hachoir-metadata is tool to extract metadata from multimedia files
(sound, video, archives, etc.)
* Support invalid / truncated files
* Unicode compliant (charset ISO-8859-XX, UTF-8, UTF-16), convert
  string to your terminal charset
* Remove duplicate values (and if a string is a substring of another,
  just keep the longest one)
* Set priority to value, so it's possible to filter metadata (option
  --level)
* Only depends on hachoir-parser (and not on libmatroska, libmpeg2,
  libvorbis, etc.)

WWW: http://bitbucket.org/haypo/hachoir/wiki/hachoir-metadata