                   interpolated lsf */
  float *weightdenum,           /* (o) the weighting filter denominator
                                   resulting from the unquantized
                                   interpolated lsf */
  float *lsf,                   /* (i) the unquantized lsf coefficients */
  float *lsfdeq,                /* (i) the dequantized lsf coefficients */
  float *lsfold,                /* (i) the unquantized lsf coefficients of
                                   the previous signal frame */
  float *lsfdeqold,             /* (i) the dequantized lsf coefficients of
                                   the previous signal frame */
  int length,                   /* (i) should equate LPC_FILTERORDER */
  iLBC_Enc_Inst_t * iLBCenc_inst
  /* (i/o) the encoder state structure */
  )
{
  int i, pos, lp_length;
  float lp[LPC_FILTERORDER + 1], *lsf2, *lsfdeq2;

  lsf2 = lsf + length;
  lsfdeq2 = lsfdeq + length;
  lp_length = length + 1;

  if (iLBCenc_inst->mode == 30) {
    /* sub-frame 1: Interpolation between old and first





       set of lsf coefficients */

    LSFinterpolate2a_enc(lp, lsfdeqold, lsfdeq,
      lsf_weightTbl_30ms[0], length);
    memcpy(syntdenum, lp, lp_length * sizeof(float));
    LSFinterpolate2a_enc(lp, lsfold, lsf,
      lsf_weightTbl_30ms[0], length);
    bwexpand(weightdenum, lp, LPC_CHIRP_WEIGHTDENUM, lp_length);

    /* sub-frame 2 to 6: Interpolation between first
       and second set of lsf coefficients */

    pos = lp_length;
    for (i = 1; i < iLBCenc_inst->nsub; i++) {
      LSFinterpolate2a_enc(lp, lsfdeq, lsfdeq2,
        lsf_weightTbl_30ms[i], length);
      memcpy(syntdenum + pos, lp, lp_length * sizeof(float));

      LSFinterpolate2a_enc(lp, lsf, lsf2,
        lsf_weightTbl_30ms[i], length);
      bwexpand(weightdenum + pos, lp, LPC_CHIRP_WEIGHTDENUM, lp_length);
      pos += lp_length;
    }
  } else {
    pos = 0;
    for (i = 0; i < iLBCenc_inst->nsub; i++) {
      LSFinterpolate2a_enc(lp, lsfdeqold, lsfdeq,
        lsf_weightTbl_20ms[i], length);
      memcpy(syntdenum + pos, lp, lp_length * sizeof(float));
      LSFinterpolate2a_enc(lp, lsfold, lsf,
        lsf_weightTbl_20ms[i], length);
      bwexpand(weightdenum + pos, lp, LPC_CHIRP_WEIGHTDENUM, lp_length);
      pos += lp_length;
    }
  }

  /* update memory */

  if (iLBCenc_inst->mode == 30) {
    memcpy(lsfold, lsf2, length * sizeof(float));
    memcpy(lsfdeqold, lsfdeq2, length * sizeof(float));
  } else {
    memcpy(lsfold, lsf, length * sizeof(float));
    memcpy(lsfdeqold, lsfdeq, length * sizeof(float));





  }
}

   /*----------------------------------------------------------------*
    *  lsf quantizer (subrutine to LPCencode)
    *---------------------------------------------------------------*/

void SimplelsfQ(float *lsfdeq,  /* (o) dequantized lsf coefficients
                                   (dimension FILTERORDER) */
  int *index,                   /* (o) quantization index */
  float *lsf,                   /* (i) the lsf coefficient vector to be
                                   quantized (dimension FILTERORDER ) */
  int lpc_n                     /* (i) number of lsf sets to quantize */
  )
{
  /* Quantize first LSF with memoryless split VQ */
  SplitVQ(lsfdeq, index, lsf, lsfCbTbl, LSF_NSPLIT,
    dim_lsfCbTbl, size_lsfCbTbl);

  if (lpc_n == 2) {
    /* Quantize second LSF with memoryless split VQ */
    SplitVQ(lsfdeq + LPC_FILTERORDER, index + LSF_NSPLIT,
      lsf + LPC_FILTERORDER, lsfCbTbl, LSF_NSPLIT,
      dim_lsfCbTbl, size_lsfCbTbl);
  }
}

   /*----------------------------------------------------------------*
    *  lpc encoder
    *---------------------------------------------------------------*/

void LPCencode(float *syntdenum,        /* (i/o) synthesis filter coefficients
                                           before/after encoding */
  float *weightdenum,           /* (i/o) weighting denumerator
                                   coefficients before/after
                                   encoding */
  int *lsf_index,               /* (o) lsf quantization index */
  float *data,                  /* (i) lsf coefficients to quantize */
  iLBC_Enc_Inst_t * iLBCenc_inst
  /* (i/o) the encoder state structure */
  )
{
  float lsf[LPC_FILTERORDER * LPC_N_MAX];
  float lsfdeq[LPC_FILTERORDER * LPC_N_MAX];
  int change = 0;

  SimpleAnalysis(lsf, data, iLBCenc_inst);
  SimplelsfQ(lsfdeq, lsf_index, lsf, iLBCenc_inst->lpc_n);





  change = LSF_check(lsfdeq, LPC_FILTERORDER, iLBCenc_inst->lpc_n);
  SimpleInterpolateLSF(syntdenum, weightdenum,
    lsf, lsfdeq, iLBCenc_inst->lsfold,
    iLBCenc_inst->lsfdeqold, LPC_FILTERORDER, iLBCenc_inst);
}
