-search | RubyGems.org | your community gem host
--https://rubygems.org/search?utf8=%E2%9C%93&query=ffmpeg
-streamio/streamio-ffmpeg
--https://github.com/streamio/streamio-ffmpeg
-hackerdude/ffmpeg-ruby
--https://github.com/hackerdude/ffmpeg-ruby
-gwik/ffmpeg-ruby
--https://github.com/gwik/ffmpeg-ruby
-ffmpegで動画の各種情報を確認する - Qiita
--http://qiita.com/ymotongpoo/items/eb9754b75606be117b70