viddl-rb:
Created by Marc Seeger (@rb2k)
Repo: http://github.com/rb2k/viddl-rb

Installation:

gem install viddl-rb

Usage:

Download a video:
viddl-rb http://www.youtube.com/watch?v=QH2-TGUlwu4

Download a video and extract the audio:
viddl-rb http://www.youtube.com/watch?v=QH2-TGUlwu4 --extract-audio

In both cases we'll name the output file according to the video title.

Youtube plugin specifics:

Download all videos on a playlist:
viddl-rb http://www.youtube.com/playlist?list=PL7E8DA0A515924126

Download all videos from a user:
viddl-rb http://www.youtube.com/user/tedtalksdirector

Filter videos to download from a user/playlist:
viddl-rb http://www.youtube.com/user/tedtalksdirector --filter=internet/i

The --filter argument accepts a regular expression and will only download videos where the title matches the regex. The /i option does a case-insensitive search.

Library Usage:

require 'viddl-rb'

download_urls = ViddlRb.get_urls("http://www.youtube.com/watch?v=QH2-TGUlwu4")
download_urls.first     # => "http://o-o.preferred.arn06s04.v3.lscac ..."

The ViddlRb module has the following module public methods:

• get_urls_names(url) -- Returns an array of one or more hashes that has the keys :url which points to the download url and :name which points to the name (which is a filename safe version of the video title with a file extension). Returns nil if the url is not recognized by any plugins.

• get_urls_exts(url) -- Same as get_urls_names but with just the file extension (for example ".mp4") instead of the full filename, and the :name key is replaced with :ext. Returns nil if the url is not recognized by any plugins.

• get_urls(url) -- Returns an array of download urls for the specified video url. Returns nil if the url is not recognized by any plugins.

• get_names(url) -- Returns an array of filenames for the specified video url. Returns nil if the url is not recognized by any plugins.

• io=(io_object) -- By default all plugin output to stdout will be suppressed when the library is used. If you are interested in the output of a plugin, you can set an IO object that will receive all plugin output using this method. For example:

require 'viddl-rb'

ViddlRb.io = $stdout     # plugins will now write their output to $stdout

All the get methods in the ViddlRb module will raise either a ViddlRb::PluginError or a ViddlRb::DownloadError if the plugin fails. A ViddlRb::PluginError is raised if the plugin fails in an unexpected way, and a ViddlRb::DownloadError is raised if the video could not be downloaded for some reason. An example of that is if a Youtube video is not embeddable - then it can't be downloaded.

begin
  ViddlRb.get_urls(video_url)
rescue ViddlRb::DownloadError => e
  puts "Could not get download url: #{e.message}"
rescue ViddlRb::PluginError => e
  puts "Plugin blew up! #{e.message}\n" +
       "Backtrace:\n#{e.backtrace.join("\n")}"
end

Requirements:

• curl/wget or the progress bar gem
• Nokogiri
• Mechanize
• ffmpeg if you want to extract audio tracks from the videos

Contributors:

• kl: Windows support (who knew!), bug fixes, veoh plugin, metacafe plugin
• divout aka Ivan K: blip.tv plugin, bugfixes
• Sniper: bugfixes
• Serabe aka Sergio Arbeo: packaging viddl as a binary
• laserlemon: Adding gemnasium images to readme