Class: WavFile

Inherits:
Object
  • Object
show all
Defined in:
lib/wav.rb

Overview

WAV file parser

Copyright (C) 2014 Hiroshi Kuwagata <[email protected]>

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file) ⇒ WavFile

Returns a new instance of WavFile.



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# File 'lib/wav.rb', line 15

def initialize(file)
  @io = File.open(file, "rb")
  
  tmp = @io.read(12).unpack('a4Va4')

  @magic         = tmp[0]
  @data_size     = tmp[1]
  @type          = tmp[2]

  if not (@magic == "RIFF" and @type == "WAVE")
    raise('Illeagal magic number.')
  end

  if @data_size != (File.size(file) - 8)
    raise('Data size is not match.')
  end

  tmp = @io.read(8).unpack('a4V')

  @id            = tmp[0]

  if @id != 'fmt '
    raise('ID "%s" is not supported.' % @id)
  end

  tmp = @io.read(tmp[1]).unpack('vvVVvv')

  @format_id     = tmp[0]
  @channel_num   = tmp[1]
  @sample_rate   = tmp[2]
  @bytes_per_sec = tmp[3]
  @block_size    = tmp[4]
  @sample_size   = tmp[5]

  loop {
    tmp = @io.read(8).unpack('a4V')
    break if tmp[0] == "data"

    @io.seek(tmp[1], IO::SEEK_CUR)
  }

  @data_offset   = @io.pos
  @data_size     = tmp[1]
end

Instance Attribute Details

#block_size ⇒ Object (readonly)

Returns the value of attribute block_size.



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# File 'lib/wav.rb', line 60

def block_size
  @block_size
end

#bytes_per_sec ⇒ Object (readonly)

Returns the value of attribute bytes_per_sec.



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# File 'lib/wav.rb', line 60

def bytes_per_sec
  @bytes_per_sec
end

#channel_num ⇒ Object (readonly)

Returns the value of attribute channel_num.



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# File 'lib/wav.rb', line 60

def channel_num
  @channel_num
end

#data_size ⇒ Object (readonly)

Returns the value of attribute data_size.



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# File 'lib/wav.rb', line 60

def data_size
  @data_size
end

#sample_rate ⇒ Object (readonly)

Returns the value of attribute sample_rate.



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# File 'lib/wav.rb', line 60

def sample_rate
  @sample_rate
end

#sample_size ⇒ Object (readonly)

Returns the value of attribute sample_size.



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# File 'lib/wav.rb', line 60

def sample_size
  @sample_size
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/wav.rb', line 79

def close
  @io.close
end

#eof? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/wav.rb', line 75

def eof?
  @io.eof?
end

#read(n = nil) ⇒ Object 



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# File 'lib/wav.rb', line 63

def read(n = nil)
  if not n.nil?
    @io.read(@block_size * n)
  else
    @io.read
  end
end

#seek(pos) ⇒ Object 



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# File 'lib/wav.rb', line 71

def seek(pos)
  @io.seek(@block_size * pos, IO::SEEK_SET)
end