sp_frm.c

GSM半数率源代码(VSELP) GSM半数率源代码(VSELP)

  get_ipjj(pswLagList[0], &siIPLo, &siRemLo);

  get_ipjj(pswLagList[siNumLags - 1], &siIPHi, &siRemHi);

  /* get lag for first and last C and G required */
  /* ------------------------------------------- */

  siLoLag = sub(siIPLo, CG_INT_MACS / 2 - 1);

  if (siRemHi != 0)
  {
    siHiLag = add(siIPHi, CG_INT_MACS / 2);
  }
  else
  {
    siHiLag = add(siIPHi, CG_INT_MACS / 2 - 1);
  }

  /* transfer needed integer C's and G's to temp buffers */
  /* --------------------------------------------------- */

  psw1 = pswCBuf;
  psw2 = pswGBuf;

  if (siRemLo == 0)
  {

    /* first lag in list is integer: don't care about first entries */
    /* (they will be paired with zero tap in interpolating filter)  */
    /* ------------------------------------------------------------ */

    psw1[0] = 0;
    psw2[0] = 0;
    psw1 = &psw1[1];
    psw2 = &psw2[1];
  }

  for (siI = siLoLag; siI <= siHiLag; siI++)
  {
    psw1[siI - siLoLag] = pswCSfrm[siI - LSMIN];
    psw2[siI - siLoLag] = pswGSfrm[siI - LSMIN];
  }

  if (siRemLo == 0)
  {
    /* make siLoLag correspond to first entry in temp buffers */
    /* ------------------------------------------------------ */
    siLoLag = sub(siLoLag, 1);
  }

  /* interpolate to get C's and G's which correspond to lags in list */
  /* --------------------------------------------------------------- */

  CGInterp(pswLagList, siNumLags, pswCBuf, pswGBuf, siLoLag,
           pswCInterp, pswGInterp);

  /* find max C*C*sgn(C)/G */
  /* --------------------- */

  swPeak = maxCCOverGWithSign(pswCInterp, pswGInterp, &swCmaxSqr, &swGmax,
                              siNumLags);

  /* store best lag and corresponding C*C and G */
  /* ------------------------------------------ */

  pswLTraj[siSfrmIndex] = pswLagList[swPeak];
  pswCCTraj[siSfrmIndex] = swCmaxSqr;
  pswGTraj[siSfrmIndex] = swGmax;

}


/***************************************************************************
 *
 *   FUNCTION NAME: CGInterp
 *
 *   PURPOSE:
 *
 *     Given a list of fractional lags, a C(k) array, and a G(k) array
 *     (k integer), this function generates arrays of C's and G's
 *     corresponding to the list of fractional lags by interpolating the
 *     integer C(k) and G(k) arrays.
 *
 *   INPUTS:
 *
 *     pswLIn[0:siNum-1]
 *
 *                     List of valid lags
 *
 *     siNum
 *
 *                     Length of output lists
 *
 *     pswCIn[0:variable]
 *
 *                     C(k) sequence, k integer.  The zero index corresponds
 *                     to k = siLoIntLag.
 *
 *     pswGIn[0:variable]
 *
 *                     G(k) sequence, k integer.  The zero index corresponds
 *                     to k = siLoIntLag.
 *
 *     siLoIntLag
 *
 *                     Integer lag corresponding to the first entry in the
 *                     C(k) and G(k) input arrays.
 *
 *     ppsrCGIntFilt[0:5][0:5]
 *
 *                     The FIR interpolation filter for C's and G's.
 *
 *   OUTPUTS:
 *
 *     pswCOut[0:siNum-1]
 *
 *                     List of interpolated C's corresponding to pswLIn.
 *
 *     pswGOut[0:siNum-1]
 *
 *                     List of interpolated G's corresponding to pswLIn
 *
 *   RETURN VALUE: none
 *
 *   DESCRIPTION:
 *
 *
 *   REFERENCE:  Sub-clause 4.1.8.2, 4.1.8.3 of GSM Recommendation 06.20
 *
 *   KEYWORDS: lag, interpolateCG
 *
 *************************************************************************/

void   CGInterp(Shortword pswLIn[],
                       short siNum,
                       Shortword pswCIn[],
                       Shortword pswGIn[],
                       short siLoIntLag,
                       Shortword pswCOut[],
                       Shortword pswGOut[])
{

/*_________________________________________________________________________
 |                                                                         |
 |                            Automatic Variables                          |
 |_________________________________________________________________________|
*/
  Shortword i,
         swBig,
         swLoIntLag;
  Shortword swLagInt,
         swTempRem,
         swLagRem;
  Longword L_Temp,
         L_Temp1,
         L_Temp2;

/*_________________________________________________________________________
 |                                                                         |
 |                              Executable Code                            |
 |_________________________________________________________________________|
*/

  swLoIntLag = add(siLoIntLag, (CG_INT_MACS / 2) - 1);

  for (swBig = 0; swBig < siNum; swBig++)
  {

    /* Separate integer and fractional portions of lag */
    /*-------------------------------------------------*/
    L_Temp = L_mult(pswLIn[swBig], INV_OS_FCTR);
    swLagInt = extract_h(L_Temp);

    /* swLagRem = (OS_FCTR - pswLIn[iBig] % OS_FCTR)) */
    /*---------------------------------------------------*/
    swTempRem = extract_l(L_Temp);
    swTempRem = shr(swTempRem, 1);
    swLagRem = swTempRem & SW_MAX;
    swLagRem = mult_r(swLagRem, OS_FCTR);
    swLagRem = sub(OS_FCTR, swLagRem);

    /* Get interpolated C and G values */
    /*--------------------------*/

    L_Temp1 = L_mac(32768, pswCIn[swLagInt - swLoIntLag],
                    ppsrCGIntFilt[0][swLagRem]);
    L_Temp2 = L_mac(32768, pswGIn[swLagInt - swLoIntLag],
                    ppsrCGIntFilt[0][swLagRem]);

    for (i = 1; i <= CG_INT_MACS - 1; i++)
    {
      L_Temp1 = L_mac(L_Temp1, pswCIn[i + swLagInt - swLoIntLag],
                      ppsrCGIntFilt[i][swLagRem]);
      L_Temp2 = L_mac(L_Temp2, pswGIn[i + swLagInt - swLoIntLag],
                      ppsrCGIntFilt[i][swLagRem]);

    }
    pswCOut[swBig] = extract_h(L_Temp1);
    pswGOut[swBig] = extract_h(L_Temp2);
  }
}

/***************************************************************************
 *
 *   FUNCTION NAME: CGInterpValid
 *
 *   PURPOSE:
 *
 *     The purpose of this function is to retrieve the valid (codeable) lags
 *     within one (exclusive) integer sample of the given integer lag, and
 *     interpolate the corresponding C's and G's from the integer arrays
 *
 *   INPUTS:
 *
 *     swFullResLag
 *
 *                     integer lag * OS_FCTR
 *
 *     pswCIn[0:127]
 *
 *                     integer C sequence
 *
 *     pswGIn[0:127]
 *
 *                     integer G sequence
 *
 *     psrLagTbl[0:255]
 *
 *                     reference table of valid (codeable) lags
 *
 *
 *   OUTPUTS:
 *
 *     pswLOut[0:*psiNum-1]
 *
 *                     list of valid lags within 1 of swFullResLag
 *
 *     pswCOut[0:*psiNum-1]
 *
 *                     list of interpolated C's corresponding to pswLOut
 *
 *     pswGOut[0:*psiNum-1]
 *
 *                     list of interpolated G's corresponding to pswLOut
 *
 *   RETURN VALUE:
 *
 *     siNum
 *
 *                     length of output lists
 *
 *   DESCRIPTION:
 *
 *   REFERENCE:  Sub-clause 4.1.8.2, 4.1.9 of GSM Recommendation 06.20
 *
 *   KEYWORDS: CGInterpValid, cginterpvalid, CG_INT_VALID
 *
 *************************************************************************/

short  CGInterpValid(Shortword swFullResLag,
                            Shortword pswCIn[],
                            Shortword pswGIn[],
                            Shortword pswLOut[],
                            Shortword pswCOut[],
                            Shortword pswGOut[])
{

/*_________________________________________________________________________
 |                                                                         |
 |                            Automatic Variables                          |
 |_________________________________________________________________________|
*/

  short int siLowerBound,
         siUpperBound,
         siNum,
         siI;
  Shortword swLag;

/*_________________________________________________________________________
 |                                                                         |
 |                              Executable Code                            |
 |_________________________________________________________________________|
*/

  /* Get lower and upper bounds for valid lags     */
  /* within 1 (exclusive) integer lag of input lag */
  /* --------------------------------------------- */

  swLag = sub(swFullResLag, OS_FCTR);
  swLag = quantLag(swLag, &siLowerBound);
  if (sub(swLag, swFullResLag) != 0)
  {
    siLowerBound = add(siLowerBound, 1);
  }

  swLag = add(swFullResLag, OS_FCTR);
  swLag = quantLag(swLag, &siUpperBound);
  if (sub(swLag, swFullResLag) != 0)
  {
    siUpperBound = sub(siUpperBound, 1);
  }

  /* Get list of full resolution lags whose */
  /* C's and G's will be interpolated       */
  /* -------------------------------------- */

  siNum = sub(siUpperBound, siLowerBound);
  siNum = add(siNum, 1);

  for (siI = 0; siI < siNum; siI++)
  {
    pswLOut[siI] = psrLagTbl[siI + siLowerBound];
  }

  /* Interpolate C's and G's */
  /* ----------------------- */

  CGInterp(pswLOut, siNum, pswCIn, pswGIn, LSMIN, pswCOut,
           pswGOut);

  /* Return the length of the output lists */
  /* ------------------------------------- */

  return (siNum);
}

/***************************************************************************
 *
 *   FUNCTION NAME: compResidEnergy
 *
 *   PURPOSE:
 *
 *     Computes and compares the residual energy from interpolated and
 *     non-interpolated coefficients. From the difference determines
 *     the soft interpolation decision.
 *
 *   INPUTS:
 *
 *     pswSpeech[0:159] ( [0:F_LEN-1] )
 *
 *                     Input speech frame (after high-pass filtering).
 *
 *     ppswInterpCoef[0:3][0:9] ( [0:N_SUB-1][0:NP-1] )
 *
 *                     Set of interpolated LPC direct-form coefficients for
 *                     each subframe.
 *
 *     pswPreviousCoef[0:9} ( [0:NP-1] )
 *
 *                     Set of LPC direct-form coefficients corresponding to
 *                     the previous frame
 *
 *     pswCurrentCoef[0:9} ( [0:NP-1] )
 *
 *                     Set of LPC direct-form coefficients corresponding to
 *                     the current frame
 *
 *     psnsSqrtRs[0:3] ( [0:N_SUB-1] )
 *
 *                     Array of residual energy estimates for each subframe
 *                     based on interpolated coefficients.  Used for scaling.
 *
 *   RETURN:
 *
 *     Returned value indicates the coefficients to use for each subframe:
 *     One indicates interpolated coefficients are to be used, zero indicates
 *     un-interpolated coefficients are to be used.