Class: MusicMaster::Processes::Compressor

Inherits:
Object
  • Object
show all
Includes:
WSK::Common
Defined in:
lib/MusicMaster/Processes/Compressor.rb

Constant Summary collapse

MINUS_INFINITY =

-Infinity

-1.0/0.0
PROFILEVOLUME_INTERVAL =

Interval used to profile the volume

'0.1s'

Instance Method Summary collapse

Instance Method Details

#dumpDebugFct(iInputFileName, iFunction, iName, iDBUnits, iTempDir) ⇒ Object

Dump a function into a Wave file. This is used for debugging purposes only.

Parameters

  • iInputFileName (String): Name of the input file

  • iFunction (WSK::Functions::Function): The function to dump

  • iName (String): Name given to this function

  • iDBUnits (Boolean): Is the function in DB units ?

  • iTempDir (String): Temporary directory to use



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# File 'lib/MusicMaster/Processes/Compressor.rb', line 236

def dumpDebugFct(iInputFileName, iFunction, iName, iDBUnits, iTempDir)
  lBaseFileName = File.basename(iInputFileName)[0..-5]
  # Clone the function to round it first
  lRoundedFunction = WSK::Functions::Function.new
  lRoundedFunction.set(iFunction.function_data.clone)
  lRoundedFunction.write_to_file("#{iTempDir}/_#{lBaseFileName}_#{iName}.fct.rb", :Floats => true)
  wsk(iInputFileName, "#{iTempDir}/_#{lBaseFileName}_#{iName}.wav", 'DrawFct', "--function \"#{iTempDir}/_#{lBaseFileName}_#{iName}.fct.rb\" --unitdb #{iDBUnits ? '1' : '0'}")
end

#execute(iInputFileName, iOutputFileName, iTempDir, iParams) ⇒ Object

Execute the process

Parameters

  • iInputFileName (String): File name we want to apply effects to

  • iOutputFileName (String): File name to write

  • iTempDir (String): Temporary directory that can be used

  • iParams (map<Symbol,Object>): Parameters



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# File 'lib/MusicMaster/Processes/Compressor.rb', line 42

def execute(iInputFileName, iOutputFileName, iTempDir, iParams)
  # Check parameters
  lDBUnits = iParams[:DBUnits]
  if (lDBUnits == nil)
    lDBUnits = false
  end
  lParamsOK = true
  if (lDBUnits)
    # Threshold must be < 0
    if (iParams[:Threshold] >= 0)
      log_err "Threshold (#{iParams[:Threshold]}db) has to be < 0db"
      lParamsOK = false
    end
  else
    # Threshold must be < 1
    if (iParams[:Threshold] >= 1)
      log_err "Threshold (#{iParams[:Threshold]}) has to be < 1"
      lParamsOK = false
    end
    # Threshold must be > 0
    if (iParams[:Threshold] <= 0)
      log_err "Threshold (#{iParams[:Threshold]}) has to be > 0"
      lParamsOK = false
    end
  end
  # Ratio must be > 1
  if (iParams[:Ratio] <= 1)
    log_err "Ratio (#{iParams[:Ratio]}) has to be > 1"
    lParamsOK = false
  end
  if (lParamsOK)
    # Get the volume profile of the Wave file
    lTempVolProfileFile = "#{iTempDir}/#{File.basename(iInputFileName)[0..-5]}.ProfileFct.rb"
    if (File.exists?(lTempVolProfileFile))
      log_warn "File #{lTempVolProfileFile} already exists. Will not overwrite it."
    else
      lTempWaveFile = "#{iTempDir}/Dummy.wav"
      # Get the volume profile
      wsk(iInputFileName, lTempWaveFile, 'VolumeProfile', "--function \"#{lTempVolProfileFile}\" --begin 0 --end -1 --interval \"#{PROFILEVOLUME_INTERVAL}\" --rmsratio #{iParams[:RMSRatio]}")
      File::unlink(lTempWaveFile)
    end

    # Get the file header for various measures later
    lHeader = nil
    File.open(iInputFileName, 'rb') do |iFile|
      lError, lHeader = readHeader(iFile)
      if (lError != nil)
        log_err "An error occurred while reading header: #{lError}"
      end
    end

    # Create the Compressor's function based on the parameters
    # Minimal value represented in DB.
    # This value will be used to replace -Infinity
    lMinimalDBValue = nil
    lCompressorFunction = WSK::Functions::Function.new
    lBDThreshold = iParams[:Threshold].to_r
    if (lDBUnits)
      # The minimal DB value is the smallest ratio possible for RMS values of this file (1/2^(BPS-1)) converted in DB and minus 1 to not mix it with the ratio 1/2^(BPS-1)
      lMinimalDBValue = lCompressorFunction.value_val_2_db(Rational(1), Rational(2)**(lHeader.NbrBitsPerSample-1)) - 1
      lCompressorFunction.set( {
        :FunctionType => WSK::Functions::FCTTYPE_PIECEWISE_LINEAR,
        :Points => [
          [lMinimalDBValue, lMinimalDBValue],
          [lBDThreshold, lBDThreshold],
          [0, lBDThreshold - lBDThreshold/(iParams[:Ratio].to_r) ]
        ]
      } )
    else
      lCompressorFunction.set( {
        :FunctionType => WSK::Functions::FCTTYPE_PIECEWISE_LINEAR,
        :Points => [
          [0, 0],
          [lBDThreshold, lBDThreshold],
          [1, lBDThreshold + (1-lBDThreshold)/(iParams[:Ratio].to_r) ]
        ]
      } )
    end
    log_info "Compressor transfer function: #{lCompressorFunction.function_data[:Points].map{ |p| next [ sprintf('%.2f', p[0]), sprintf('%.2f', p[1]) ] }.inspect}"

    # Compute the volume transformation function based on the profile function and the Compressor's parameters
    lTempVolTransformFile = "#{iTempDir}/#{File.basename(iInputFileName)[0..-5]}.VolumeFct.rb"
    if (File.exists?(lTempVolTransformFile))
      log_warn "File #{lTempVolTransformFile} already exists. Will not overwrite it."
    else
      # Read the Profile function
      log_info 'Create volume profile function ...'
      lProfileFunction = WSK::Functions::Function.new
      lProfileFunction.read_from_file(lTempVolProfileFile)
      if (lDBUnits)
        # Convert the Profile function in DB units
        lProfileFunction.convert_to_db(Rational(1))
        # Replace -Infinity with lMinimalDBValue
        lProfileFunction.function_data[:Points].each do |ioPoint|
          if (ioPoint[1] == MINUS_INFINITY)
            ioPoint[1] = lMinimalDBValue
          end
        end
      end
      
      #dumpDebugFct(iInputFileName, lProfileFunction, 'ProfileDB', lDBUnits, iTempDir)

      # Clone the profile function before applying the map
      lNewProfileFunction = WSK::Functions::Function.new
      lNewProfileFunction.set(lProfileFunction.function_data.clone)
      
      # Transform the Profile function with the Compressor function
      log_info 'Apply compressor transfer function ...'
      lNewProfileFunction.apply_map_function(lCompressorFunction)

      #dumpDebugFct(iInputFileName, lNewProfileFunction, 'NewProfileDB', lDBUnits, iTempDir)

      # The difference of the functions will give the volume transformation profile
      log_info 'Compute differing function ...'
      lDiffProfileFunction = WSK::Functions::Function.new
      lDiffProfileFunction.set(lNewProfileFunction.function_data.clone)
      if (lDBUnits)
        # The volume transformation will be a DB difference
        lDiffProfileFunction.substract_function(lProfileFunction)
      else
        # The volume transformation will be a ratio
        lDiffProfileFunction.divide_by_function(lProfileFunction)
      end

      dumpDebugFct(iInputFileName, lDiffProfileFunction, 'RawDiffProfileDB', lDBUnits, iTempDir)

      # Apply damping for attack and release times
      log_info 'Damp differing function with attack and release ...'
      lAttackDuration = Rational(readDuration(iParams[:AttackDuration], lHeader.SampleRate))
      lAttackSlope = iParams[:AttackDamping].to_f.to_r/lAttackDuration
      lReleaseDuration = Rational(readDuration(iParams[:ReleaseDuration], lHeader.SampleRate))
      lReleaseSlope = iParams[:ReleaseDamping].to_f.to_r/lReleaseDuration
      if (lDBUnits)
        lAttackSlope = -lAttackSlope
        lReleaseSlope = -lReleaseSlope
      end
      # Take care of look-aheads
      if ((iParams[:AttackLookAhead] == true) or
          (iParams[:ReleaseLookAhead] == true))
        # Look-Aheads are implemented by applying damping on the reverted function
        lDiffProfileFunction.invert_abscisses
        if (iParams[:AttackLookAhead] == false)
          lDiffProfileFunction.apply_damping(nil, -lReleaseSlope)
        elsif (iParams[:ReleaseLookAhead] == false)
          lDiffProfileFunction.apply_damping(lAttackSlope, nil)
        else
          lDiffProfileFunction.apply_damping(lAttackSlope, -lReleaseSlope)
        end
        lDiffProfileFunction.invert_abscisses
      end
      if (iParams[:AttackLookAhead] == true)
        if (iParams[:ReleaseLookAhead] == false)
          lDiffProfileFunction.apply_damping(lReleaseSlope, nil)
        end
      elsif (iParams[:ReleaseLookAhead] == true)
        if (iParams[:AttackLookAhead] == false)
          lDiffProfileFunction.apply_damping(nil, -lAttackSlope)
        end
      else
        lDiffProfileFunction.apply_damping(lReleaseSlope, -lAttackSlope)
      end
      
      #dumpDebugFct(iInputFileName, lDiffProfileFunction, 'DampedDiffProfileDB', lDBUnits, iTempDir)
      
      # Eliminate glitches in the function.
      # This is done by deleting intermediate abscisses that are too close to each other

      log_info 'Smooth differing function ...'
      lDiffProfileFunction.remove_noise_abscisses(Rational(readDuration(iParams[:MinChangeDuration], lHeader.SampleRate)))

      dumpDebugFct(iInputFileName, lDiffProfileFunction, 'SmoothedDiffProfileDB', lDBUnits, iTempDir)

      # Save the volume transformation file
      lDiffProfileFunction.write_to_file(lTempVolTransformFile)
    end

    # Apply the volume transformation to the Wave file
    lStrUnitDB = 0
    if (lDBUnits)
      lStrUnitDB = 1
    end
    wsk(iInputFileName, iOutputFileName, 'ApplyVolumeFct', "--function \"#{lTempVolTransformFile}\" --begin 0 --end -1 --unitdb #{lStrUnitDB}")
  end
end