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FlacInfo

FlacInfo is a pure Ruby library for reading/writing low level information from Flac (Free Lossless Audio Codec) files.

flacinfo can extract the following information:

• Contents of the STREAMINFO block (bitrate, number of samples, md5 signature etc)
• Contents of the VORBIS_COMMENT block, ie: the tags...
• Contents of the SEEKTABLE block
• Size of PADDING block if present
• Size of CUESHEET block if present. The cuesheet itself is not parsed yet.
• Contents of the APPLICATION block if present.
• Contents of the PICTURE block if present, and write it to an external file (version 0.2).

flacinfo can write the following information back to the file:

• The Vorbis comments (version 0.3).

As an added bonus, if there is data present in a FlacFile APPLICATION block it can parse it, and dump the raw data to the console or a file.

FlacInfo has been tested on Linux and OS X. It should work on any Unix with Ruby, and on Windows as well. If you try the library on another OS/System please do let me know how it works for you. Please report all bugs and issues using FlacInfo's Rubyforge bug tracker.

documentation

Here is FlacInfo's Rdoc documentation.

Here is a brief example irb session:

$ irb --simple-prompt
>> require 'flacinfo'
=> true
>> s = FlacInfo.new("Nightmares On Wax - Smokers Delight - 12 - Mission Venice.flac")
=> #<FlacInfo:0x-4884f05c (STREAMINFO size=34 offset=8) (SEEKTABLE size=324 offset=46) 
(VORBIS_COMMENT size=257 offset=374) (PICTURE size=26748 offset=635) (PADDING size=8104 
offset=27387)>
>> s.comment
=> ["TITLE=Mission Venice", "ARTIST=Nightmares On Wax", "ALBUM=Smokers Delight", 
"DATE=1995", "TRACKNUMBER=12", "TRACKTOTAL=16", "GENRE=Downtempo", 
"DESCRIPTION=Ripped on January 8, 2008", "COMMENT=Ripped on January 8, 2008"]
>> s.comment_del("DESCRIPTION")
=> true
>> s.comment_add("HOW_MUCH_COFFEE_IVE_HAD=Too much")
=> true
>> s.comment
=> ["TITLE=Mission Venice", "ARTIST=Nightmares On Wax", "ALBUM=Smokers Delight", 
"DATE=1995", "TRACKNUMBER=12", "TRACKTOTAL=16", "GENRE=Downtempo", 
"COMMENT=Ripped on January 8, 2008", "HOW_MUCH_COFFEE_IVE_HAD=Too much"]
>> s.meta_flac
METADATA block #0
  type: 0 (STREAMINFO)
  is last: false
  length: 34
  minumum blocksize: 4096 samples
  maximum blocksize: 4096 samples
  minimum framesize: 232 bytes
  maximum framesize: 12897 bytes
  sample rate: 44100 Hz
  channels: 2
  bits-per-sample: 16
  total samples: 7504056
  MD5 signature: 524546dcd49d11b1fa5732be3678cc3e
METADATA block #1
  type: 3 (SEEKTABLE)
  is last: false
  length: 324
  seek points: 18
    point 0: sample number: 0, stream offset: 0, frame samples: 4096
    point 1: sample number: 438272, stream offset: 1027419, frame samples: 4096
    point 2: sample number: 880640, stream offset: 2079152, frame samples: 4096
    point 3: sample number: 1318912, stream offset: 3158943, frame samples: 4096
    point 4: sample number: 1761280, stream offset: 4260790, frame samples: 4096
    point 5: sample number: 2203648, stream offset: 5359532, frame samples: 4096
    point 6: sample number: 2641920, stream offset: 6442430, frame samples: 4096
    point 7: sample number: 3084288, stream offset: 7532631, frame samples: 4096
    point 8: sample number: 3526656, stream offset: 8502857, frame samples: 4096
    point 9: sample number: 3964928, stream offset: 9397068, frame samples: 4096
    point 10: sample number: 4407296, stream offset: 10321587, frame samples: 4096
    point 11: sample number: 4849664, stream offset: 11274462, frame samples: 4096
    point 12: sample number: 5287936, stream offset: 12177399, frame samples: 4096
    point 13: sample number: 5730304, stream offset: 13221471, frame samples: 4096
    point 14: sample number: 6172672, stream offset: 14317190, frame samples: 4096
    point 15: sample number: 6610944, stream offset: 15399346, frame samples: 4096
    point 16: sample number: 7053312, stream offset: 16475547, frame samples: 4096
    point 17: sample number: 7495680, stream offset: 17332415, frame samples: 4096
METADATA block #2
  type: 4 (VORBIS_COMMENT)
  is last: false
  length: 257
  vendor string: reference libFLAC 1.2.1 20070917
  comments: 9
    comment[0]: TITLE=Mission Venice
    comment[1]: ARTIST=Nightmares On Wax
    comment[2]: ALBUM=Smokers Delight
    comment[3]: DATE=1995
    comment[4]: TRACKNUMBER=12
    comment[5]: TRACKTOTAL=16
    comment[6]: GENRE=Downtempo
    comment[7]: COMMENT=Ripped on January 8, 2008
    comment[8]: HOW_MUCH_COFFEE_IVE_HAD=Too much
METADATA block #3
  type: 6 (PICTURE)
  is last: false
  length: 26748
  type: 3 => Cover (front)
  mimetype: image/jpeg
  description: Front cover
  image width: 240
  image height: 240
  colour depth: 24
  number of colours: 0
  image size: 26695 bytes
METADATA block #4
  type: 1 (PADDING)
  is last: true
  length: 8104
=> nil
>> s.padding_resize!(1024)
=> true
>> s.padding
=> {"offset"=>27387, "block_size"=>1024}
>> s.write_picture()
=> nil
>> `ls *jpeg`
=> "Smokers Delight.jpeg\n"
>> quit
$

download

flacinfo-rb Ruby library

Download the Ruby library from the flacinfo-rb rubyforge project page.
You can also install via remote gems:

# gem install -r flacinfo-rb

Or you can use this ebuild if you use Gentoo:

• flacinfo-rb-0.4.ebuild

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