path: root/libSBRdec/src/psbitdec.cpp

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

                     (C) Copyright Fraunhofer IIS (2005)
                               All Rights Reserved

    Please be advised that this software and/or program delivery is
    Confidential Information of Fraunhofer and subject to and covered by the

    Fraunhofer IIS Software Evaluation Agreement
    between Google Inc. and  Fraunhofer
    effective and in full force since March 1, 2012.

    You may use this software and/or program only under the terms and
    conditions described in the above mentioned Fraunhofer IIS Software
    Evaluation Agreement. Any other and/or further use requires a separate agreement.


   This software and/or program is protected by copyright law and international
   treaties. Any reproduction or distribution of this software and/or program,
   or any portion of it, may result in severe civil and criminal penalties, and
   will be prosecuted to the maximum extent possible under law.

  $Id$

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

#include "psbitdec.h"


#include "sbr_rom.h"
#include "huff_dec.h"

/* PS dec privat functions */
SBR_ERROR ResetPsDec(HANDLE_PS_DEC h_ps_d);
void ResetPsDeCor   (HANDLE_PS_DEC h_ps_d);

/***************************************************************************/
/*!
  \brief  huffman decoding by codebook table

  \return index of huffman codebook table

****************************************************************************/
static SCHAR
decode_huff_cw (Huffman h,                      /*!< pointer to huffman codebook table */
                HANDLE_FDK_BITSTREAM hBitBuf,   /*!< Handle to Bitbuffer */
                int *length)                    /*!< length of huffman codeword (or NULL) */
{
  UCHAR bit = 0;
  SCHAR index = 0;
  UCHAR bitCount = 0;

  while (index >= 0) {
    bit = FDKreadBits (hBitBuf, 1);
    bitCount++;
    index = h[index][bit];
  }
  if (length) {
    *length = bitCount;
  }
  return( index+64 ); /* Add offset */
}

/***************************************************************************/
/*!
  \brief  helper function - limiting of value to min/max values

  \return limited value

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

static SCHAR
limitMinMax(SCHAR i,
            SCHAR min,
            SCHAR max)
{
  if (i<min)
    return min;
  else if (i>max)
    return max;
  else
    return i;
}

/***************************************************************************/
/*!
  \brief  Decodes delta values in-place and updates
          data buffers according to quantization classes.

  When delta coded in frequency the first element is deltacode from zero.
  aIndex buffer is decoded from delta values to actual values.

  \return none

****************************************************************************/
static void
deltaDecodeArray(SCHAR enable,
                 SCHAR *aIndex,          /*!< ICC/IID parameters */
                 SCHAR *aPrevFrameIndex, /*!< ICC/IID parameters  of previous frame */
                 SCHAR DtDf,
                 UCHAR nrElements,       /*!< as conveyed in bitstream */
                                         /*!< output array size: nrElements*stride */
                 UCHAR stride,           /*!< 1=dflt, 2=half freq. resolution */
                 SCHAR minIdx,
                 SCHAR maxIdx)
{
  int i;

  /* Delta decode */
  if ( enable==1 ) {
    if (DtDf == 0)  {   /* Delta coded in freq */
      aIndex[0] = 0 + aIndex[0];
      aIndex[0] = limitMinMax(aIndex[0],minIdx,maxIdx);
      for (i = 1; i < nrElements; i++) {
        aIndex[i] = aIndex[i-1] + aIndex[i];
        aIndex[i] = limitMinMax(aIndex[i],minIdx,maxIdx);
      }
    }
    else { /* Delta time */
      for (i = 0; i < nrElements; i++) {
        aIndex[i] = aPrevFrameIndex[i*stride] + aIndex[i];
        aIndex[i] = limitMinMax(aIndex[i],minIdx,maxIdx);
      }
    }
  }
  else { /* No data is sent, set index to zero */
    for (i = 0; i < nrElements; i++) {
      aIndex[i] = 0;
    }
  }
  if (stride==2) {
    for (i=nrElements*stride-1; i>0; i--) {
      aIndex[i] = aIndex[i>>1];
    }
  }
}

/***************************************************************************/
/*!
  \brief Mapping of ICC/IID parameters to 20 stereo bands

  \return none

****************************************************************************/
static void map34IndexTo20 (SCHAR *aIndex, /*!< decoded ICC/IID parameters */
                            UCHAR noBins)  /*!< number of stereo bands     */
{
  aIndex[0]  = (2*aIndex[0]+aIndex[1])/3;
  aIndex[1]  = (aIndex[1]+2*aIndex[2])/3;
  aIndex[2]  = (2*aIndex[3]+aIndex[4])/3;
  aIndex[3]  = (aIndex[4]+2*aIndex[5])/3;
  aIndex[4]  = (aIndex[6]+aIndex[7])/2;
  aIndex[5]  = (aIndex[8]+aIndex[9])/2;
  aIndex[6]  = aIndex[10];
  aIndex[7]  = aIndex[11];
  aIndex[8]  = (aIndex[12]+aIndex[13])/2;
  aIndex[9]  = (aIndex[14]+aIndex[15])/2;
  aIndex[10] = aIndex[16];
  /* For IPD/OPD it stops here */

  if (noBins == NO_HI_RES_BINS)
  {
    aIndex[11] = aIndex[17];
    aIndex[12] = aIndex[18];
    aIndex[13] = aIndex[19];
    aIndex[14] = (aIndex[20]+aIndex[21])/2;
    aIndex[15] = (aIndex[22]+aIndex[23])/2;
    aIndex[16] = (aIndex[24]+aIndex[25])/2;
    aIndex[17] = (aIndex[26]+aIndex[27])/2;
    aIndex[18] = (aIndex[28]+aIndex[29]+aIndex[30]+aIndex[31])/4;
    aIndex[19] = (aIndex[32]+aIndex[33])/2;
  }
}

/***************************************************************************/
/*!
  \brief  Decodes delta coded IID, ICC, IPD and OPD indices

  \return PS processing flag. If set to 1

****************************************************************************/
int
DecodePs( struct PS_DEC *h_ps_d,      /*!< PS handle */
          const UCHAR    frameError ) /*!< Flag telling that frame had errors */
{
  MPEG_PS_BS_DATA *pBsData;
  UCHAR gr, env;
  int   bPsHeaderValid, bPsDataAvail;

  /* Shortcuts to avoid deferencing and keep the code readable */
  pBsData = &h_ps_d->bsData[h_ps_d->processSlot].mpeg;
  bPsHeaderValid = pBsData->bPsHeaderValid;
  bPsDataAvail = (h_ps_d->bPsDataAvail[h_ps_d->processSlot] == ppt_mpeg) ? 1 : 0;

 /***************************************************************************************
  * Decide whether to process or to conceal PS data or not.                             */

  if ( ( h_ps_d->psDecodedPrv && !frameError && !bPsDataAvail)
    || (!h_ps_d->psDecodedPrv && (frameError || !bPsDataAvail || !bPsHeaderValid)) ) {
    /* Don't apply PS processing.
     * Declare current PS header and bitstream data invalid. */
    pBsData->bPsHeaderValid = 0;
    h_ps_d->bPsDataAvail[h_ps_d->processSlot] = ppt_none;
    return (0);
  }

  if (frameError || !bPsHeaderValid)
  { /* no new PS data available (e.g. frame loss) */
    /* => keep latest data constant (i.e. FIX with noEnv=0) */
    pBsData->noEnv = 0;
  }

 /***************************************************************************************
  * Decode bitstream payload or prepare parameter for concealment:
  */
  for (env=0; env<pBsData->noEnv; env++) {
    SCHAR *aPrevIidIndex;
    SCHAR *aPrevIccIndex;

    UCHAR noIidSteps = pBsData->bFineIidQ?NO_IID_STEPS_FINE:NO_IID_STEPS;

    if (env==0) {
      aPrevIidIndex = h_ps_d->specificTo.mpeg.aIidPrevFrameIndex;
      aPrevIccIndex = h_ps_d->specificTo.mpeg.aIccPrevFrameIndex;
    }
    else {
      aPrevIidIndex = pBsData->aaIidIndex[env-1];
      aPrevIccIndex = pBsData->aaIccIndex[env-1];
    }

    deltaDecodeArray(pBsData->bEnableIid,
                     pBsData->aaIidIndex[env],
                     aPrevIidIndex,
                     pBsData->abIidDtFlag[env],
                     FDK_sbrDecoder_aNoIidBins[pBsData->freqResIid],
                     (pBsData->freqResIid)?1:2,
                     -noIidSteps,
                     noIidSteps);

    deltaDecodeArray(pBsData->bEnableIcc,
                     pBsData->aaIccIndex[env],
                     aPrevIccIndex,
                     pBsData->abIccDtFlag[env],
                     FDK_sbrDecoder_aNoIccBins[pBsData->freqResIcc],
                     (pBsData->freqResIcc)?1:2,
                     0,
                     NO_ICC_STEPS-1);
  }   /* for (env=0; env<pBsData->noEnv; env++) */

  /* handling of FIX noEnv=0 */
  if (pBsData->noEnv==0) {
    /* set noEnv=1, keep last parameters or force 0 if not enabled */
    pBsData->noEnv = 1;

    if (pBsData->bEnableIid) {
      for (gr = 0; gr < NO_HI_RES_IID_BINS; gr++) {
        pBsData->aaIidIndex[pBsData->noEnv-1][gr] =
          h_ps_d->specificTo.mpeg.aIidPrevFrameIndex[gr];
      }
    }
    else {
      for (gr = 0; gr < NO_HI_RES_IID_BINS; gr++) {
        pBsData->aaIidIndex[pBsData->noEnv-1][gr] = 0;
      }
    }

    if (pBsData->bEnableIcc) {
      for (gr = 0; gr < NO_HI_RES_ICC_BINS; gr++) {
        pBsData->aaIccIndex[pBsData->noEnv-1][gr] =
          h_ps_d->specificTo.mpeg.aIccPrevFrameIndex[gr];
      }
    }
    else {
      for (gr = 0; gr < NO_HI_RES_ICC_BINS; gr++) {
        pBsData->aaIccIndex[pBsData->noEnv-1][gr] = 0;
      }
    }
  }

  /* Update previous frame index buffers */
  for (gr = 0; gr < NO_HI_RES_IID_BINS; gr++) {
    h_ps_d->specificTo.mpeg.aIidPrevFrameIndex[gr] =
      pBsData->aaIidIndex[pBsData->noEnv-1][gr];
  }
  for (gr = 0; gr < NO_HI_RES_ICC_BINS; gr++) {
    h_ps_d->specificTo.mpeg.aIccPrevFrameIndex[gr] =
      pBsData->aaIccIndex[pBsData->noEnv-1][gr];
  }

  /* PS data from bitstream (if avail) was decoded now */
  h_ps_d->bPsDataAvail[h_ps_d->processSlot] = ppt_none;

  /* handling of env borders for FIX & VAR */
  if (pBsData->bFrameClass == 0) {
    /* FIX_BORDERS NoEnv=0,1,2,4 */
    pBsData->aEnvStartStop[0] = 0;
    for (env=1; env<pBsData->noEnv; env++) {
      pBsData->aEnvStartStop[env] =
        (env * h_ps_d->noSubSamples) / pBsData->noEnv;
    }
    pBsData->aEnvStartStop[pBsData->noEnv] = h_ps_d->noSubSamples;
    /* 1024 (32 slots) env borders:  0, 8, 16, 24, 32 */
    /*  960 (30 slots) env borders:  0, 7, 15, 22, 30 */
  }
  else {   /* if (h_ps_d->bFrameClass == 0) */
    /* VAR_BORDERS NoEnv=1,2,3,4 */
    pBsData->aEnvStartStop[0] = 0;

    /* handle case aEnvStartStop[noEnv]<noSubSample for VAR_BORDERS by
       duplicating last PS parameters and incrementing noEnv */
    if (pBsData->aEnvStartStop[pBsData->noEnv] < h_ps_d->noSubSamples) {
      for (gr = 0; gr < NO_HI_RES_IID_BINS; gr++) {
        pBsData->aaIidIndex[pBsData->noEnv][gr] =
          pBsData->aaIidIndex[pBsData->noEnv-1][gr];
      }
      for (gr = 0; gr < NO_HI_RES_ICC_BINS; gr++) {
        pBsData->aaIccIndex[pBsData->noEnv][gr] =
          pBsData->aaIccIndex[pBsData->noEnv-1][gr];
      }
      pBsData->noEnv++;
      pBsData->aEnvStartStop[pBsData->noEnv] = h_ps_d->noSubSamples;
    }

    /* enforce strictly monotonic increasing borders */
    for (env=1; env<pBsData->noEnv; env++) {
      UCHAR thr;
      thr = (UCHAR)h_ps_d->noSubSamples - (pBsData->noEnv - env);
      if (pBsData->aEnvStartStop[env] > thr) {
        pBsData->aEnvStartStop[env] = thr;
      }
      else {
        thr = pBsData->aEnvStartStop[env-1]+1;
        if (pBsData->aEnvStartStop[env] < thr) {
          pBsData->aEnvStartStop[env] = thr;
        }
      }
    }
  }   /* if (h_ps_d->bFrameClass == 0) ... else */

  /* copy data prior to possible 20<->34 in-place mapping */
  for (env=0; env<pBsData->noEnv; env++) {
    UCHAR i;
    for (i=0; i<NO_HI_RES_IID_BINS; i++) {
      h_ps_d->specificTo.mpeg.coef.aaIidIndexMapped[env][i] = pBsData->aaIidIndex[env][i];
    }
    for (i=0; i<NO_HI_RES_ICC_BINS; i++) {
      h_ps_d->specificTo.mpeg.coef.aaIccIndexMapped[env][i] = pBsData->aaIccIndex[env][i];
    }
  }


  /* MPEG baseline PS */
  /* Baseline version of PS always uses the hybrid filter structure with 20 stereo bands. */
  /* If ICC/IID parameters for 34 stereo bands are decoded they have to be mapped to 20   */
  /* stereo bands.                                                                        */
  /* Additionaly the IPD/OPD parameters won't be used.                                    */

  for (env=0; env<pBsData->noEnv; env++) {
    if (pBsData->freqResIid == 2)
      map34IndexTo20 (h_ps_d->specificTo.mpeg.coef.aaIidIndexMapped[env], NO_HI_RES_IID_BINS);
    if (pBsData->freqResIcc == 2)
      map34IndexTo20 (h_ps_d->specificTo.mpeg.coef.aaIccIndexMapped[env], NO_HI_RES_ICC_BINS);

    /* IPD/OPD is disabled in baseline version and thus was removed here */
  }

  return (1);
}


/***************************************************************************/
/*!

  \brief  Reads parametric stereo data from bitstream

  \return

****************************************************************************/
unsigned int
ReadPsData (HANDLE_PS_DEC h_ps_d,          /*!< handle to struct PS_DEC */
            HANDLE_FDK_BITSTREAM hBitBuf,  /*!< handle to struct BIT_BUF */
            int nBitsLeft                  /*!< max number of bits available */
           )
{
  MPEG_PS_BS_DATA *pBsData;

  UCHAR     gr, env;
  SCHAR     dtFlag;
  INT       startbits;
  Huffman   CurrentTable;
  SCHAR     bEnableHeader;

  if (!h_ps_d)
    return 0;

  pBsData = &h_ps_d->bsData[h_ps_d->bsReadSlot].mpeg;

  if (h_ps_d->bsReadSlot != h_ps_d->bsLastSlot) {
    /* Copy last header data */
    FDKmemcpy(pBsData, &h_ps_d->bsData[h_ps_d->bsLastSlot].mpeg, sizeof(MPEG_PS_BS_DATA));
  }


  startbits = (INT) FDKgetValidBits(hBitBuf);

  bEnableHeader = (SCHAR) FDKreadBits (hBitBuf, 1);

  /* Read header */
  if (bEnableHeader) {
    pBsData->bPsHeaderValid = 1;
    pBsData->bEnableIid = (UCHAR) FDKreadBits (hBitBuf, 1);
    if (pBsData->bEnableIid) {
      pBsData->modeIid = (UCHAR) FDKreadBits (hBitBuf, 3);
    }

    pBsData->bEnableIcc = (UCHAR) FDKreadBits (hBitBuf, 1);
    if (pBsData->bEnableIcc) {
      pBsData->modeIcc = (UCHAR) FDKreadBits (hBitBuf, 3);
    }

    pBsData->bEnableExt = (UCHAR) FDKreadBits (hBitBuf, 1);
  }

  pBsData->bFrameClass = (UCHAR) FDKreadBits (hBitBuf, 1);
  if (pBsData->bFrameClass == 0) {
    /* FIX_BORDERS NoEnv=0,1,2,4 */
    pBsData->noEnv = FDK_sbrDecoder_aFixNoEnvDecode[(UCHAR) FDKreadBits (hBitBuf, 2)];
    /* all additional handling of env borders is now in DecodePs() */
  }
  else {
    /* VAR_BORDERS NoEnv=1,2,3,4 */
    pBsData->noEnv = 1+(UCHAR) FDKreadBits (hBitBuf, 2);
    for (env=1; env<pBsData->noEnv+1; env++)
      pBsData->aEnvStartStop[env] = ((UCHAR) FDKreadBits (hBitBuf, 5)) + 1;
    /* all additional handling of env borders is now in DecodePs() */
  }

  /* verify that IID & ICC modes (quant grid, freq res) are supported */
  if ((pBsData->modeIid > 5) || (pBsData->modeIcc > 5)) {
    /* no useful PS data could be read from bitstream */
    h_ps_d->bPsDataAvail[h_ps_d->bsReadSlot] = ppt_none;
    /* discard all remaining bits */
    nBitsLeft -= startbits - FDKgetValidBits(hBitBuf);
    while (nBitsLeft) {
      int i = nBitsLeft;
      if (i>8) {
        i = 8;
      }
      FDKreadBits (hBitBuf, i);
      nBitsLeft -= i;
    }
    return (startbits - FDKgetValidBits(hBitBuf));
  }

  if (pBsData->modeIid > 2){
    pBsData->freqResIid = pBsData->modeIid-3;
    pBsData->bFineIidQ = 1;
  }
  else{
    pBsData->freqResIid = pBsData->modeIid;
    pBsData->bFineIidQ = 0;
  }

  if (pBsData->modeIcc > 2){
    pBsData->freqResIcc = pBsData->modeIcc-3;
  }
  else{
    pBsData->freqResIcc = pBsData->modeIcc;
  }


  /* Extract IID data */
  if (pBsData->bEnableIid) {
    for (env=0; env<pBsData->noEnv; env++) {
      dtFlag = (SCHAR)FDKreadBits (hBitBuf, 1);
      if (!dtFlag)
      {
        if (pBsData->bFineIidQ)
          CurrentTable = (Huffman)&aBookPsIidFineFreqDecode;
        else
          CurrentTable = (Huffman)&aBookPsIidFreqDecode;
      }
      else
      {
        if (pBsData->bFineIidQ)
         CurrentTable = (Huffman)&aBookPsIidFineTimeDecode;
        else
          CurrentTable = (Huffman)&aBookPsIidTimeDecode;
      }

      for (gr = 0; gr < FDK_sbrDecoder_aNoIidBins[pBsData->freqResIid]; gr++)
        pBsData->aaIidIndex[env][gr] = decode_huff_cw(CurrentTable,hBitBuf,NULL);
      pBsData->abIidDtFlag[env] = dtFlag;
    }
  }

  /* Extract ICC data */
  if (pBsData->bEnableIcc) {
    for (env=0; env<pBsData->noEnv; env++) {
      dtFlag = (SCHAR)FDKreadBits (hBitBuf, 1);
      if (!dtFlag)
        CurrentTable = (Huffman)&aBookPsIccFreqDecode;
      else
        CurrentTable = (Huffman)&aBookPsIccTimeDecode;

      for (gr = 0; gr < FDK_sbrDecoder_aNoIccBins[pBsData->freqResIcc]; gr++)
        pBsData->aaIccIndex[env][gr] = decode_huff_cw(CurrentTable,hBitBuf,NULL);
      pBsData->abIccDtFlag[env] = dtFlag;
    }
  }

  if (pBsData->bEnableExt) {

    /*!
    Decoders that support only the baseline version of the PS tool are allowed
    to ignore the IPD/OPD data, but according header data has to be parsed.
    ISO/IEC 14496-3 Subpart 8 Annex 4
    */

    int cnt = FDKreadBits(hBitBuf, PS_EXTENSION_SIZE_BITS);
    if (cnt == (1<<PS_EXTENSION_SIZE_BITS)-1) {
      cnt += FDKreadBits(hBitBuf, PS_EXTENSION_ESC_COUNT_BITS);
    }
    while (cnt--)
      FDKreadBits(hBitBuf, 8);
  }


  /* new PS data was read from bitstream */
  h_ps_d->bPsDataAvail[h_ps_d->bsReadSlot] = ppt_mpeg;



  return (startbits - FDKgetValidBits(hBitBuf));
}