Module: Ogg::Codecs::VorbisComments

Included in:
Opus, Speex, Vorbis
Defined in:
lib/ogg/codecs/comments.rb

Overview

See http://www.xiph.org/vorbis/doc/v-comment.html Methods to pack/unpack vorbis comment packets intended to be included into Codec classes

Instance Method Summary collapse

Instance Method Details

#binary_size(s) ⇒ Object 



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# File 'lib/ogg/codecs/comments.rb', line 56

def binary_size(s)
  if RUBY_VERSION[0..2] == "1.8"
    s.size
  else
    s.dup.force_encoding("BINARY").size
  end
end

#pack_comments(tag, vendor, preamble = "") ⇒ Object

Pack tag Hash and vendor string into an ogg packet.



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# File 'lib/ogg/codecs/comments.rb', line 35

def pack_comments(tag, vendor, preamble="")
  packet_data = "".force_encoding("binary")
  packet_data << preamble
  
  packet_data << [ vendor.length ].pack("V")
  packet_data << vendor
  
  packet_data << [tag.size].pack("V")
  tag.each do |k,v|
    tag_data = "#{ k }=#{ v }"
    unless RUBY_VERSION[0..2] == "1.8"
      tag_data.force_encoding("binary")
    end
    packet_data << [ binary_size(tag_data) ].pack("V")
    packet_data << tag_data
  end
  
  packet_data << "\001"
  packet_data
end

#unpack_comments(packet, preamble = "") ⇒ Object

unpack a packet, skipping the preamble returns a 2 element array being a Hash of tag/value pairs and the vendor string



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# File 'lib/ogg/codecs/comments.rb', line 10

def unpack_comments(packet, preamble="")
  pio = StringIO.new(packet)
  pio.read(preamble.length)
  
  vendor_length = pio.read(4).unpack("V").first
  vendor = pio.read(vendor_length)
  
  tag = {}
  tag_size = pio.read(4).unpack("V")[0]
  
  tag_size.times do |i|
    size = pio.read(4).unpack("V")[0]
    comment = pio.read(size)
    unless RUBY_VERSION[0..2] == "1.8"
      comment.force_encoding("UTF-8")
    end
    key, val = comment.split(/=/, 2)
    tag[key.downcase] = val
  end
  
  #framing bit = pio.read(1).unpack("C")[0] 
  [ tag, vendor ]
end