How to record a video with avfoundation in Swift?

Question

I am trying to figure out how to record a video using AVFoundation in Swift. I have got as far as creating a custom camera but I only figured out how to take still pictures with it and I can't figure out how to record video. From what I understand you have to use AVCaptureVideoDataOutput to get the data from the recording but I can't figure out how to start the recording and implement the delegate methods.

The whole AVFoundation Programing Guide/Still and Video Media Capture is in Objective-C and I can't seem to decipher it out. Here's my attempt to accomplish this task:

First I set up the camera/capture session

override func viewDidLoad() {
    super.viewDidLoad()

    captureSession.sessionPreset = AVCaptureSessionPresetHigh
    let devices = AVCaptureDevice.devices()
    for device in devices {
        if (device.hasMediaType(AVMediaTypeVideo)) {
            if(device.position == AVCaptureDevicePosition.Back) {
                captureDevice = device as? AVCaptureDevice
                if captureDevice != nil {
                    beginSession()
                }
            }
        }
    }

}

Then once beginSession() is called I set up the live feed

func beginSession() {
    var err : NSError? = nil
    captureSession.addInput(AVCaptureDeviceInput(device: captureDevice, error: &err))
    if err != nil {
        println("error: \(err?.localizedDescription)")
    }
    previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    self.cameraView.layer.addSublayer(previewLayer)
    self.cameraView.bringSubviewToFront(takePhotoButton)
    self.cameraView.bringSubviewToFront(self.snappedPicture)
    self.cameraView.bringSubviewToFront(self.backButton)
    previewLayer?.frame = self.cameraView.layer.frame
    captureSession.startRunning()
}

Here's where I get stuck where the user presses record to actually record and capture a video:

@IBAction func takeVideoAction(sender: AnyObject) {

    var recordingDelegate:AVCaptureFileOutputRecordingDelegate? = self

    var videoFileOutput = AVCaptureMovieFileOutput()
    self.captureSession.addOutput(videoFileOutput)

    let filePath = NSURL(fileURLWithPath: "filePath")

    videoFileOutput.startRecordingToOutputFileURL(filePath, recordingDelegate: recordingDelegate)

}

Then I call self.videoFileOutput.stopRecording().

Then lastly the delegate methods

func captureOutput(captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAtURL outputFileURL: NSURL!, fromConnections connections: [AnyObject]!, error: NSError!) {
    return
}

func captureOutput(captureOutput: AVCaptureFileOutput!, didStartRecordingToOutputFileAtURL fileURL: NSURL!, fromConnections connections: [AnyObject]!) {
    return
}

And nothing happens as you can imagine because I can't figure out how to implement it correctly.

Check if the file path is really correct. It must be in an existing directory. — findall, Oct 21 '15 at 06:11
not quite sure maybe just tell the user when the camera is recording and when it is finished recording, however I can't even figure out how to record and so I've never actually have gotten the delegate methods to get called — Garret Kaye, Oct 23 '15 at 04:13

liuyaodong · Accepted Answer · 2015-10-23T04:50:01.500

17

I have tried your code. When set a meaningful filePath, everything goes fine. Change your filePath like this and you will get the delegate methods invoked:

    let documentsURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0]
    let filePath = documentsURL.URLByAppendingPathComponent("temp")

    // Do recording and save the output to the `filePath`
    videoFileOutput.startRecordingToOutputFileURL(filePath, recordingDelegate: recordingDelegate)

edited Oct 23 '15 at 04:50

answered Oct 23 '15 at 04:43

liuyaodong

2,477
13
31

Do you know where I can find the recorded video, I can't locate the directory anywhere on my phone or grab it anywhere using code – Garret Kaye Oct 23 '15 at 15:21
It's under the document directory of your app. You may refer to [this answer](http://stackoverflow.com/a/31977276/2638425) for locating it. – liuyaodong Oct 24 '15 at 03:35
So one more question, I'm having trouble playing back the video because the recordingOutputURL doesn't work when I try to play a video by its URL. Any suggestions? – Garret Kaye Oct 24 '15 at 15:11
can you elaborate it? how do you play it? do you play the video when it has done with recording? – liuyaodong Oct 25 '15 at 06:13
I tried the code above and my app crashes. do you mind share the working code @jimmy – Apr 25 '16 at 16:37
i am trying it, but getting delegate error. Cannot convert value of type 'ViewController' to specified type 'AVCaptureFileOutputRecordingDelegate?' – Akhilesh Sharma Apr 06 '17 at 07:41
@AkhileshSharma you need to make your 'ViewController' inherit from the 'AVCaptureFileOutoutRecordingDelegate' protocol and implement it's delegate methods – Mehrdadmaskull Jul 04 '17 at 04:24

How to record a video with avfoundation in Swift?

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