source: 3DVCSoftware/branches/HTM-DEV-2.0-dev3-Samsung/source/App/utils/BitrateTargeting/ExtractBitrates.cpp

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 * granted under this license.  
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 * Copyright (c) 2010-2012, ITU/ISO/IEC
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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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#include "ExtractBitrates.h"
#include <string>
#include <sstream>
#include <cassert>
#include <limits>
#include <map>

namespace
{
  /// Maintains a sum and a sample-count for calculating averages
  class Tally
  {
    public:
      
      /// Contructs a new zeroed tally
      Tally( ): m_sum( 0.0 ), m_numSlices( 0 ) { }
      
      /// Adds to the sum and increments the sample-count
      void add( double in ) { ++m_numSlices; m_sum += in; }
      
      /// \return The calculated average
      double average( ) const { return m_sum / ( double )m_numSlices; }
    
    private:
      double m_sum;
      unsigned long m_numSlices;
  };
  
  /// Ignores all of the the characters up to and including a given character
  /// \param line The line being read from
  /// \param iLine The active input stream
  /// \param character The character to ignore up to
  /// \throw POCParseException if the stream goes bad before character is encountered or just after character is encountered
  void ignoreUpTo( const std::string& line, std::istream& iLine, char character )
  {
    while( iLine.good( ) && character != iLine.get( ) )
      ;
    if( !iLine.good( ) ) throw POCParseException( line );
  }
  
  /// Extracts the average bitrates for each of the temporal layers from the given log
  /// \param i The input stream that represents the log
  /// \return A map that countains the average bitrates for each temporal layer.  Each pair contains the QP value in first and the average bitrate in second.
  /// \throw POCParseException if an error occured while parsing a POC line
  std::map< unsigned char, double > extractBitratesForQPs( std::istream& i )
  {
    std::map< unsigned char, Tally > tallyMap;
    
    while( i.good( ) )
    {
      // Initialize variables for this line
      std::string line;
      std::getline( i, line );
      std::istringstream iLine( line );
      if( !iLine.good( ) ) continue;
      
      // Ignore the "POC"
      if( iLine.get( ) != 'P' ) continue;
      if( !iLine.good( ) ) continue;
      if( iLine.get( ) != 'O' ) continue;
      if( !iLine.good( ) ) continue;
      if( iLine.get( ) != 'C' ) continue;
      if( !iLine.good( ) ) throw POCParseException( line );
      
      ignoreUpTo( line, iLine, '(' );
      
      if( iLine.get( ) != ' ' ) throw POCParseException( line );
      if( !iLine.good( ) ) throw POCParseException( line );
      
      if( 'I' == iLine.get( ) ) continue;
      if( !iLine.good( ) ) throw POCParseException( line );
      
      ignoreUpTo( line, iLine, ' ' );
      ignoreUpTo( line, iLine, ' ' );
      
      // Parse the qpIndex
      long qpIndexLong;
      iLine >> qpIndexLong;
      if( ( long )std::numeric_limits< unsigned char >::max( ) < qpIndexLong ) throw POCParseException( line );
      unsigned char qpIndex( ( unsigned char )qpIndexLong );
      if( !iLine.good( ) ) throw POCParseException( line );
      
      ignoreUpTo( line, iLine, ')' );
      ignoreUpTo( line, iLine, ' ' );
      
      // Parse the number of bits
      unsigned long bitsULong;
      iLine >> bitsULong;
      if( !iLine.good( ) ) throw POCParseException( line );
      
      // Find the tally that corresponds to our QP.  If there is no such tally yet, then add a new one to the map.
      std::map< unsigned char, Tally >::iterator iter( tallyMap.find( qpIndex ) );
      if( tallyMap.end( ) == iter )
      {
        tallyMap[ qpIndex ] = Tally( );
        iter = tallyMap.find( qpIndex );
      }
      assert( iter != tallyMap.end( ) );
      
      iter->second.add( ( double )bitsULong );
    }
    
    // Populate and return the result based on all of the tallies
    std::map< unsigned char, double > result;
    for( std::map< unsigned char, Tally >::const_iterator iter( tallyMap.begin( ) ); iter != tallyMap.end( ); ++iter )
    {
      result[ iter->first ] = iter->second.average( );
    }
    return result;
  }
}

std::vector< double > extractBitratesForTemporalLayers( std::istream& i )
{
  std::vector< double > result;
  
  std::map< unsigned char, double > bitratesForQPsMap( extractBitratesForQPs( i ) );
  if( !bitratesForQPsMap.empty( ) )
  {
    unsigned char expectedNextQPIndex( bitratesForQPsMap.begin( )->first );
    
    for( std::map< unsigned char, double >::const_iterator i( bitratesForQPsMap.begin( ) ); i != bitratesForQPsMap.end( ); ++i )
    {
      if( i->first != expectedNextQPIndex ) throw NonContiguousQPSetException( );
      ++expectedNextQPIndex;
      result.push_back( i->second );
    }
  }
  
  return result;
}