AnnexBwrite.h

/* The copyright in this software is being made available under the BSD
 * License, included below. This software may be subject to other third party
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 * granted under this license.
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 * Copyright (c) 2010-2023, ITU/ISO/IEC
 * All rights reserved.
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 * modification, are permitted provided that the following conditions are met:
 *
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 *    this list of conditions and the following disclaimer.
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 *    be used to endorse or promote products derived from this software without
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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 */

#pragma once

#ifndef __ANNEXBWRITE__
#define __ANNEXBWRITE__

#include <ostream>
#include "NALwrite.h"

//! \ingroup EncoderLib
//! \{

void checkWriteError(std::ostream& out)
{
  if (out.fail())
  {
    printf ("Error writing bitstream file\n");
    exit (EXIT_FAILURE);
  }
}

uint32_t writeAnnexBNalUnit(std::ostream& out, const NALUnitEBSP& nalu, bool useLongStartcode)
{
  uint32_t size = 0; /* size of annexB unit in bytes */

  static const uint8_t startCodePrefix[] = {0,0,0,1};

  if (useLongStartcode)
  {
    out.write(reinterpret_cast<const char*>(startCodePrefix), 4);
    checkWriteError(out);
    size += 4;
  }
  else
  {
    out.write(reinterpret_cast<const char*>(startCodePrefix+1), 3);
    checkWriteError(out);
    size += 3;
  }
  out << nalu.m_nalUnitData.str();
  checkWriteError(out);
  size += uint32_t(nalu.m_nalUnitData.str().size());

  return size;
}

/**
 * write all NALunits in au to bytestream out in a manner satisfying
 * AnnexB of AVC.  NALunits are written in the order they are found in au.
 * the zero_byte word is appended to:
 *  - the initial startcode in the access unit,
 *  - any SPS/PPS nal units
 */
std::vector<uint32_t> writeAnnexBAccessUnit(std::ostream& out, const AccessUnit& au)
{
  std::vector<uint32_t> annexBsizes;

  for (AccessUnit::const_iterator it = au.begin(); it != au.end(); it++)
  {
    const NALUnitEBSP& nalu = **it;
    const bool useLongStartCode = (it == au.begin() || nalu.m_nalUnitType == NAL_UNIT_OPI || nalu.m_nalUnitType == NAL_UNIT_DCI || nalu.m_nalUnitType == NAL_UNIT_VPS || nalu.m_nalUnitType == NAL_UNIT_SPS
                                   || nalu.m_nalUnitType == NAL_UNIT_PPS || nalu.m_nalUnitType == NAL_UNIT_PREFIX_APS || nalu.m_nalUnitType == NAL_UNIT_SUFFIX_APS);

    const uint32_t size = writeAnnexBNalUnit(out, nalu, useLongStartCode);

    annexBsizes.push_back(size);
  }

  if (au.size() > 0)
  {
    out.flush();
  }

  return annexBsizes;
}

//! \}

#endif