Class: MeanFast

Inherits:
Object
  • Object
show all
Defined in:
lib/Loudness/Mean/MeanFast.rb

Overview

Conputes mean

Defined Under Namespace

Modules: MEAN_MODE

Instance Method Summary collapse

Constructor Details

#initialize ⇒ MeanFast

Returns a new instance of MeanFast.



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# File 'lib/Loudness/Mean/MeanFast.rb', line 14

def initialize
  @bIni = false
  @mode = MEAN_MODE::MEAN_TOTAL

  #Vars used in Overlapped mode
  @lSamplesInInterval = 0
  @lSamplesOverlapped = 0
  @lGetMeanEveryXSamples = 0
  @nSums = 0
  @Sums  = 0
  @lNumSamplesLoaded = 0
  @nSumIndex = 0    
  @queueMean = Array.new
  
  #Vars used in TOTAL mode
  @lNumAcumulatedSamplesMean = 0
  @dAccumulatedMean = 0.0
  
  #if @mode == MEAN_MODE::MEAN_TOTAL the fs, lMeanIntervalms, dOverlappingFactor does not take effect
  Ini(@mode, 48000, 400, 0.75)
end

Instance Method Details

#AddSample(dSample) ⇒ Object

Adds a new sample to mean computation

Parameters:

  • dSample (Float) —

    new sample



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# File 'lib/Loudness/Mean/MeanFast.rb', line 77

def AddSample (dSample)
  rc = false
  
  if (@mode == MEAN_MODE::MEAN_OVERLAPPED)
    ni = 0     
    while ni < @nSums do
      @Sums[ni] = @Sums[ni].to_f + (dSample.to_f * dSample.to_f)
      
      ni = ni + 1
    end 
    
    @lNumSamplesLoaded = @lNumSamplesLoaded + 1

    if ((@lNumSamplesLoaded % @lGetMeanEveryXSamples) == 0)
      dMean = @Sums[@nSumIndex].to_f / @lSamplesInInterval.to_f
      
      @queueMean.insert(-1, dMean) #Insert at loast position
      
      rc = true
      @Sums[@nSumIndex] = 0.0

      @nSumIndex = @nSumIndex + 1        
      if (@nSumIndex >= @nSums)
        @nSumIndex = 0
      end
    end
    
    if (@lNumSamplesLoaded >= @lSamplesInInterval)
      @lNumSamplesLoaded = 0
    end        
  else
    dAddVal = dSample.to_f * dSample.to_f

    if (@lNumAcumulatedSamplesMean > 0)
      dMul = @lNumAcumulatedSamplesMean.to_f / (@lNumAcumulatedSamplesMean + 1).to_f
      @dAccumulatedMean = (@dAccumulatedMean.to_f * dMul.to_f) + dAddVal.to_f / (@lNumAcumulatedSamplesMean + 1).to_f
    else
      @dAccumulatedMean = dAddVal
    end
    @lNumAcumulatedSamplesMean = @lNumAcumulatedSamplesMean + 1

    rc = true      
  end
  
  return rc
end

#GetMeanVal ⇒ Float

Adds a new sample to mean computation

Returns:

  • (Float) —

    the resulting mean value



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# File 'lib/Loudness/Mean/MeanFast.rb', line 126

def GetMeanVal
  if (@mode == MEAN_MODE::MEAN_OVERLAPPED)
    raise 'ERROR function not valid in overlapped mean mode'
  end
  
  return @dAccumulatedMean
end

#Ini(mode, fs = 0, lMeanIntervalms = 0, dOverlappingFactor = 0) ⇒ Object

Initializes the mean computation, and it sets the mean mode

Parameters:

  • mode —

    Must be = MEAN_TOTAL

  • fs (int) (defaults to: 0) —

    not used in this version

  • lMeanIntervalms (int) (defaults to: 0) —

    not used in this version

  • dOverlappingFactor (Float) (defaults to: 0) —

    not used in this version



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# File 'lib/Loudness/Mean/MeanFast.rb', line 41

def Ini(mode, fs = 0, lMeanIntervalms = 0, dOverlappingFactor = 0)    
  
  if (@bIni == true)
    raise 'ERROR bad state'
  end
  
  if (fs <= 0) or (lMeanIntervalms <= 0) or (dOverlappingFactor <= 0.0) or (dOverlappingFactor >= 1.0)        
    raise 'ERROR bad arguments'
  end
  
  @mode = mode
  
  if (@mode == MEAN_MODE::MEAN_OVERLAPPED)
    @lSamplesInInterval = Integer(fs.to_f * (lMeanIntervalms.to_f / 1000.0))
    @lSamplesOverlapped = Integer(@lSamplesInInterval.to_f * dOverlappingFactor.to_f)
    @lGetMeanEveryXSamples = @lSamplesInInterval - @lSamplesOverlapped;

    if (@lGetMeanEveryXSamples <= 0)
      raise 'ERROR calculating lGetMeanEveryXSamples (bad arguments)'
    end
    
    @nSums = @lSamplesInInterval / @lGetMeanEveryXSamples; 
    @Sums = Array.new(@nSums) {|i| i = 0}

    @lNumSamplesLoaded = 0;
    @nSumIndex = 0;  
  else  
    @lNumAcumulatedSamplesMean = 0;
    @dAccumulatedMean = 0.0;
  end

  @bIni = true;
end