iOS Swift 2 录制视频 AVCaptureSession

Question

我创建了一个 AVCaptureSession 并将前置摄像头附加到它上面

do {
   try captureSession.addInput(AVCaptureDeviceInput(device: captureDevice))
   }catch{print("err")}

现在我想开始和停止录制触摸事件。我该怎么做？

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        print("touch")
        //Start Recording
    }

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
        print("release");
        //End Recording and Save
    }

Answer 1

您没有提及您是使用AVCaptureMovieFileOutput 还是AVCaptureVideoDataOutput 作为会话的输出。前者非常适合快速录制视频，无需进一步编码，后者通过在录制会话期间获取 CMSampleBuffer 块用于更高级的录制。

对于这个答案的范围，我会选择AVCaptureMovieFileOutput，这里是一些极简的起始代码：

import UIKit
import AVFoundation
import AssetsLibrary

class ViewController: UIViewController, AVCaptureFileOutputRecordingDelegate {

var captureSession = AVCaptureSession()

lazy var frontCameraDevice: AVCaptureDevice? = {
    let devices = AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo) as! [AVCaptureDevice]
    return devices.filter{$0.position == .Front}.first
}()

lazy var micDevice: AVCaptureDevice? = {
    return AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeAudio)
}()

var movieOutput = AVCaptureMovieFileOutput()

private var tempFilePath: NSURL = {
    let tempPath = NSURL(fileURLWithPath: NSTemporaryDirectory()).URLByAppendingPathComponent("tempMovie").URLByAppendingPathExtension("mp4").absoluteString
    if NSFileManager.defaultManager().fileExistsAtPath(tempPath) {
        do {
            try NSFileManager.defaultManager().removeItemAtPath(tempPath)
        } catch { }
    }
    return NSURL(string: tempPath)!
}()

private var library = ALAssetsLibrary()


override func viewDidLoad() {
    super.viewDidLoad()
    //start session configuration
    captureSession.beginConfiguration()
    captureSession.sessionPreset = AVCaptureSessionPresetHigh

    // add device inputs (front camera and mic)
    captureSession.addInput(deviceInputFromDevice(frontCameraDevice))
    captureSession.addInput(deviceInputFromDevice(micDevice))

    // add output movieFileOutput
    movieOutput.movieFragmentInterval = kCMTimeInvalid
    captureSession.addOutput(movieOutput)

    // start session
    captureSession.commitConfiguration()
    captureSession.startRunning()
}

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    print("touch")
    // start capture
    movieOutput.startRecordingToOutputFileURL(tempFilePath, recordingDelegate: self)

}

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
    print("release")
    //stop capture
    movieOutput.stopRecording()
}

private func deviceInputFromDevice(device: AVCaptureDevice?) -> AVCaptureDeviceInput? {
    guard let validDevice = device else { return nil }
    do {
        return try AVCaptureDeviceInput(device: validDevice)
    } catch let outError {
        print("Device setup error occured \(outError)")
        return nil
    }
}

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

func captureOutput(captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAtURL outputFileURL: NSURL!, fromConnections connections: [AnyObject]!, error: NSError!) {
    if (error != nil)
    {
        print("Unable to save video to the iPhone  \(error.localizedDescription)")
    }
    else
    {
        // save video to photo album
        library.writeVideoAtPathToSavedPhotosAlbum(outputFileURL, completionBlock: { (assetURL: NSURL?, error: NSError?) -> Void in
            if (error != nil) {
                print("Unable to save video to the iPhone \(error!.localizedDescription)")
            }
            })

        }
    }
}

有关相机捕捉的更多信息，请参阅WWDC 2014 - Session 508