如何同时录制视频和播放音频（swift教程）

Question

所以您想录制视频并播放用户库中的音乐同时?别再看了。下面是答案。

Answer 1

对于音频播放，您将使用 AVAudioPlayer。您所要做的就是将 AVAudioPlayer 声明为 全局变量 （我将其命名为 audioPlayer）并执行下面的代码。

在用户选择歌曲 he/she想要播放后使用：

func mediaPicker(mediaPicker: MPMediaPickerController, didPickMediaItems mediaItemCollection: MPMediaItemCollection) {
    let pickerItem: MPMediaItem = mediaItemCollection.items[0]
    let songURL = pickerItem.valueForProperty(MPMediaItemPropertyAssetURL)
    if let sURL = songURL as? NSURL
    {
        songTitle = pickerItem.title!
        do
        {
            audioPlayer = try AVAudioPlayer(contentsOfURL: sURL)
        }
        catch
        {
            print("Can't Create Audio Player: \(error)")
        }
    }
    dismissViewControllerAnimated(true, completion: { () -> Void in
        audioPlayer.play()
    })
}

您还需要设置音频会话（在viewDidLoad中）。如果您想在录制时播放音频，这一点至关重要：

 // Audio Session Setup
    do
    {
        try audioSession.setCategory(AVAudioSessionCategoryPlayAndRecord)
    }
    catch
    {
        print("Can't Set Audio Session Category: \(error)")
    }
    AVAudioSessionCategoryOptions.MixWithOthers
    do
    {
        try audioSession.setMode(AVAudioSessionModeVideoRecording)
    }
    catch
    {
        print("Can't Set Audio Session Mode: \(error)")
    }
    // Start Session
    do
    {
        try audioSession.setActive(true)
    }
    catch
    {
        print("Can't Start Audio Session: \(error)")
    }

现在开始视频录制。您将使用 AVCaptureSession。将以下声明为全局变量：

let captureSession = AVCaptureSession()
var currentDevice: AVCaptureDevice?
var videoFileOutput: AVCaptureMovieFileOutput?
var cameraPreviewLayer: AVCaptureVideoPreviewLayer?

然后在viewDidLoad中配置会话。注意：视频预览在容器中，整个视频相关代码在不同的视图控制器中，但仅使用视图而不是容器应该也能正常工作：

// Preset For 720p
captureSession.sessionPreset = AVCaptureSessionPreset1280x720

// Get Available Devices Capable Of Recording Video
let devices = AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo) as! [AVCaptureDevice]

// Get Back Camera
for device in devices
{
    if device.position == AVCaptureDevicePosition.Back
    {
        currentDevice = device
    }
}
let camera = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)

// Audio Input
let audioInputDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeAudio)

do
{
    let audioInput = try AVCaptureDeviceInput(device: audioInputDevice)

    // Add Audio Input
    if captureSession.canAddInput(audioInput)
    {
        captureSession.addInput(audioInput)
    }
    else
    {
        NSLog("Can't Add Audio Input")
    }
}
catch let error
{
    NSLog("Error Getting Input Device: \(error)")
}

// Video Input
let videoInput: AVCaptureDeviceInput
do
{
    videoInput = try AVCaptureDeviceInput(device: camera)

    // Add Video Input
    if captureSession.canAddInput(videoInput)
    {
        captureSession.addInput(videoInput)
    }
    else
    {
        NSLog("ERROR: Can't add video input")
    }
}
catch let error
{
    NSLog("ERROR: Getting input device: \(error)")
}

// Video Output
videoFileOutput = AVCaptureMovieFileOutput()
captureSession.addOutput(videoFileOutput)

// Show Camera Preview
cameraPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
view.layer.addSublayer(cameraPreviewLayer!)
cameraPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
let width = view.bounds.width
cameraPreviewLayer?.frame = CGRectMake(0, 0, width, width)

// Bring Record Button To Front & Start Session
view.bringSubviewToFront(recordButton)
captureSession.startRunning()
print(captureSession.inputs)

然后创建一个 @IBAction 用于处理用户按下录制按钮时的情况（我只是使用了一个简单的按钮，我将其制作成红色和圆形）：

@IBAction func capture(sender: AnyObject) {
    do
    {
        initialOutputURL = try NSFileManager.defaultManager().URLForDirectory(.DocumentDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: true).URLByAppendingPathComponent("output").URLByAppendingPathExtension("mov")
    }
    catch
    {
        print(error)
    }
    if !isRecording
    {
        isRecording = true

        UIView.animateWithDuration(0.5, delay: 0.0, options: [.Repeat, .Autoreverse, .AllowUserInteraction], animations: { () -> Void in
            self.recordButton.transform = CGAffineTransformMakeScale(0.75, 0.75)
            }, completion: nil)

        videoFileOutput?.startRecordingToOutputFileURL(initialOutputURL, recordingDelegate: self)
    }
    else
    {
        isRecording = false

        UIView.animateWithDuration(0.5, delay: 0, options: [], animations: { () -> Void in
            self.recordButton.transform = CGAffineTransformMakeScale(1.0, 1.0)
            }, completion: nil)
        recordButton.layer.removeAllAnimations()
        videoFileOutput?.stopRecording()
    }
}

然后剩下要做的就是将视频保存到（大概）相机胶卷。但我不会包括那个。你必须自己付出一些努力。（提示：UISaveVideoAtPathToSavedPhotosAlbum）

伙计们，就是这样。这就是您如何使用 AVFoundation 录制视频并同时播放音乐库中的音乐。

Answer 2

像下面这样设置 AVAudioSession 后，它会很好地工作。

try? AVAudioSession.sharedInstance().setCategory(AVAudioSession.Category.playAndRecord, mode: AVAudioSession.Mode.videoRecording, options: AVAudioSession.CategoryOptions.mixWithOthers)

如何同时录制视频和播放音频（swift教程）

How to record video and play audio at the same time (swift tutorial)

avfoundation

avaudioplayer

mpmusicplayercontroller

ios

swift