screencast.rb

require 'osx/cocoa'
include OSX
require_framework 'QTKit'

class Screen
  def self.capture
    screenshot = OSX::CGWindowListCreateImage(OSX::NSScreen.mainScreen.frame, OSX::KCGWindowListOptionOnScreenOnly, OSX::KCGNullWindowID, OSX::KCGWindowImageDefault)
    screenshot.retain
  end
  
  def self.to_nsimage(cgimage)
    bitmapRep = NSBitmapImageRep.alloc.initWithCGImage(cgimage)
    blob = bitmapRep.representationUsingType_properties(NSJPEGFileType, nil)
    nsimage = NSImage.alloc.initWithData(blob)
    nsimage
  end
end

  error = nil
  mMovie = QTMovie.alloc.initToWritableData_error(NSMutableData.data, error)
  images = []
  
  80.times {
    images << Screen.capture
  }
    
  puts "Now encoding..."
  
  images.each do |img|
    mMovie.objc_send :addImage, Screen.to_nsimage(img),
                 :forDuration, QTMakeTime(1,20),
                 :withAttributes, {:QTAddImageCodecType => "mp4v"}
    img.release
  end
  
  mMovie.objc_send :writeToFile, "screencast.mov",
                  :withAttributes, {:QTMovieFlatten => true}
                  
  puts "Done!!"