Class: NuWav::WaveFile

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

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ WaveFile

Returns a new instance of WaveFile.



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# File 'lib/nu_wav/wave_file.rb', line 11

def initialize
  self.chunks = {}
end

Instance Attribute Details

#chunks ⇒ Object

Returns the value of attribute chunks.



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# File 'lib/nu_wav/wave_file.rb', line 5

def chunks
  @chunks
end

#header ⇒ Object

Returns the value of attribute header.



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# File 'lib/nu_wav/wave_file.rb', line 5

def header
  @header
end

Class Method Details

.calculate_mpeg_frame_size(info) ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 245

def self.calculate_mpeg_frame_size(info)
  samples_per_frame = Mp3Info::SAMPLES_PER_FRAME[info.layer][info.mpeg_version]
  ((samples_per_frame / 8) * (info.bitrate * 1000))/info.samplerate
end

.calculate_mpeg_head_flags(info) ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 235

def self.calculate_mpeg_head_flags(info)
  flags = 0
  flags += 1 if (info.header[:private_bit])
  flags += 2 if (info.header[:copyright])
  flags += 4 if (info.header[:original])
  flags += 8 if (info.header[:error_protection])
  flags += 16 if (info.mpeg_version > 0)
  flags
end

.calculate_mpeg_samples_number(file, info) ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 231

def self.calculate_mpeg_samples_number(file, info)
  (File.size(file.path) / calculate_mpeg_frame_size(info)) * Mp3Info::SAMPLES_PER_FRAME[info.layer][info.mpeg_version]
end

.from_mpeg(file_name) ⇒ Object

method to create a wave file using the



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# File 'lib/nu_wav/wave_file.rb', line 151

def self.from_mpeg(file_name)
  # read and display infos & tags
  NuWav::WaveFile.log "NuWav::from_mpeg::file_name:#{file_name}"
  mp3info = Mp3Info.open(file_name)
  NuWav::WaveFile.log mp3info
  file = File.open(file_name)
  wave = WaveFile.new
  
  # data chunk
  data = DataChunk.new_from_file(file)
  wave.chunks[:data] = data

  # fmt chunk
  fmt = FmtChunk.new
  fmt.compression_code = MPEG_COMPRESSION
  fmt.number_of_channels = (mp3info.channel_mode == "Single Channel") ? 1 : 2
  fmt.sample_rate = mp3info.samplerate
  fmt.byte_rate = mp3info.bitrate / 8 * 1000
  fmt.block_align = calculate_mpeg_frame_size(mp3info)
  fmt.sample_bits = 65535
  fmt.extra_size = 22
  fmt.head_layer = ACM_LAYERS[mp3info.layer.to_i-1]
  fmt.head_bit_rate = mp3info.bitrate * 1000
  fmt.head_mode = CHANNEL_MODES[mp3info.channel_mode]
  # fmt.head_mode_ext = (mp3info.channel_mode == "JStereo") ? 2**mp3info.mode_extension : 0
  fmt.head_mode_ext = (mp3info.channel_mode == "JStereo") ? 2**mp3info.header[:mode_extension] : 0
  # fmt.head_emphasis = mp3info.emphasis + 1
  fmt.head_emphasis = mp3info.header[:emphasis] + 1
  fmt.head_flags = calculate_mpeg_head_flags(mp3info)
  fmt.pts_low = 0
  fmt.pts_high = 0
  wave.chunks[:fmt] = fmt
  # NuWav::WaveFile.log "fmt: #{fmt}"
  
  # fact chunk
  fact = FactChunk.new
  fact.samples_number = calculate_mpeg_samples_number(file, mp3info)
  wave.chunks[:fact] = fact
  # NuWav::WaveFile.log "fact: #{fact}"
  
  #mext chunk
  mext = MextChunk.new
  mext.sound_information =  5
  mext.sound_information +=  2 if mp3info.header[:padding]
  mext.frame_size = calculate_mpeg_frame_size(mp3info)
  mext.ancillary_data_length = 0
  mext.ancillary_data_def = 0
  wave.chunks[:mext] = mext
  # NuWav::WaveFile.log "mext: #{mext}"
  
  
  #bext chunk
  bext = BextChunk.new
  bext.time_reference_high = 0
  bext.time_reference_low = 0
  bext.version = 1
  bext.coding_history = "A=MPEG1L#{mp3info.layer},F=#{mp3info.samplerate},B=#{mp3info.bitrate},M=#{CODING_HISTORY_MODE[mp3info.channel_mode]},T=PRX\r\n\0\0"
  wave.chunks[:bext] = bext
  # NuWav::WaveFile.log "bext: #{bext}"
  
  #cart chunk
  cart = CartChunk.new
  now = Time.now
  today = Date.today
  later = today << 12
  cart.version = '0101'
  cart.title = File.basename(file_name) # this is just a default
  cart.start_date = today.strftime("%Y-%m-%d")
  cart.start_time = now.strftime("%H:%M:%S")
  cart.end_date = later.strftime("%Y-%m-%d")
  cart.end_time = now.strftime("%H:%M:%S")
  cart.producer_app_id = 'NuWav'
  cart.producer_app_version = '1.0'
  cart.level_reference = 0
  cart.tag_text = "\r\n"
  wave.chunks[:cart] = cart
  # NuWav::WaveFile.log "cart: #{cart}"
  wave
end

.parse(wave_file) ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 7

def self.parse(wave_file)
  NuWav::WaveFile.new.parse(wave_file)
end

Instance Method Details

#duration ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 79

def duration
  fmt = @chunks[:fmt]
  
  if (PCM_COMPRESSION.include?(fmt.compression_code.to_i))
    data = @chunks[:data]
    data.size / (fmt.sample_rate * fmt.number_of_channels * (fmt.sample_bits / 8))
  elsif (fmt.compression_code.to_i == MPEG_COMPRESSION)
    # <chunk type:fact samples_number:78695424 />
    fact = @chunks[:fact]
    fact.samples_number / fmt.sample_rate
  else
    raise "Duration implemented for PCM and MEPG files only."
  end
end

#is_mpeg? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/nu_wav/wave_file.rb', line 94

def is_mpeg?
  (@chunks[:fmt] && (@chunks[:fmt].compression_code.to_i == MPEG_COMPRESSION))
end

#is_pcm? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/nu_wav/wave_file.rb', line 98

def is_pcm?
  (@chunks[:fmt] && (PCM_COMPRESSION.include?(@chunks[:fmt].compression_code.to_i)))
end

#parse(wave_file) ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 15

def parse(wave_file)
  NuWav::WaveFile.log "Processing wave file #{wave_file.inspect}...."
  wave_file_size = File.size(wave_file)

  File.open(wave_file, File::RDWR) do |f|

    #only for windows, make sure we are operating in binary mode 
    f.binmode
    #start at the very beginning, a very good place to start
    f.seek(0)

    riff, riff_length = read_chunk_header(f)
    NuWav::WaveFile.log "riff: #{riff}"
    NuWav::WaveFile.log "riff_length: #{riff_length}"
    NuWav::WaveFile.log "wave_file_size: #{wave_file_size}"

    raise NotRIFFFormat unless riff == 'RIFF' || riff == 'RF64'
    riff_end = [f.tell + riff_length, wave_file_size].min

    riff_type = f.read(4)
    raise NotWAVEFormat unless riff_type == 'WAVE'

    @header = RiffChunk.new(riff, riff_length, riff_type)

    while (f.tell + 8) <= riff_end
      NuWav::WaveFile.log "while #{f.tell} < #{riff_end}"
      chunk_name, chunk_length = read_chunk_header(f)
      fpos = f.tell

      NuWav::WaveFile.log "found chunk: '#{chunk_name}', size #{chunk_length}"
      
      if chunk_name && chunk_length

        self.chunks[chunk_name.to_sym] = chunk_class(chunk_name).parse(chunk_name, chunk_length, f)
        parsed_chunk_size = self.chunks[chunk_name.to_sym].size

        NuWav::WaveFile.log "about to do a seek..."
        NuWav::WaveFile.log "f.seek #{fpos} + #{parsed_chunk_size}"
        f.seek(fpos + parsed_chunk_size)
        NuWav::WaveFile.log "seek done"

        if parsed_chunk_size.odd?
          NuWav::WaveFile.log("parsed_chunk_size is ODD #{chunk_name}: #{parsed_chunk_size}")
          pad = f.read(1)
          if (pad.nil? || pad.ord != 0)
            NuWav::WaveFile.log("NOT PADDED")
            self.chunks[chunk_name.to_sym].pad_byte = false
            f.seek(fpos + parsed_chunk_size)
          else
            self.chunks[chunk_name.to_sym].pad_byte = true
          end
        end

      else
        NuWav::WaveFile.log "chunk or length was off - remainder of file does not parse properly: #{riff_end} - #{fpos} = #{riff_end - fpos}"
        f.seek(riff_end)
      end
    end
  end
  @chunks.each{|k,v| NuWav::WaveFile.log "#{k}: #{v}\n\n" unless k.to_s == 'data'}
  NuWav::WaveFile.log "parse done"
  self
end

#to_file(file_name, options = {}) ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 110

def to_file(file_name, options={})
  if options[:add_extension] && !(file_name =~ /\.wav/)
    file_name += ".wav"
  end
  NuWav::WaveFile.log "NuWav::WaveFile.to_file: file_name = #{file_name}"
  
  #get all the chunks together to get final length
  chunks_out = [:fmt, :fact, :mext, :bext, :cart, :data].inject([]) do |list, chunk|
    if self.chunks[chunk]
      out = self.chunks[chunk].to_binary(options)
      NuWav::WaveFile.log out.length
      list << out
    end
    list
  end
  
  # TODO: handle other chunks not in the above list, but that might have been in a parsed wav
  
  riff_length = chunks_out.inject(0){|sum, chunk| sum += chunk.size}
  NuWav::WaveFile.log "NuWav::WaveFile.to_file: riff_length = #{riff_length}"
  
  #open file for writing
  open(file_name, "wb") do |o|
    #write the header
    o << "RIFF"
    o << [(riff_length + 4)].pack('V')
    o <<  "WAVE"
    #write the chunks
    chunks_out.each{|c| o << c}
  end      

end

#to_s ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 102

def to_s
  out = "NuWav:#{@header}\n"
  out = [:fmt, :fact, :mext, :bext, :cart, :data ].inject(out) do |s, chunk| 
    s += "#{self.chunks[chunk]}\n" if self.chunks[chunk]
    s
  end
end

#write_data_file(file_name) ⇒ Object 



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# File 'lib/nu_wav/wave_file.rb', line 143

def write_data_file(file_name)
  open(file_name, "wb") do |o|
    o << chunks[:data].data
  end      
end