gistfile1.rb

#!/usr/bin/env macruby

framework 'AppKit'
framework 'QTKit'
framework 'QuartzCore'
framework 'CoreVideo'

class AppDelegate
  def applicationDidFinishLaunching(notification)
    @window = NSWindow.alloc.initWithContentRect([200, 300, 640, 480],
      styleMask:NSTitledWindowMask|NSClosableWindowMask|NSMiniaturizableWindowMask,
      backing:NSBackingStoreBuffered,
      defer:false)
    @window.title      = 'MacRuby: The Definitive Guide'
    @window.level      = 3
    @window.delegate   = self

    @window.display
    @window.orderFrontRegardless
    @window.makeMainWindow
    @window.makeKeyWindow

    @session  =  QTCaptureSession.alloc.init

    device = QTCaptureDevice.defaultInputDeviceWithMediaType QTMediaTypeVideo
    device.open nil
    input = QTCaptureDeviceInput.deviceInputWithDevice device
    @session.addInput input, error:nil

    output = QTCaptureDecompressedVideoOutput.alloc.init
    output.automaticallyDropsLateVideoFrames = true
    output.delegate = self

    key = KCVPixelBufferPixelFormatTypeKey
    value = NSNumber.numberWithUnsignedInt KCVPixelFormatType_32BGRA
    pixelBufferAttributes = NSDictionary.dictionaryWithObject value, forKey:key
    pixelBufferAttributes = {KCVPixelBufferPixelFormatTypeKey:KCVPixelFormatType_32BGRA}
    output.pixelBufferAttributes = pixelBufferAttributes
    @session.addOutput output, error:nil
    
    main = CALayer.layer
    main.frame = @window.contentView.frame
    @window.contentView.layer = main
    @window.contentView.wantsLayer = true

    capture = QTCaptureLayer.alloc.initWithSession @session
    capture.frame = @window.contentView.frame
    mirror = CGAffineTransformMakeScale -1, 1
    capture.affineTransform = mirror
    main.addSublayer capture

    @session.startRunning
  end

  def captureOutput captureOutput,
    didOutputVideoFrame:videoFrame,
    withSampleBuffer:sampleBuffer,
    fromConnection:connection

    p captureOutput, videoFrame, sampleBuffer,connection

    p CVPixelBufferGetWidth videoFrame
  end

end

app = NSApplication.sharedApplication
app.delegate = AppDelegate.new

app.run