ac3dec_mantissa.cpp

这是在PCA下的基于IPP库示例代码例子,在网上下了IPP的库之后,设置相关参数就可以编译该代码.

/*//////////////////////////////////////////////////////////////////////////////
//
//                  INTEL CORPORATION PROPRIETARY INFORMATION
//     This software is supplied under the terms of a license agreement or
//     nondisclosure agreement with Intel Corporation and may not be copied
//     or disclosed except in accordance with the terms of that agreement.
//          Copyright(c) 2002-2005 Intel Corporation. All Rights Reserved.
//
*/

#include "umc_ac3_decoder.h"
#include "ipps.h"

#define DITHMULT  47989
#define DITHER_GEN(x)                                            \
{                                                                \
  int tmp0, tmp1;                                                \
  tmp0 = (((int)(DITHMULT * mants_tabls.dithtemp)) << 16) >> 16; \
  mants_tabls.dithtemp = (short)tmp0;                            \
  tmp1 = (((int)(DITHMULT * mants_tabls.dithtemp)) << 16) >> 16; \
  mants_tabls.dithtemp = (short)tmp1;                            \
  x = (0.707106781f * 0.5f * (tmp0 + tmp1));                     \
}

//------------------------------------------------------------------------------
/*
 The mapping of coded mantissa value into the actual mantissa value is shown in
 tables Table 7.19 through Table 7.23.
*/
static const Ipp32f q_1[3] =   // Table 7.19 bap=1 (3-Level) Quantization
{
  (-2 << 15) / (Ipp32f)3, 0, (2 << 15) / (Ipp32f)3
};

static const Ipp32f q_2[5] =   // Table 7.20 bap=2 (5-Level) Quantization
{
  (-4 << 15) / (Ipp32f)5, (-2 << 15) / (Ipp32f)5, 0,
  (2 << 15)  / (Ipp32f)5, (4 << 15)  / (Ipp32f)5
};

static const Ipp32f q_3[7] =   // Table 7.21 bap=3 (7-Level) Quantization
{
  (-6 << 15) / (Ipp32f)7, (-4 << 15) / (Ipp32f)7, (-2 << 15) / (Ipp32f)7, 0,
  (2 << 15)  / (Ipp32f)7, (4 << 15)  / (Ipp32f)7, (6 << 15)  / (Ipp32f)7
};

static const Ipp32f q_4[11] =  // Table 7.22 bap=4 (11-Level) Quantization
{
  (-10 << 15) / (Ipp32f)11, (-8 << 15) / (Ipp32f)11, (-6 << 15) / (Ipp32f)11,
  (-4 << 15)  / (Ipp32f)11, (-2 << 15) / (Ipp32f)11,                       0,
  (2 << 15)   / (Ipp32f)11, (4 << 15)  / (Ipp32f)11, (6 << 15)  / (Ipp32f)11,
  (8 << 15)   / (Ipp32f)11, (10 << 15) / (Ipp32f)11
};

static const Ipp32f q_5[15] =  // Table 7.23 bap=5 (15-Level) Quantization
{
  (-14 << 15) / (Ipp32f)15, (-12 << 15) / (Ipp32f)15, (-10 << 15) / (Ipp32f)15,
  (-8 << 15)  / (Ipp32f)15, (-6 << 15)  / (Ipp32f)15, (-4 << 15)  / (Ipp32f)15,
  (-2 << 15)  / (Ipp32f)15,                        0, (2 << 15)   / (Ipp32f)15,
  (4 << 15)   / (Ipp32f)15, (6 << 15)   / (Ipp32f)15, (8 << 15)   / (Ipp32f)15,
  (10 << 15)  / (Ipp32f)15, (12 << 15)  / (Ipp32f)15, (14 << 15)  / (Ipp32f)15
};

//Conversion from bap to number of bits in the mantissas
//zeros account for cases 0,1,2,4 which are special cased
static const Ipp16u  QNTTZTAB[16] = { 0, 0, 0, 3, 0, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16 };
static const Ipp16u  INV_QNTTZTAB[16] =
  { 16, 16, 16, 13, 16, 12, 11, 12, 9, 8, 7, 6, 5, 4, 2, 0 };

int UMC::AC3Decoder::getMantissas(Ipp16u *bap, int do_dither, Ipp32f *mant,
                                  int count)
{
  Ipp16u index;
  int tmp;

  if (do_dither) {
    for (int i = 0; i < count; i++) {
      switch (bap[i]) {
      case 0:
        DITHER_GEN(mant[i]);
        break;
      case 1:
        if (mants_tabls.m_1_pointer > 2) {
          mants_tabls.fast_m_1 = mants_tabls.fastM_9[getbits(5)];
          mants_tabls.m_1_pointer = 0;
        }
        mant[i] = q_1[mants_tabls.fast_m_1[mants_tabls.m_1_pointer++]];
        break;
      case 2:
        if (mants_tabls.m_2_pointer > 2) {
          mants_tabls.fast_m_2 = mants_tabls.fastM_25[getbits(7)];
          mants_tabls.m_2_pointer = 0;
        }
        mant[i] = q_2[mants_tabls.fast_m_2[mants_tabls.m_2_pointer++]];
        break;

      case 3:
        mant[i] = q_3[getbits(3)];
        break;

      case 4:
        if (mants_tabls.m_4_pointer > 1) {
          mants_tabls.fast_m_4 = mants_tabls.fastM_11[getbits(7)];
          mants_tabls.m_4_pointer = 0;
        }

        mant[i] = q_4[mants_tabls.fast_m_4[mants_tabls.m_4_pointer++]];
        break;

      case 5:
        mant[i] = q_5[getbits(4)];
        break;

      default:
        index = QNTTZTAB[bap[i]];
        tmp = getbits(index);
        tmp <<= (32 - index);
        mant[i] = (Ipp32f)(tmp >>16);
      }
    }
  } else {
    for (int i = 0; i < count; i++) {
      switch (bap[i]) {
      case 0:
        mant[i] = 0;
        break;
      case 1:
        if (mants_tabls.m_1_pointer > 2) {
          mants_tabls.fast_m_1 = mants_tabls.fastM_9[getbits(5)];
          mants_tabls.m_1_pointer = 0;
        }
        mant[i] = q_1[mants_tabls.fast_m_1[mants_tabls.m_1_pointer++]];
        break;
      case 2:
        if (mants_tabls.m_2_pointer > 2) {
          mants_tabls.fast_m_2 = mants_tabls.fastM_25[getbits(7)];
          mants_tabls.m_2_pointer = 0;
        }
        mant[i] = q_2[mants_tabls.fast_m_2[mants_tabls.m_2_pointer++]];
        break;

      case 3:
        mant[i] = q_3[getbits(3)];
        break;

      case 4:
        if (mants_tabls.m_4_pointer > 1) {
          mants_tabls.fast_m_4 = mants_tabls.fastM_11[getbits(7)];
          mants_tabls.m_4_pointer = 0;
        }

        mant[i] = q_4[mants_tabls.fast_m_4[mants_tabls.m_4_pointer++]];
        break;

      case 5:
        mant[i] = q_5[getbits(4)];
        break;

      default:
        index = QNTTZTAB[bap[i]];
        tmp = getbits(index);
        tmp <<= (32 - index);
        mant[i] = (Ipp32f)(tmp >>16);
      }
    }
  }

  return 1;
}

int UMC::AC3Decoder::UnpackMantissas(int nblk)
{
  int    i, j;
  Ipp32u done_cpl = 0;
  float  *mant_ptr;
  Ipp16u *bap_ptr;
  Ipp16s *exp_ptr;
  int do_dither = 0;
  int cplChannel = 0;
  int count;

  mants_tabls.m_1_pointer = mants_tabls.m_2_pointer = mants_tabls.m_4_pointer =
    3;

  for (i = 0; i < bsi.nfchans; i++) {
    mant_ptr = &(audblk[nblk]->fbw_mant[i][0]);
    bap_ptr = &(audblk[nblk]->fbw_bap[i][0]);
    do_dither = audblk[nblk]->dithflag[i];

    getMantissas(bap_ptr, do_dither, mant_ptr,
                 audblk[nblk]->endmant[i]);

    if (audblk[nblk]->cplinu && audblk[nblk]->chincpl[i]) {
      j = audblk[nblk]->cplstrtmant;
      mant_ptr = &audblk[nblk]->cpl_mant[j];
      bap_ptr = &audblk[nblk]->cpl_bap[j];
      exp_ptr = (Ipp16s *)&audblk[nblk]->cpl_exp[j];
      count = audblk[nblk]->cplendmant - audblk[nblk]->cplstrtmant;

      if (!done_cpl) {
        getMantissas(bap_ptr, do_dither, mant_ptr, count);
        MakeFloat_32f32f(mant_ptr, exp_ptr, count,
                             &data_vectors.stream_coeffs.cplChannel[cplChannel][j]);
      } else if (do_dither) {
        int ii;

        for (ii = 0; ii < count; ii++) {
          if (bap_ptr[ii] == 0) {
            float tmp;

            DITHER_GEN(mant_ptr[ii]);

            *(int*)(&tmp) = (((112 - (int)exp_ptr[ii]) << 23) & 0x7FFFFFFF);
            data_vectors.stream_coeffs.cplChannel[cplChannel][j + ii] =
              (float)mant_ptr[ii] * tmp;
          } else {
            data_vectors.stream_coeffs.cplChannel[cplChannel][j + ii] =
              data_vectors.stream_coeffs.cplChannel[0][j + ii];
          }
        }
      } else {
        int ii;

        for (ii = 0; ii < count; ii++) {
          if (bap_ptr[ii] == 0) {
            data_vectors.stream_coeffs.cplChannel[cplChannel][j + ii] = 0;
          } else {
            data_vectors.stream_coeffs.cplChannel[cplChannel][j + ii] =
              data_vectors.stream_coeffs.cplChannel[0][j + ii];
          }
        }
      }

      done_cpl = 1;
      cplChannel++;
    }
  }

  if (bsi.lfeon) {
    mant_ptr = &audblk[nblk]->lfe_mant[0];
    bap_ptr = &audblk[nblk]->lfe_bap[0];

    /* There are always 7 mantissas for lfe */
    getMantissas(bap_ptr, 0, mant_ptr, 7);
    mant_ptr += 7;
  }

  return 1;
}