使用AVFoundation捕获视频

Question

我一直在寻找Stack,我发现了类似的问题,但没有一个对我有用.我是Swift 3.0的新手.基本上我要做的是使用AVFoundation录制视频.到目前为止,我已设法捕获静止图像,这是我到目前为止的代码

func beginSession() {
    do {
        let deviceInput = try  AVCaptureDeviceInput(device: captureDevice) as AVCaptureDeviceInput
        if captureSession.inputs.isEmpty {
            self.captureSession.addInput(deviceInput)
        }
        stillImageOutput.outputSettings = [AVVideoCodecKey:AVVideoCodecJPEG]

        if captureSession.canAddOutput(stillImageOutput) {
            captureSession.addOutput(stillImageOutput)
        }

    }
    catch {
        print("error: \(error.localizedDescription)")
    }

    guard let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession) else {
        print("no preview layer")
        return
    }

    self.view.layer.addSublayer(previewLayer)
    previewLayer.frame = self.view.layer.frame
    captureSession.startRunning()

    // Subviews
    self.view.addSubview(imgOverlay)
    self.view.addSubview(blur)
    self.view.addSubview(label)
    self.view.addSubview(Flip)
    self.view.addSubview(btnCapture)
}

和

 // SAVE PHOTO
func saveToCamera() {
    if let videoConnection = stillImageOutput.connection(withMediaType: AVMediaTypeVideo) {
        stillImageOutput.captureStillImageAsynchronously(from: videoConnection, completionHandler: { (CMSampleBuffer, Error) in
            if let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(CMSampleBuffer) {
                if let cameraImage = UIImage(data: imageData) {
                    self.flippedImage = UIImage(cgImage: cameraImage.cgImage!, scale: cameraImage.scale, orientation: UIImageOrientation.rightMirrored)
                    UIImageWriteToSavedPhotosAlbum(self.flippedImage, nil, nil, nil)

                }
            }
        })
    }

}

Answer 1

I am going to make it easy for you by posting the entire code you need to make a video recorder in AVFoundation. This code should work if you simply copy and paste it as is. The only thing you need to remember is that you need to connect the camPreview outlet to a UIView in the ViewController in StoryBoard. This UIView should take up the entire contents of the screen. I will follow up with an explanation of the code so you can do your own investigating and modify the video recorder to fit your app's needs. You will also need to make sure you attach the relevant privacy permissions to info.plist which are Privacy - Microphone Usage Description and Privacy - Camera Usage Description or else you will only see a black screen.

NOTE: Right at the bottom, I've added how to play the recorded video under the title "Playing the Recorded Video".

EDIT - I forgot two things which made it crash during recording but I have added them now.

Swift 4

import UIKit

import AVFoundation

class ViewController: UIViewController, AVCaptureFileOutputRecordingDelegate {

    @IBOutlet weak var camPreview: UIView!

    let cameraButton = UIView()

    let captureSession = AVCaptureSession()

    let movieOutput = AVCaptureMovieFileOutput()

    var previewLayer: AVCaptureVideoPreviewLayer!

    var activeInput: AVCaptureDeviceInput!

    var outputURL: URL!

    override func viewDidLoad() {
        super.viewDidLoad()

        if setupSession() {
            setupPreview()
            startSession()
        }

        cameraButton.isUserInteractionEnabled = true

        let cameraButtonRecognizer = UITapGestureRecognizer(target: self, action: #selector(ViewController.startCapture))

        cameraButton.addGestureRecognizer(cameraButtonRecognizer)

        cameraButton.frame = CGRect(x: 0, y: 0, width: 100, height: 100)

        cameraButton.backgroundColor = UIColor.red

        camPreview.addSubview(cameraButton)

    }

    func setupPreview() {
        // Configure previewLayer
        previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        previewLayer.frame = camPreview.bounds
        previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
        camPreview.layer.addSublayer(previewLayer)
    }

    //MARK:- Setup Camera

    func setupSession() -> Bool {

        captureSession.sessionPreset = AVCaptureSession.Preset.high

        // Setup Camera
        let camera = AVCaptureDevice.default(for: AVMediaType.video)!

        do {

            let input = try AVCaptureDeviceInput(device: camera)

            if captureSession.canAddInput(input) {
                captureSession.addInput(input)
                activeInput = input
            }
        } catch {
            print("Error setting device video input: \(error)")
            return false
        }

        // Setup Microphone
        let microphone = AVCaptureDevice.default(for: AVMediaType.audio)!

        do {
            let micInput = try AVCaptureDeviceInput(device: microphone)
            if captureSession.canAddInput(micInput) {
                captureSession.addInput(micInput)
            }
        } catch {
            print("Error setting device audio input: \(error)")
            return false
        }


        // Movie output
        if captureSession.canAddOutput(movieOutput) {
            captureSession.addOutput(movieOutput)
        }

        return true
    }

    func setupCaptureMode(_ mode: Int) {
        // Video Mode

    }

    //MARK:- Camera Session
    func startSession() {

        if !captureSession.isRunning {
            videoQueue().async {
                self.captureSession.startRunning()
            }
        }
    }

    func stopSession() {
        if captureSession.isRunning {
            videoQueue().async {
                self.captureSession.stopRunning()
            }
        }
    }

    func videoQueue() -> DispatchQueue {
        return DispatchQueue.main
    }

    func currentVideoOrientation() -> AVCaptureVideoOrientation {
        var orientation: AVCaptureVideoOrientation

        switch UIDevice.current.orientation {
            case .portrait:
                orientation = AVCaptureVideoOrientation.portrait
            case .landscapeRight:
                orientation = AVCaptureVideoOrientation.landscapeLeft
            case .portraitUpsideDown:
                orientation = AVCaptureVideoOrientation.portraitUpsideDown
            default:
                 orientation = AVCaptureVideoOrientation.landscapeRight
         }

         return orientation
     }

    @objc func startCapture() {

        startRecording()

    }

    //EDIT 1: I FORGOT THIS AT FIRST

    func tempURL() -> URL? {
        let directory = NSTemporaryDirectory() as NSString

        if directory != "" {
            let path = directory.appendingPathComponent(NSUUID().uuidString + ".mp4")
            return URL(fileURLWithPath: path)
        }

        return nil
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        let vc = segue.destination as! VideoPlaybackViewController

        vc.videoURL = sender as? URL

    }

    func startRecording() {

        if movieOutput.isRecording == false {

            let connection = movieOutput.connection(with: AVMediaType.video)

            if (connection?.isVideoOrientationSupported)! {
                connection?.videoOrientation = currentVideoOrientation()
            }

            if (connection?.isVideoStabilizationSupported)! {
                connection?.preferredVideoStabilizationMode = AVCaptureVideoStabilizationMode.auto
            }

            let device = activeInput.device

            if (device.isSmoothAutoFocusSupported) {

                do {
                    try device.lockForConfiguration()
                    device.isSmoothAutoFocusEnabled = false
                    device.unlockForConfiguration()
                } catch {
                   print("Error setting configuration: \(error)")
                }

            }

            //EDIT2: And I forgot this
            outputURL = tempURL()
            movieOutput.startRecording(to: outputURL, recordingDelegate: self)

            }
            else {
                stopRecording()
            }

       }    

   func stopRecording() {

       if movieOutput.isRecording == true {
           movieOutput.stopRecording()
        }
   }

    func capture(_ captureOutput: AVCaptureFileOutput!, didStartRecordingToOutputFileAt fileURL: URL!, fromConnections connections: [Any]!) {

    }

    func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?) {

        if (error != nil) {

            print("Error recording movie: \(error!.localizedDescription)")

        } else {

            let videoRecorded = outputURL! as URL

            performSegue(withIdentifier: "showVideo", sender: videoRecorded)

        }

    }

}

Swift 3

import UIKit
import AVFoundation

class ViewController: UIViewController, AVCaptureFileOutputRecordingDelegate {

@IBOutlet weak var camPreview: UIView!

let cameraButton = UIView()

let captureSession = AVCaptureSession()

let movieOutput = AVCaptureMovieFileOutput()

var previewLayer: AVCaptureVideoPreviewLayer!

var activeInput: AVCaptureDeviceInput!

var outputURL: URL!

override func viewDidLoad() {
    super.viewDidLoad()

    if setupSession() {
        setupPreview()
        startSession()
    }

    cameraButton.isUserInteractionEnabled = true

    let cameraButtonRecognizer = UITapGestureRecognizer(target: self, action: #selector(ViewController.startCapture))

    cameraButton.addGestureRecognizer(cameraButtonRecognizer)

    cameraButton.frame = CGRect(x: 0, y: 0, width: 100, height: 100)

    cameraButton.backgroundColor = UIColor.red

    camPreview.addSubview(cameraButton)

}

func setupPreview() {
    // Configure previewLayer
    previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    previewLayer.frame = camPreview.bounds
    previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
    camPreview.layer.addSublayer(previewLayer)
}

//MARK:- Setup Camera

func setupSession() -> Bool {

    captureSession.sessionPreset = AVCaptureSessionPresetHigh

    // Setup Camera
    let camera = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)

    do {
        let input = try AVCaptureDeviceInput(device: camera)
        if captureSession.canAddInput(input) {
            captureSession.addInput(input)
            activeInput = input
        }
    } catch {
        print("Error setting device video input: \(error)")
        return false
    }

    // Setup Microphone
    let microphone = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeAudio)

    do {
        let micInput = try AVCaptureDeviceInput(device: microphone)
        if captureSession.canAddInput(micInput) {
            captureSession.addInput(micInput)
        }
    } catch {
        print("Error setting device audio input: \(error)")
        return false
    }


    // Movie output
    if captureSession.canAddOutput(movieOutput) {
        captureSession.addOutput(movieOutput)
    }

    return true
}

func setupCaptureMode(_ mode: Int) {
        // Video Mode

}

//MARK:- Camera Session
func startSession() {


    if !captureSession.isRunning {
        videoQueue().async {
            self.captureSession.startRunning()
        }
    }
}

func stopSession() {
    if captureSession.isRunning {
        videoQueue().async {
            self.captureSession.stopRunning()
        }
    }
}

func videoQueue() -> DispatchQueue {
    return DispatchQueue.main
}



func currentVideoOrientation() -> AVCaptureVideoOrientation {
    var orientation: AVCaptureVideoOrientation

    switch UIDevice.current.orientation {
    case .portrait:
        orientation = AVCaptureVideoOrientation.portrait
    case .landscapeRight:
        orientation = AVCaptureVideoOrientation.landscapeLeft
    case .portraitUpsideDown:
        orientation = AVCaptureVideoOrientation.portraitUpsideDown
    default:
        orientation = AVCaptureVideoOrientation.landscapeRight
    }

    return orientation
}

func startCapture() {

    startRecording()

}

//EDIT 1: I FORGOT THIS AT FIRST

func tempURL() -> URL? {
    let directory = NSTemporaryDirectory() as NSString

    if directory != "" {
        let path = directory.appendingPathComponent(NSUUID().uuidString + ".mp4")
        return URL(fileURLWithPath: path)
    }

    return nil
}


func startRecording() {

    if movieOutput.isRecording == false {

        let connection = movieOutput.connection(withMediaType: AVMediaTypeVideo)
        if (connection?.isVideoOrientationSupported)! {
            connection?.videoOrientation = currentVideoOrientation()
        }

        if (connection?.isVideoStabilizationSupported)! {
            connection?.preferredVideoStabilizationMode = AVCaptureVideoStabilizationMode.auto
        }

        let device = activeInput.device
        if (device?.isSmoothAutoFocusSupported)! {
            do {
                try device?.lockForConfiguration()
                device?.isSmoothAutoFocusEnabled = false
                device?.unlockForConfiguration()
            } catch {
                print("Error setting configuration: \(error)")
            }

        }

        //EDIT2: And I forgot this
        outputURL = tempURL()
        movieOutput.startRecording(toOutputFileURL: outputURL, recordingDelegate: self)

    }
    else {
        stopRecording()
    }

}

func stopRecording() {

    if movieOutput.isRecording == true {
        movieOutput.stopRecording()
    }
}

func capture(_ captureOutput: AVCaptureFileOutput!, didStartRecordingToOutputFileAt fileURL: URL!, fromConnections connections: [Any]!) {

}

func capture(_ captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAt outputFileURL: URL!, fromConnections connections: [Any]!, error: Error!) {
    if (error != nil) {
        print("Error recording movie: \(error!.localizedDescription)")
    } else {

        _ = outputURL as URL

    }
    outputURL = nil
}



}

This is How You Should Have Setup Your View Controller

Permissions for Your Info.plist

Setting Up the Recording Delegates

You need to conform to AVCaptureFileOutputRecordingDelegate. According to Apple docs, it defines an interface for delegates of AVCaptureFileOutput to respond to events that occur in the process of recording a single file. It comes with two methods you need to implement and these are the last two methods at the bottom of the code. The first is,

func capture(_ captureOutput: AVCaptureFileOutput!, didStartRecordingToOutputFileAt fileURL: URL!, fromConnections connections: [Any]!) {
}

You can add any logic to this when the video starts recording. In the code example I have given, the video starts recording when you tap the red square button in the left hand corner. The second is,

func capture(_ captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAt outputFileURL: URL!, fromConnections connections: [Any]!, error: Error!) {
    if (error != nil) {
        print("Error recording movie: \(error!.localizedDescription)")
    } else {

        _ = outputURL as URL

    }
    outputURL = nil
}

This is called when the video has finished recording. In the code example I have given the video stops recording after you tap the red square button a second time. When the video has stopped recording, you get an output file URL. This represents your video. You can use this to perhaps segue to another View Controller to play the video in a AVPlayer. Or you can save it. In this example you will notice I have not done much with the output URL though.

To start recording a video I have used a programmatically created button which appears as a red square in the left hand corner and responds to a UITapGesture. You can make a better button in your app.

设置会话

The video recorder needs a capture session which I have setup in setupSession(). Here you add the AVCapture input devices which include the camera and the microphone. According to Apple, AVCaptureDeviceInput is a concrete sub-class of AVCaptureInput you use to capture data from an AVCaptureDevice object. However, the user needs to grant you access to use these so in you info.plist you should add Privacy - Microphone Usage Description and Privacy - Camera Usage Description and give a reason why you want to use the the video recorder and microphone. If you do not do this, you will only get a black screen. The session preset is a constant value indicating the quality level or bitrate of the output. I have set this to high but there are other options you can explore. The movieOutput is of type AVCaptureMovieFileOutput which according to Apple, is a concrete sub-class of AVCaptureFileOutput you use to capture data to a QuickTime movie. This is what actually allows you to record and save the video.

Setting Up The Preview

This is where you setup the camera preview layer which is done in setupPreview(). You setup the preview layer with the capture session you have created with the following AVCaptureVideoPreviewLayer(session: captureSession).

Starting the Session

The final step is to start the session which is done in startSession(). You check if a session is already running and if it is not then you start one.

if !captureSession.isRunning {
    videoQueue().async {
        self.captureSession.startRunning()
    }
}

Starting the Recording

When you tap the red button, the startRecording() method is called. Here I have added methods to handle video orientation and video stabilization. Finally, we see the movieOutput variable again which we setup earlier with our session. We call it to record our movie to outputURL and tell it our delegate methods to handle the start and end of recording are in the same view controller (those last two methods).

Stop Recording

It just so happens that when you tap the red button again, startRecoding is called again but it will notice that some thing is being recorded and call stopRecording.

Playing the Recorded Video

I'm being generous today so I'll throw this in too.

Create a new view controller and call it VideoPlayback. Connect it with your first ViewController using a segue in Storyboard. Give the segue an identifier of "showVideo". Create a UIView and fills up the VideoPlayback's screen and create an outlet to its view controller called videoView. Add the following code to your new VideoPlayback view controller:

Swift 4

import UIKit
import AVFoundation

class VideoPlayback: UIViewController {

    let avPlayer = AVPlayer()
    var avPlayerLayer: AVPlayerLayer!

    var videoURL: URL!
    //connect this to your uiview in storyboard
    @IBOutlet weak var videoView: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        avPlayerLayer = AVPlayerLayer(player: avPlayer)
        avPlayerLayer.frame = view.bounds
        avPlayerLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
        videoView.layer.insertSublayer(avPlayerLayer, at: 0)

        view.layoutIfNeeded()

        let playerItem = AVPlayerItem(url: videoURL as URL)
        avPlayer.replaceCurrentItem(with: playerItem)

        avPlayer.play()
    }
}

Swift 3

import UIKit
import AVFoundation

class VideoPlayback: UIViewController {

    let avPlayer = AVPlayer()
    var avPlayerLayer: AVPlayerLayer!

    var videoURL: URL!
    //connect this to your uiview in storyboard
    @IBOutlet weak var videoView: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        avPlayerLayer = AVPlayerLayer(player: avPlayer)
        avPlayerLayer.frame = view.bounds
        avPlayerLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
        videoView.layer.insertSublayer(avPlayerLayer, at: 0)

        view.layoutIfNeeded()

        let playerItem = AVPlayerItem(url: videoURL as URL)
        avPlayer.replaceCurrentItem(with: playerItem)

        avPlayer.play()
    }
}

Now go back to your last delegate method and modify it as follows:

func capture(_ captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAt outputFileURL: URL!, fromConnections connections: [Any]!, error: Error!) {

    if (error != nil) {
        print("Error recording movie: \(error!.localizedDescription)")
    } else {

        let videoRecorded = outputURL! as URL

        performSegue(withIdentifier: "showVideo", sender: videoRecorded)
    }
}

Finally, create a prepare for segue method that will initialize the videoURL that will play with the AVPlayer.

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    let vc = segue.destination as! VideoPlayback
    vc.videoURL = sender as! URL
}

现在进行测试,返回并开始录制视频.在红色方块的第二个水龙头上,将执行segue,您将看到录制的视频自动播放.

Answer 2

基于@gwinyai 惊人的答案，我制作了一个类似的相机框架。https://github.com/eonist/HybridCamera这也支持拍照，并且没有@Maksim Kniazev描述的由这条线引起的故障问题：

if (connection?.isVideoStabilizationSupported)! {
    connection?.preferredVideoStabilizationMode = AVCaptureVideoStabilizationMode.auto
}