derobo / mediainfo

Ruby wrapper for the mediainfo CLI. http://mediainfo.sourceforge.net

Mediainfo

Mediainfo is a class wrapping the mediainfo CLI.

Installation

$ gem install mediainfo

Usage

info = Mediainfo.new "/path/to/file"

That will issue the system call to mediainfo and parse the output. You can specify an alternate path if necessary:

Mediainfo.path = "/opt/local/bin/mediainfo"

Once you have an info object, you can start inspecting streams and general metadata.

info.streams.count # 2
info.audio?        # true
info.video?        # true
info.image?        # false

When inspecting specific types of streams, you have a couple general API options. The first approach assumes one stream of a given type, a common scenario in many video files, for example.

info.video.count    # 1
info.audio.count    # 1
info.video.duration # 120 (seconds)

Sometimes you'll have more than one stream of a given type. Quicktime files can often contain artifacts like this from somebody editing a more 'normal' file.

info = Mediainfo.new "funky.mov"

info.video?            # true
info.video.count       # 2
info.video.duration    # raises SingleStreamAPIError !
info.video[0].duration # 120
info.video[1].duration # 10

For some more usage examples, please see the very reasonable test suite accompanying the source code for this library. It contains a bunch of relevant usage examples. More docs in the future.. contributions very welcome!

Moving on, REXML is used as the XML parser by default. If you'd like, you can configure Mediainfo to use Hpricot or Nokogiri instead using one of the following approaches:

• define the MEDIAINFO_XML_PARSER environment variable to be the name of the parser as you'd pass to a :gem or :require call.

  e.g. export MEDIAINFO_XML_PARSER=nokogiri

• assign to Mediainfo.xml_parser after you've loaded the gem, following the same naming conventions mentioned previously.

  e.g. Mediainfo.xml_parser = "hpricot"

Once you've got an instance setup, you can call numerous methods to get a variety of information about a file. Some attributes may be present for some files where others are not, but any supported attribute should at least return nil.

For a list of all possible attributes supported:

Mediainfo.supported_attributes

Requirements

This requires at least the following version of the Mediainfo CLI:

MediaInfo Command line,
MediaInfoLib - v0.7.25

Previous versions of this gem(<= 0.5.1) worked against v0.7.11, which did not generate XML output, and is no longer supported.

Contributors

• Seth Thomas Rasmussen - http://greatseth.com
• Peter Vandenberk - http://github.com/pvdb
• Ned Campion - http://github.com/nedcampion
• Daniel Jagszent - http://github.com/d--j