Class: CafInfo

Inherits:
Object
  • Object
show all
Defined in:
lib/cafinfo.rb,
lib/caf/extension_modules.rb

Overview

ruby -d to display debugging infos

Defined Under Namespace

Modules: CafFileMethods, HashKeys

Constant Summary collapse

VERSION = 
"0.2.1"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(filename) ⇒ CafInfo

Instantiate CafInfo object with name filename.



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# File 'lib/cafinfo.rb', line 55

def initialize(filename)
  warn("#{self.class}::new() does not take block; use #{self.class}::open() instead") if block_given?
  @filename = filename
  @header = {}
  reload
end

Instance Attribute Details

#bits_per_channel ⇒ Object (readonly)

the number of bits of sample data for each channel in a frame of data. 0 if the data format does not contain separate samples for each channel (for instance any compressed format)



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# File 'lib/cafinfo.rb', line 46

def bits_per_channel
  @bits_per_channel
end

#bytes_per_packet ⇒ Object (readonly)

the number of bytes in a packet of data.



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# File 'lib/cafinfo.rb', line 36

def bytes_per_packet
  @bytes_per_packet
end

#channels_per_frame ⇒ Object (readonly)

the number of channels in each frame of data



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# File 'lib/cafinfo.rb', line 42

def channels_per_frame
  @channels_per_frame
end

#filename ⇒ Object (readonly)

the original filename



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# File 'lib/cafinfo.rb', line 21

def filename
  @filename
end

#format ⇒ Object (readonly)

a four-character code indicating the general kind of data in the stream



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# File 'lib/cafinfo.rb', line 30

def format
  @format
end

#format_flags ⇒ Object (readonly)

flags specific to each format



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# File 'lib/cafinfo.rb', line 33

def format_flags
  @format_flags
end

#frames_per_packet ⇒ Object (readonly)

the number of sample frames in each packet of data



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# File 'lib/cafinfo.rb', line 39

def frames_per_packet
  @frames_per_packet
end

#length ⇒ Object (readonly)

duration in seconds of audio



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# File 'lib/cafinfo.rb', line 24

def length
  @length
end

#samplerate ⇒ Object (readonly)

the number of sample frames per second of the data



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# File 'lib/cafinfo.rb', line 27

def samplerate
  @samplerate
end

#vbr ⇒ Object (readonly)

variable bitrate => true or false



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# File 'lib/cafinfo.rb', line 49

def vbr
  @vbr
end

#vfr ⇒ Object (readonly)

variable frame rate => true or false



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# File 'lib/cafinfo.rb', line 52

def vfr
  @vfr
end

Class Method Details

.open(*params) ⇒ Object

“block version” of CafInfo::new()



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# File 'lib/cafinfo.rb', line 93

def self.open(*params)
  m = self.new(*params)
  ret = nil
  if block_given?
    begin
      ret = yield(m)
    ensure
      m.close
    end
  else
    ret = m
  end
  ret
end

Instance Method Details

#audio_content ⇒ Object

this method returns the “audio-only” data boundaries of the file, i.e. data chunk content. Returned value is an array

position_in_the_file, length_of_the_data 


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# File 'lib/cafinfo.rb', line 116

def audio_content
  [@chunks[:data].position, @chunks[:data].size]
end

#close ⇒ Object

Flush pending modifications and close the file



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# File 'lib/cafinfo.rb', line 121

def close
  puts "close" if $DEBUG
end

#flush ⇒ Object

close and reopen the file, i.e. commit changes to disk and reload it



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# File 'lib/cafinfo.rb', line 127

def flush
  close
  reload
end

#reload ⇒ Object

reload (or load for the first time) the file from disk

Raises:



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

def reload
  raise(Caf::Error, "empty file") unless File.size?(@filename)

  @file = File.new(filename, "rb")
  @file.extend(CafFileMethods)

  @chunks = {}

  begin
    @header = read_file_header
    chunk = read_audio_description_chunk
    @chunks[chunk.chunk_type.to_sym] = chunk
    puts "Found chunk: #{@chunks[chunk.chunk_type.to_sym]}" if $DEBUG

    until @file.eof? do
      chunk = read_chunk_header
      chunk.read_data(@file)
      @chunks[chunk.chunk_type.to_sym] = chunk

      puts "Found chunk: #{chunk}" if $DEBUG
    end
  ensure
    @file.close
  end

  raise(Caf::Error, "data chunk not found") if @chunks[:data].nil?
  @length = (@frames_per_packet * @chunks[:data].size) / (@samplerate * @bytes_per_packet)
end

#rename(new_filename) ⇒ Object

write to another filename at close()



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# File 'lib/cafinfo.rb', line 109

def rename(new_filename)
  @filename = new_filename
end

#to_s ⇒ Object

inspect inside CafInfo



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# File 'lib/cafinfo.rb', line 133

def to_s
  s = "CAF (version #{@header[:file_version]}) #{@format} #{"VFR " if @vfr}#{@vbr ? "VBR" : "CBR"} #{@samplerate} Hz length #{@length} sec."
  s << ""
  s
end