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#include "EncHRD.h"

#include "CommonLib/ProfileLevelTier.h"

namespace vvenc {

// calculate scale value of bitrate and initial delay

int EncHRD::xCalcScale(uint32_t x)

{

  if (x==0)

  {

    return 0;

  }

  uint32_t mask = 0xffffffff;

  int scaleValue = 32;

  while ((x&mask) != 0)

  {

    scaleValue--;

    mask = (mask >> 1);

  }

  return scaleValue;

}

void EncHRD::initHRDParameters(const VVEncCfg& encCfg, const SPS& sps)

{

//  if (!encCfg.m_hrdParametersPresent && !encCfg.getCpbSaturationEnabled())

//  {

//    return;

//  }

  ProfileLevelTierFeatures profileLevelTierFeatures;

  profileLevelTierFeatures.extractPTLInformation( sps );

  bool useSubCpbParams = false; //encCfg.getNoPicPartitionFlag() == false;

  uint32_t bitRate = (uint32_t)encCfg.m_RCTargetBitrate;

  uint32_t cpbSize = (uint32_t)profileLevelTierFeatures.getCpbSizeInBits();

  CHECK(!(cpbSize != 0), "Unspecified error");  // CPB size may not be equal to zero. ToDo: have a better default and check for level constraints

  generalHrdParams.timeScale      = encCfg.m_FrameRate;

  generalHrdParams.numUnitsInTick = encCfg.m_FrameScale;

  bool rateCnt = (bitRate > 0);

  generalHrdParams.generalNalHrdParamsPresent = rateCnt;

  generalHrdParams.generalVclHrdParamsPresent = rateCnt;

  generalHrdParams.generalSamePicTimingInAllOlsFlag = true;

  useSubCpbParams &= (generalHrdParams.generalNalHrdParamsPresent || generalHrdParams.generalVclHrdParamsPresent);

  generalHrdParams.generalDecodingUnitHrdParamsPresent = useSubCpbParams;

  if (generalHrdParams.generalDecodingUnitHrdParamsPresent)

  {

    generalHrdParams.tickDivisorMinus2 = (100 - 2);

  }

  if (xCalcScale(bitRate) <= 6)

  {

    generalHrdParams.bitRateScale = 0;

  }

  else

  {

    generalHrdParams.bitRateScale = xCalcScale(bitRate) - 6;

  }

  if (xCalcScale(cpbSize) <= 4)

  {

    generalHrdParams.cpbSizeScale = 0;

  }

  else

  {

    generalHrdParams.cpbSizeScale = xCalcScale(cpbSize) - 4;

  }

  generalHrdParams.cpbSizeDuScale = 6;                                     // in units of 2^( 4 + 6 ) = 1,024 bit

  generalHrdParams.hrdCpbCntMinus1 = 0;

  // Note: parameters for all temporal layers are initialized with the same values

  int i, j;

  uint32_t bitrateValue, cpbSizeValue;

  uint32_t duCpbSizeValue;

  uint32_t duBitRateValue = 0;

  for (i = 0; i < VVENC_MAX_TLAYER; i++)

  {

    olsHrdParams[i].fixedPicRateGeneralFlag = true;

    olsHrdParams[i].fixedPicRateWithinCvsFlag = true;

    olsHrdParams[i].elementDurationInTcMinus1 = 0;

    olsHrdParams[i].lowDelayHrdFlag = false;

    //! \todo check for possible PTL violations

    // BitRate[ i ] = ( bit_rate_value_minus1[ i ] + 1 ) * 2^( 6 + bit_rate_scale )

    bitrateValue = bitRate / (1 << (6 + generalHrdParams.bitRateScale));      // bitRate is in bits, so it needs to be scaled down

                                                                              // CpbSize[ i ] = ( cpb_size_value_minus1[ i ] + 1 ) * 2^( 4 + cpb_size_scale )

    cpbSizeValue = cpbSize / (1 << (4 + generalHrdParams.cpbSizeScale));      // using bitRate results in 1 second CPB size

                                                                              // DU CPB size could be smaller (i.e. bitrateValue / number of DUs), but we don't know

                                                                              // in how many DUs the slice segment settings will result

    duCpbSizeValue = bitrateValue;

    duBitRateValue = cpbSizeValue;

    for (j = 0; j < (generalHrdParams.hrdCpbCntMinus1 + 1); j++)

    {

      olsHrdParams[i].bitRateValueMinus1[j][0] =  bitrateValue - 1;

      olsHrdParams[i].cpbSizeValueMinus1[j][0] =  cpbSizeValue - 1;

      olsHrdParams[i].duCpbSizeValueMinus1[j][0] =  duCpbSizeValue - 1;

      olsHrdParams[i].duBitRateValueMinus1[j][0] =  duBitRateValue - 1;

      olsHrdParams[i].cbrFlag[j][0] =  false;

      olsHrdParams[i].bitRateValueMinus1[j][1] =  bitrateValue - 1;

      olsHrdParams[i].cpbSizeValueMinus1[j][1] =  cpbSizeValue - 1;

      olsHrdParams[i].duCpbSizeValueMinus1[j][1] =  duCpbSizeValue - 1;

      olsHrdParams[i].duBitRateValueMinus1[j][1] =  duBitRateValue - 1;

      olsHrdParams[i].cbrFlag[j][1] =  false;

    }

  }

}

} //namespace