Method getSeekData

YUViewLib/src/parser/AVC/ParserAnnexBAVC.cpp:579–642

}

std::optional<ParserAnnexB::SeekData> ParserAnnexBAVC::getSeekData(int iFrameNr)
{
  if (iFrameNr >= int(this->getNumberPOCs()) || iFrameNr < 0)
    return {};

  auto seekPOC = this->getFramePOC(unsigned(iFrameNr));

  // Collect the active parameter sets
  using NalMap = std::map<unsigned, std::shared_ptr<NalUnitAVC>>;
  NalMap activeSPSNal;
  NalMap activePPSNal;

  for (auto nal : this->nalUnitsForSeeking)
  {
    if (nal->header.nal_unit_type == NalType::CODED_SLICE_IDR ||
        nal->header.nal_unit_type == NalType::CODED_SLICE_NON_IDR ||
        nal->header.nal_unit_type == NalType::CODED_SLICE_DATA_PARTITION_A)
    {
      int globalPOC{};
      if (nal->header.nal_unit_type == NalType::CODED_SLICE_IDR ||
          nal->header.nal_unit_type == NalType::CODED_SLICE_NON_IDR)
      {
        auto slice = std::dynamic_pointer_cast<slice_layer_without_partitioning_rbsp>(nal->rbsp);
        globalPOC  = slice->sliceHeader->globalPOC;
      }
      else if (nal->header.nal_unit_type == NalType::CODED_SLICE_DATA_PARTITION_A)
      {
        auto slice = std::dynamic_pointer_cast<slice_data_partition_a_layer_rbsp>(nal->rbsp);
        globalPOC  = slice->sliceHeader->globalPOC;
      }

      if (globalPOC == seekPOC)
      {
        // Seek here
        ParserAnnexB::SeekData seekData;
        if (nal->filePosStartEnd)
          seekData.filePos = nal->filePosStartEnd->first;

        // Get the bitstream of all active parameter sets
        for (const auto &nalMap : {activeSPSNal, activePPSNal})
        {
          for (auto const &entry : nalMap)
            seekData.parameterSets.push_back(entry.second->rawData);
        }

        return seekData;
      }
    }
    else if (nal->header.nal_unit_type == NalType::SPS)
    {
      // Add sps (replace old one if existed)
      auto sps = std::dynamic_pointer_cast<seq_parameter_set_rbsp>(nal->rbsp);
      activeSPSNal[sps->seqParameterSetData.seq_parameter_set_id] = nal;
    }
    else if (nal->header.nal_unit_type == NalType::PPS)
    {
      // Add pps (replace old one if existed)
      auto pps = std::dynamic_pointer_cast<pic_parameter_set_rbsp>(nal->rbsp);