g729ev_g729_lpc.c

最新的ITU-T的宽带语音编解码标准G.729.1,是对原先的G.729的最好的调整.码流输出速率可以进行自适应调整.满足未来通信要求.希望对大家有所帮助.

/*-------------------------------------------------------------*
 *  find the sum and diff. pol. F1(z) and F2(z)                *
 *    F1(z) <--- F1(z)/(1+z**-1) & F2(z) <--- F2(z)/(1-z**-1)  *
 *                                                             *
 * f1[0] = 1.0;                                                *
 * f2[0] = 1.0;                                                *
 *                                                             *
 * FOR(i = 0; i< G729EV_G729_NC; i++)                                     *
 * {                                                           *
 *   f1[i+1] = a[i+1] + a[M-i] - f1[i] ;                       *
 *   f2[i+1] = a[i+1] - a[M-i] + f2[i] ;                       *
 * }                                                           *
 *-------------------------------------------------------------*/

  ovf_coef = 0;
  pChebps = G729EV_G729_Chebps_11;

#ifdef WMOPS
  move16();
#endif

  f1[0] = 2048;                 /* f1[0] = 1.0 is in Q11 */
  f2[0] = 2048;                 /* f2[0] = 1.0 is in Q11 */

#ifdef WMOPS
  move16();
  move16();
#endif

  FOR(i = 0; i < G729EV_G729_NC; i++)
  {
    Overflow = 0;
#ifdef WMOPS
    move16();
#endif
    t0 = L_mult(a[i + 1], 16384); /* x = (a[i+1] + a[M-i]) >> 1        */
    t0 = L_mac(t0, a[G729EV_G729_M - i], 16384);  /*    -> From Q12 to Q11             */
    x = extract_h(t0);
    if (Overflow != 0)
    {
      ovf_coef = 1;
#ifdef WMOPS
      move16();
#endif
    }

    Overflow = 0;
#ifdef WMOPS
    move16();
    move16();
#endif
    f1[i + 1] = sub(x, f1[i]);  /* f1[i+1] = a[i+1] + a[M-i] - f1[i] */
    if (Overflow != 0)
    {
      ovf_coef = 1;
#ifdef WMOPS
      move16();
#endif
    }

    Overflow = 0;
#ifdef WMOPS
    move16();
#endif
    t0 = L_mult(a[i + 1], 16384); /* x = (a[i+1] - a[M-i]) >> 1        */
    t0 = L_msu(t0, a[G729EV_G729_M - i], 16384);  /*    -> From Q12 to Q11             */
    x = extract_h(t0);
    if (Overflow != 0)
    {
      ovf_coef = 1;
#ifdef WMOPS
      move16();
#endif
    }

    Overflow = 0;
#ifdef WMOPS
    move16();
    move16();
#endif
    f2[i + 1] = add(x, f2[i]);  /* f2[i+1] = a[i+1] - a[M-i] + f2[i] */
    if (Overflow != 0)
    {
      ovf_coef = 1;
#ifdef WMOPS
      move16();
#endif
    }
  }

  IF(ovf_coef != 0)
  {
    /*printf("===== OVF ovf_coef =====\n"); */

    pChebps = G729EV_G729_Chebps_10;

    f1[0] = 1024;               /* f1[0] = 1.0 is in Q10 */
    f2[0] = 1024;               /* f2[0] = 1.0 is in Q10 */

#ifdef WMOPS
    move16();
    move16();
#endif

    FOR(i = 0; i < G729EV_G729_NC; i++)
    {
      t0 = L_mult(a[i + 1], 8192);  /* x = (a[i+1] + a[M-i]) >> 1        */
      t0 = L_mac(t0, a[G729EV_G729_M - i], 8192); /*    -> From Q11 to Q10             */
      x = extract_h(t0);
      f1[i + 1] = sub(x, f1[i]);  /* f1[i+1] = a[i+1] + a[M-i] - f1[i] */

      t0 = L_mult(a[i + 1], 8192);  /* x = (a[i+1] - a[M-i]) >> 1        */
      t0 = L_msu(t0, a[G729EV_G729_M - i], 8192); /*    -> From Q11 to Q10             */
      x = extract_h(t0);
      f2[i + 1] = add(x, f2[i]);  /* f2[i+1] = a[i+1] - a[M-i] + f2[i] */

#ifdef WMOPS
      move16();
      move16();
#endif
    }
  }

/*-------------------------------------------------------------*
 * find the LSPs using the Chebichev pol. evaluation           *
 *-------------------------------------------------------------*/

  nf = 0;                       /* number of found frequencies */
  ip = 0;                       /* indicator for f1 or f2      */

  coef = f1;

  xlow = grid[0];
  ylow = (*pChebps) (xlow, coef, G729EV_G729_NC);

  j = 0;

#ifdef WMOPS
  move16();
  move16();
  move16();
  move16();

  test();
#endif

  WHILE((sub(nf, G729EV_G729_M) < 0) && (sub(j, G729EV_G729_GRID_POINTS) < 0))
  {
    j = add(j, 1);
    xhigh = xlow;
    yhigh = ylow;
    xlow = grid[j];
    ylow = (*pChebps) (xlow, coef, G729EV_G729_NC);
#ifdef WMOPS
    move16();
    move16();
    move16();
#endif

    L_temp = L_mult(ylow, yhigh);

    IF(L_temp <= (Word32) 0)
    {

      /* divide 4 times the interval */

      FOR(i = 0; i < 4; i++)
      {
        xmid = add(shr(xlow, 1), shr(xhigh, 1));  /* xmid = (xlow + xhigh)/2 */

        ymid = (*pChebps) (xmid, coef, G729EV_G729_NC);

        L_temp = L_mult(ylow, ymid);
        IF(L_temp <= (Word32) 0)
        {
          yhigh = ymid;
          xhigh = xmid;
        }
        ELSE
        {
          ylow = ymid;
          xlow = xmid;
        }
#ifdef WMOPS
        move16();
        move16();
#endif
      }

    /*-------------------------------------------------------------*
     * Linear interpolation                                        *
     *    xint = xlow - ylow*(xhigh-xlow)/(yhigh-ylow);            *
     *-------------------------------------------------------------*/

      x = sub(xhigh, xlow);
      y = sub(yhigh, ylow);

      IF(y == 0)
      {
        xint = xlow;
#ifdef WMOPS
        move16();
#endif
      }
      ELSE
      {
        sign = y;
#ifdef WMOPS
        move16();
#endif
        y = abs_s(y);
        exp = norm_s(y);
        y = shl(y, exp);
        y = div_s((Word16) 16383, y);
        t0 = L_mult(x, y);
        t0 = L_shr(t0, sub(20, exp));
        y = extract_l(t0);      /* y= (xhigh-xlow)/(yhigh-ylow) in Q11 */

        if (sign < 0)
          y = negate(y);

        t0 = L_mult(ylow, y);   /* result in Q26 */
        t0 = L_shr(t0, 11);     /* result in Q15 */
        xint = sub(xlow, extract_l(t0));  /* xint = xlow - ylow*y */
      }

      lsp[nf] = xint;
      xlow = xint;
#ifdef WMOPS
      move16();
      move16();
#endif
      nf = add(nf, 1);

      IF(ip == 0)
      {
        ip = 1;
        coef = f2;
      }
      ELSE
      {
        ip = 0;
        coef = f1;
      }
      ylow = (*pChebps) (xlow, coef, G729EV_G729_NC);
#ifdef WMOPS
      move16();
      move16();
#endif

    }
  }

  /* Check if M roots found */
  IF(sub(nf, G729EV_G729_M) < 0)
  {
    FOR(i = 0; i < G729EV_G729_M; i++)
    {
      lsp[i] = old_lsp[i];
#ifdef WMOPS
      move16();
#endif
    }

    /* printf("\n !!Not 10 roots found in Az_lsp()!!!\n"); */
  }

  return;
}

/*--------------------------------------------------------------*
 * function  G729EV_G729_Chebps_11, G729EV_G729_Chebps_10:                              *
 *           ~~~~~~~~~~~~~~~~~~~~                               *
 *    Evaluates the Chebichev polynomial series                 *
 *--------------------------------------------------------------*
 *                                                              *
 *  The polynomial order is                                     *
 *     n = M/2   (M is the prediction order)                    *
 *  The polynomial is given by                                  *
 *    C(x) = T_n(x) + f(1)T_n-1(x) + ... +f(n-1)T_1(x) + f(n)/2 *
 * Arguments:                                                   *
 *  x:     input value of evaluation; x = cos(frequency) in Q15 *
 *  f[]:   coefficients of the pol.                             *
 *                         in Q11(Chebps_11), in Q10(Chebps_10) *
 *  n:     order of the pol.                                    *
 *                                                              *
 * The value of C(x) is returned. (Saturated to +-1.99 in Q14)  *
 *                                                              *
 *--------------------------------------------------------------*/
Word16 G729EV_G729_Chebps_11(Word16 x, Word16 f[], Word16 n)
{
  Word32    t0;

  Word16    i, cheb;
  Word16    b0_h, b0_l, b1_h, b1_l, b2_h, b2_l;


  /* Note: All computation are done in Q24. */

  b2_h = 256;                   /* b2 = 1.0 in Q24 DPF */
  b2_l = 0;
#ifdef WMOPS
  move16();
  move16();
#endif

  t0 = L_mult(x, 512);          /* 2*x in Q24          */
  t0 = L_mac(t0, f[1], 4096);   /* + f[1] in Q24       */
  L_Extract(t0, &b1_h, &b1_l);  /* b1 = 2*x + f[1]     */

  FOR(i = 2; i < n; i++)
  {
    t0 = Mpy_32_16(b1_h, b1_l, x);  /* t0 = 2.0*x*b1              */
    t0 = L_shl(t0, 1);
    t0 = L_mac(t0, b2_h, (Word16) - 32768L);  /* t0 = 2.0*x*b1 - b2         */
    t0 = L_msu(t0, b2_l, 1);
    t0 = L_mac(t0, f[i], 4096);     /* t0 = 2.0*x*b1 - b2 + f[i]; */

    L_Extract(t0, &b0_h, &b0_l);    /* b0 = 2.0*x*b1 - b2 + f[i]; */

    b2_l = b1_l;                    /* b2 = b1; */
    b2_h = b1_h;
    b1_l = b0_l;                    /* b1 = b0; */
    b1_h = b0_h;

#ifdef WMOPS
    move16();
    move16();
    move16();
    move16();
#endif
  }

  t0 = Mpy_32_16(b1_h, b1_l, x);  /* t0 = x*b1;              */
  t0 = L_mac(t0, b2_h, (Word16) - 32768L);  /* t0 = x*b1 - b2          */
  t0 = L_msu(t0, b2_l, 1);
  t0 = L_mac(t0, f[i], 2048);   /* t0 = x*b1 - b2 + f[i]/2 */

  t0 = L_shl(t0, 6);            /* Q24 to Q30 with saturation */
  cheb = extract_h(t0);         /* Result in Q14              */


  return (cheb);
}


Word16 G729EV_G729_Chebps_10(Word16 x, Word16 f[], Word16 n)
{
  Word32    t0;

  Word16    i, cheb;
  Word16    b0_h, b0_l, b1_h, b1_l, b2_h, b2_l;


  /* Note: All computation are done in Q23. */

  b2_h = 128;                   /* b2 = 1.0 in Q23 DPF */
  b2_l = 0;
#ifdef WMOPS
  move16();
  move16();
#endif

  t0 = L_mult(x, 256);          /* 2*x in Q23          */
  t0 = L_mac(t0, f[1], 4096);   /* + f[1] in Q23       */
  L_Extract(t0, &b1_h, &b1_l);  /* b1 = 2*x + f[1]     */

  FOR(i = 2; i < n; i++)
  {
    t0 = Mpy_32_16(b1_h, b1_l, x);  /* t0 = 2.0*x*b1              */
    t0 = L_shl(t0, 1);
    t0 = L_mac(t0, b2_h, (Word16) - 32768L);  /* t0 = 2.0*x*b1 - b2         */
    t0 = L_msu(t0, b2_l, 1);
    t0 = L_mac(t0, f[i], 4096);    /* t0 = 2.0*x*b1 - b2 + f[i]; */

    L_Extract(t0, &b0_h, &b0_l);   /* b0 = 2.0*x*b1 - b2 + f[i]; */

    b2_l = b1_l;                   /* b2 = b1; */
    b2_h = b1_h;
    b1_l = b0_l;                   /* b1 = b0; */
    b1_h = b0_h;
#ifdef WMOPS
    move16();
    move16();
    move16();
    move16();
#endif
  }

  t0 = Mpy_32_16(b1_h, b1_l, x);  /* t0 = x*b1;              */
  t0 = L_mac(t0, b2_h, (Word16) - 32768L);  /* t0 = x*b1 - b2          */
  t0 = L_msu(t0, b2_l, 1);
  t0 = L_mac(t0, f[i], 2048);     /* t0 = x*b1 - b2 + f[i]/2 */

  t0 = L_shl(t0, 7);              /* Q23 to Q30 with saturation */
  cheb = extract_h(t0);           /* Result in Q14              */


  return (cheb);
}