Video Recording using Macruby & AVFoundation Framework;

gistfile1.rb

#!/usr/local/bin/macruby
framework 'Cocoa'
framework 'AVFoundation'

# because we love blocks, we make NSTimer blocks :-)
class NSTimer
  def self.scheduledTimerWithTimeInterval interval, repeats: repeat_flag, block: block
     self.scheduledTimerWithTimeInterval interval, 
                                  target: self, 
                                selector: 'executeBlockFromTimer:', 
                                userInfo: block, 
                                 repeats: repeat_flag
  end
  def self.timerWithTimeInterval interval, repeats: repeat_flag, block: block
    self.timerWithTimeInterval interval, 
                        target: self, 
                      selector: 'executeBlockFromTimer:', 
                      userInfo: block, 
                       repeats: repeat_flag
  end
  def self.executeBlockFromTimer aTimer
    blck = aTimer.userInfo
    time = aTimer.timeInterval
    blck[time] if blck
  end
end

class VideoRecordDelegate
  attr_accessor :window
  def initialize
    self.conformsToProtocol(Protocol.protocolWithName('NSApplicationDelegate'))
  end
  def applicationDidFinishLaunching aNotification
    @window.delegate = self
    captureSession = AVCaptureSession.alloc.init
    # looking for Video device, if found add into the session
    videoDevice = AVCaptureDevice.defaultDeviceWithMediaType AVMediaTypeVideo
    if videoDevice 
      NSLog("got videoDevice")
      videoInput = AVCaptureDeviceInput.deviceInputWithDevice videoDevice, error:nil
      captureSession.addInput videoInput if videoInput
    end
    
    # looking for Audio device, if found add into the session
    audioDevice = AVCaptureDevice.defaultDeviceWithMediaType AVMediaTypeAudio
    if audioDevice 
      NSLog("got AudioDevice")
      audioInput = AVCaptureDeviceInput.deviceInputWithDevice audioDevice, error:nil
      captureSession.addInput audioInput if audioInput
    end
    
    
    # set Preview layer
    preview_layer = AVCaptureVideoPreviewLayer.layerWithSession captureSession
    preview_layer.sublayerTransform = CATransform3DMakeScale(-1.0, 1.0, 0.0)
    preview_layer.frame = window.contentView.bounds
    preview_layer.videoGravity = AVLayerVideoGravityResizeAspectFill
    
    
    captureMoviePath = "#{NSHomeDirectory()}/Desktop/macruby.mp4"
    captureMovieURL = NSURL.alloc.initFileURLWithPath captureMoviePath
                
    NSLog("recording to #{captureMovieURL.absoluteString}")
    
    # initiate a capture movie URL 
    captureMovieOutput =  AVCaptureMovieFileOutput.alloc.init
    
    captureSession.addOutput captureMovieOutput
    captureSession.startRunning

    # delete macruby.mp4 if it exists
    if NSFileManager.defaultManager.fileExistsAtPath captureMoviePath
      NSFileManager.defaultManager.removeItemAtPath captureMoviePath, error:nil
    end
    # note: must have a delegate
    captureMovieOutput.startRecordingToOutputFileURL captureMovieURL, recordingDelegate:self
    
    
    window.contentView.setWantsLayer true
    window.contentView.layer.addSublayer preview_layer
    
    window.center
    
    captureSession.startRunning 
    
    
    # we want to stop after 20 seconds
    stop_recording_timer = NSTimer.timerWithTimeInterval 20.0, repeats: false, block: -> time do
       # we stop recording
       captureMovieOutput.stopRecording
       # stop the capture Session screen get off
       captureSession.stopRunning
    end
    NSRunLoop.currentRunLoop.addTimer stop_recording_timer, forMode:NSDefaultRunLoopMode #NSEventTrackingRunLoopMode          
  end
  
  # capture Delegates
  def captureOutput captureOutput, didStartRecordingToOutputFileAtURL:fileURL, fromConnections:connections
    NSLog("Started recording to #{fileURL.absoluteString}")
  end
  
  def captureOutput captureOutput, didFinishRecordingToOutputFileAtURL:outputFileURL, fromConnections:connections, error:error
    if error
      NSLog("Failed to record: #{error.localizedDescription}")
    else
      NSLog("Finished recording to #{outputFileURL.absoluteString}")
    end
  end
  
  def windowWillClose(sender); exit(1); end

end

# Create the Application
application = NSApplication.sharedApplication
application.delegate = VideoRecordDelegate.new

# create the Application Window
frame = [0.0, 0.0, 500, 300]
window = NSWindow.alloc.initWithContentRect frame, 
                                  styleMask: NSTitledWindowMask | NSClosableWindowMask,
                                    backing: NSBackingStoreBuffered,
                                      defer: false

window.display
window.makeKeyAndOrderFront(nil)

application.delegate.window = window
application.run