Class: AudioStream::Fx::ConvolutionReverb

Inherits:
Object
  • Object
show all
Defined in:
lib/audio_stream/fx/convolution_reverb.rb

Instance Method Summary collapse

Constructor Details

#initialize(impulse, dry: -6,, wet: -6)) ⇒ ConvolutionReverb

Returns a new instance of ConvolutionReverb.

Parameters:



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# File 'lib/audio_stream/fx/convolution_reverb.rb', line 7

def initialize(impulse, dry: -6, wet: -6)
  impulse_bufs = impulse.to_a
  @impulse_size = impulse_bufs.size
  @channels = impulse_bufs[0].channels
  @window_size = impulse_bufs[0].window_size
  @dry_gain = Decibel.db(dry).mag
  @wet_gain = Decibel.db(wet).mag

  zero_buf = Buffer.create(@window_size, @channels)
  impulse_bufs = [zero_buf.clone] + impulse_bufs

  @impulse_ffts = []
  @impulse_size.times {|i|
    na = NArray.float(@channels, @window_size*2)
    impulse_bufs[i].to_float_na(na, 0)
    impulse_bufs[i+1].to_float_na(na, @window_size*@channels)
    @impulse_ffts << FFTW3.fft(na, FFTW3::FORWARD) / na.length
  }

  @impulse_max_gain =  @impulse_ffts.map{|c| c.real**2 + c.imag**2}.map(&:sum).max / @channels

  @wet_ffts = RingBuffer.new(@impulse_size) {
    Array.new(@impulse_size, NArray.float(@channels, @window_size*2))
  }

  @prev_input = zero_buf.clone
end

Instance Method Details

#process(input) ⇒ Object 



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# File 'lib/audio_stream/fx/convolution_reverb.rb', line 35

def process(input)
  if @window_size!=input.window_size
    raise "window size is not match: impulse.size=#{@window_size} input.size=#{input.window_size}"
  end
  if @channels!=input.channels
    raise "channels is not match: impulse.channels=#{@channels} input.channels=#{input.channels}"
  end

  # current dry to wet
  na = NArray.float(@channels, @window_size*2)
  @prev_input.to_float_na(na, 0)
  input.to_float_na(na, @window_size*@channels)

  input_fft = FFTW3.fft(na, FFTW3::FORWARD) / na.length

  @wet_ffts.current = @impulse_ffts.map {|impulse_fft|
    input_fft * impulse_fft
  }
  @wet_ffts.rotate
  @prev_input = input.clone

  # calc wet matrix sum
  wet_fft = NArray.complex(@channels, @window_size*2)
  @wet_ffts.each_with_index {|wet, i|
    wet_fft += wet[@impulse_size-i-1]
  }

  wet_na = FFTW3.fft(wet_fft, FFTW3::BACKWARD)[(@channels*@window_size)...(@channels*@window_size*2)] * (@wet_gain / @impulse_max_gain)

  # current dry + wet matrix sum
  src0 = input.streams[0]
  src1 = input.streams[1]

  case @channels
  when 1
    output = Buffer.create_mono(@window_size)
    dst0 = output.streams[0]

    @window_size.times {|i|
      dry = src0[i] * @dry_gain
      wet = wet_na[i].real
      dst0[i] = dry + wet
    }
  when 2
    output = Buffer.create_stereo(@window_size)
    dst0 = output.streams[0]
    dst1 = output.streams[1]

    @window_size.times {|i|
      # dry
      dry0 = src0[i] * @dry_gain
      dry1 = src1[i] * @dry_gain

      # wet
      wet0 = wet_na[i*2].real
      wet1 = wet_na[(i*2)+1].real

      dst0[i] = dry0 + wet0
      dst1[i] = dry1 + wet1
    }
  end

  output
end