Почему GStreamer не работает в Windows?

require 'gtk2'
require 'gst'

def os_family
  case RUBY_PLATFORM
    when /ix/i, /ux/i, /gnu/i, /sysv/i, /solaris/i, /sunos/i, /bsd/i
      'unix'
    when /win/i, /ming/i
      'windows'
    else
      'other'
  end
end

Gst.init

pipeline = Gst::Pipeline.new('pipeline1')
videosrc = Gst::ElementFactory.make('videotestsrc', 'videosrc1')
videoconvert = Gst::ElementFactory.make('autovideoconvert', 'videoconvert1')
videosink = Gst::ElementFactory.make('autovideosink', 'videosink1');

pipeline.add(videosrc, videoconvert, videosink)
videosrc >> videoconvert >> videosink

window = Gtk::Window.new('Video test')
window.signal_connect("destroy") { pipeline.stop; Gtk.main_quit }
window.set_default_size(320, 240)
window.show_all

pipeline.bus.add_watch do |bus, message|
  if (message and message.structure and message.structure.name \
  and (message.structure.name == 'prepare-xwindow-id'))
    Gdk::Threads.synchronize do
      Gdk::Display.default.sync
      if not window.destroyed? and window.window
        win_id = nil
        if os_family=='windows'
          win_id = window.window.handle
        else
          win_id = window.window.xid
        end
        imagesink = message.src
        imagesink.set_property("force-aspect-ratio", true)
        imagesink.set_xwindow_id(win_id)
      end
    end
  end
  true
end

pipeline.play
Gtk.main