下面我們來看一篇關於Swift 視頻錄制之調用攝像頭錄像，並保存到系統相冊例子，這個是開發時的入門教程，具體的如下。

1，技術介紹

（1）AVFoundation.framework 框架提供了 AVCaptureSession 類。使用它可以實現視頻捕獲功能。
（2）使用 AVCaptureVideoPreviewLayer 可以將攝像頭拍攝的畫面實時顯示在 ViewController 上。
（3）對於捕獲到的視頻，我們使用 AVCaptureMovieFileOutput 將其輸出到文件中。

2，下面實現一個錄像功能

（1）點擊“開始”按鈕，開始錄制視頻。默認先保存到 Documents 目錄下，命名為 temp.mp4。
（2）點擊“停止”按鈕，停止視頻錄制。將錄制好的錄像再轉存到系統照片庫中。

3，效果圖如下：

4，樣例代碼

import UIKit
import AVFoundation
import Photos
 
class ViewController: UIViewController , AVCaptureFileOutputRecordingDelegate {
    
    //視頻捕獲會話。它是input和output的橋梁。它協調著intput到output的數據傳輸
    let captureSession = AVCaptureSession()
    //視頻輸入設備
    let videoDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
    //音頻輸入設備
    let audioDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeAudio)
    //將捕獲到的視頻輸出到文件
    let fileOutput = AVCaptureMovieFileOutput()
    
    //開始、停止按鈕
    var startButton, stopButton : UIButton!
    //表示當時是否在錄像中
    var isRecording = false
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        //添加視頻、音頻輸入設備
        let videoInput = try! AVCaptureDeviceInput(device: self.videoDevice)
        self.captureSession.addInput(videoInput)
        let audioInput = try! AVCaptureDeviceInput(device: self.audioDevice)
        self.captureSession.addInput(audioInput);
        
        //添加視頻捕獲輸出
        self.captureSession.addOutput(self.fileOutput)
        
        //使用AVCaptureVideoPreviewLayer可以將攝像頭的拍攝的實時畫面顯示在ViewController上
        let videoLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
        videoLayer.frame = self.view.bounds
        videoLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
        self.view.layer.addSublayer(videoLayer)
        
        //創建按鈕
        self.setupButton()
        //啟動session會話
        self.captureSession.startRunning()
    }
    
    //創建按鈕
    func setupButton(){
        //創建開始按鈕
        self.startButton = UIButton(frame: CGRectMake(0,0,120,50))
        self.startButton.backgroundColor = UIColor.redColor();
        self.startButton.layer.masksToBounds = true
        self.startButton.setTitle("開始", forState: .Normal)
        self.startButton.layer.cornerRadius = 20.0
        self.startButton.layer.position = CGPoint(x: self.view.bounds.width/2 - 70,
                                                  y:self.view.bounds.height-50)
        self.startButton.addTarget(self, action: #selector(onClickStartButton(_:)),
                                   forControlEvents: .TouchUpInside)
        
        //創建停止按鈕
        self.stopButton = UIButton(frame: CGRectMake(0,0,120,50))
        self.stopButton.backgroundColor = UIColor.grayColor();
        self.stopButton.layer.masksToBounds = true
        self.stopButton.setTitle("停止", forState: .Normal)
        self.stopButton.layer.cornerRadius = 20.0
        
        self.stopButton.layer.position = CGPoint(x: self.view.bounds.width/2 + 70,
                                                 y:self.view.bounds.height-50)
        self.stopButton.addTarget(self, action: #selector(onClickStopButton(_:)),
                                  forControlEvents: .TouchUpInside)
        
        //添加按鈕到視圖上
        self.view.addSubview(self.startButton);
        self.view.addSubview(self.stopButton);
    }
    
    //開始按鈕點擊，開始錄像
    func onClickStartButton(sender: UIButton){
        if !self.isRecording {
            //設置錄像的保存地址（在Documents目錄下，名為temp.mp4）
            let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,
                                                            .UserDomainMask, true)
            let documentsDirectory = paths[0] as String
            let filePath : String? = "\(documentsDirectory)/temp.mp4"
            let fileURL : NSURL = NSURL(fileURLWithPath: filePath!)
            //啟動視頻編碼輸出
            fileOutput.startRecordingToOutputFileURL(fileURL, recordingDelegate: self)
            
            //記錄狀態：錄像中...
            self.isRecording = true
            //開始、結束按鈕顏色改變
            self.changeButtonColor(self.startButton, color: UIColor.grayColor())
            self.changeButtonColor(self.stopButton, color: UIColor.redColor())
        }
    }
    
    //停止按鈕點擊，停止錄像
    func onClickStopButton(sender: UIButton){
        if self.isRecording {
            //停止視頻編碼輸出
            fileOutput.stopRecording()
            
            //記錄狀態：錄像結束
            self.isRecording = false
            //開始、結束按鈕顏色改變
            self.changeButtonColor(self.startButton, color: UIColor.redColor())
            self.changeButtonColor(self.stopButton, color: UIColor.grayColor())
        }
    }
    
    //修改按鈕的顏色
    func changeButtonColor(target: UIButton, color: UIColor){
        target.backgroundColor = color
    }
    
    //錄像開始的代理方法
    func captureOutput(captureOutput: AVCaptureFileOutput!,
                       didStartRecordingToOutputFileAtURL fileURL: NSURL!,
                       fromConnections connections: [AnyObject]!) {
    }
    
    //錄像結束的代理方法
    func captureOutput(captureOutput: AVCaptureFileOutput!,
                       didFinishRecordingToOutputFileAtURL outputFileURL: NSURL!,
                       fromConnections connections: [AnyObject]!, error: NSError!) {
        var message:String!
        //將錄制好的錄像保存到照片庫中
        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(outputFileURL)
            }, completionHandler: { (isSuccess: Bool, error: NSError?) in
                if isSuccess {
                    message = "保存成功!"
                } else{
                    message = "保存失敗：\(error!.localizedDescription)"
                }
                
                dispatch_async(dispatch_get_main_queue(), {
                    //彈出提示框
                    let alertController = UIAlertController(title: message,
                        message: nil, preferredStyle: .Alert)
                    let cancelAction = UIAlertAction(title: "確定", style: .Cancel, handler: nil)
                    alertController.addAction(cancelAction)
                    self.presentViewController(alertController, animated: true, completion: nil)
                })
        })
    }
}