Swift 視頻錄製之調用網路攝影機錄影，並儲存到系統相簿例子

1，技術介紹

（1）AVFoundation.framework 架構提供了 AVCaptureSession 類。使用它可以實現視頻捕獲功能。
（2）使用 AVCaptureVideoPreviewLayer 可以將網路攝影機拍攝的畫面即時顯示在 ViewController 上。
（3）對於捕獲到的視頻，我們使用 AVCaptureMovieFileOutput 將其輸出到檔案中。

2，下面實現一個錄影功能

（1）點擊“開始”按鈕，開始錄製視頻。預設先儲存到 Documents 目錄下，命名為 temp.mp4。
（2）點擊“停止”按鈕，停止視頻錄製。將錄製好的錄影再轉存到系統照片庫中。

3，效果圖如下：

4，範例代碼

import UIKit
import AVFoundation
import Photos
 
class ViewController: UIViewController , AVCaptureFileOutputRecordingDelegate {
    
    //視頻捕獲會話。它是input和output的橋樑。它協調著intput到output的資料轉送
    let captureSession = AVCaptureSession()
    //視頻輸入裝置
    let videoDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
    //音訊輸入裝置
    let audioDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeAudio)
    //將捕獲到的視頻輸出到檔案
    let fileOutput = AVCaptureMovieFileOutput()
    
    //開始、停止按鈕
    var startButton, stopButton : UIButton!
    //表示當時是否在錄影中
    var isRecording = false
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        //添加視頻、音訊輸入裝置
        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可以將網路攝影機的拍攝的即時畫面顯示在ViewController上
        let videoLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
        videoLayer.frame = self.view.bounds
        videoLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
        self.view.layer.addSublayer(videoLayer)
        
        //建立按鈕
        self.setupButton()
        //啟動session會話
        self.captureSession.startRunning()
    }
    
    //建立按鈕
    func setupButton(){
        //建立開始按鈕
        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)
        
        //建立停止按鈕
        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，開始錄影
    func onClickStartButton(sender: UIButton){
        if !self.isRecording {
            //設定錄影的儲存地址（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)
            
            //選項組：錄影中...
            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，停止錄影
    func onClickStopButton(sender: UIButton){
        if self.isRecording {
            //停止視頻編碼輸出
            fileOutput.stopRecording()
            
            //選項組：錄影結束
            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
    }
    
    //錄影開始的代理方法
    func captureOutput(captureOutput: AVCaptureFileOutput!,
                       didStartRecordingToOutputFileAtURL fileURL: NSURL!,
                       fromConnections connections: [AnyObject]!) {
    }
    
    //錄影結束的代理方法
    func captureOutput(captureOutput: AVCaptureFileOutput!,
                       didFinishRecordingToOutputFileAtURL outputFileURL: NSURL!,
                       fromConnections connections: [AnyObject]!, error: NSError!) {
        var message:String!
        //將錄製好的錄影儲存到照片庫中
        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(outputFileURL)
            }, completionHandler: { (isSuccess: Bool, error: NSError?) in
                if isSuccess {
                    message = "儲存成功!"
                } else{
                    message = "儲存失敗：\(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)
                })
        })
    }
}