我无法找到仅使用的方法AVCaptureMovieFileOutput，但是您可以添加额外的照片输出并触发照片，而无需在输出之间切换。
我现在的时间很短，但这应该会让你继续前进，直到我可以编辑更多信息。
（请参阅下面的完整实施编辑，以及有限的力展开）
首先在视图控制器中为照片输出设置一个额外的 var
// declare an additional camera output var
var cameraOutput = AVCapturePhotoOutput()
// do this in your 'setupSession' func where you setup your movie output
cameraOutput.isHighResolutionCaptureEnabled = true
captureSession.addOutput(cameraOutput)
使用 cameraOutput 声明一个函数来捕捉你的照片：
func capturePhoto() {
// create settings for your photo capture
let settings = AVCapturePhotoSettings()
let previewPixelType = settings.availablePreviewPhotoPixelFormatTypes.first!
let previewFormat = [
kCVPixelBufferPixelFormatTypeKey as String: previewPixelType,
kCVPixelBufferWidthKey as String: UIScreen.main.bounds.size.width,
kCVPixelBufferHeightKey as String: UIScreen.main.bounds.size.height
] as [String : Any]
settings.previewPhotoFormat = previewFormat
cameraOutput.capturePhoto(with: settings, delegate: self)
}
并符合AVCapturePhotoCaptureDelegate.
我创建了一个单独的类VideoFeed来管理视频捕获会话，所以这个示例是该类的扩展。稍后我将更新有关此的更多信息。
该loadImage(data: Data)函数使用图像调用委托。如果您将其直接放在视图控制器中，则可以忽略该调用，并保存或对生成的照片执行任何您喜欢的操作：
extension VideoFeed: AVCapturePhotoCaptureDelegate {
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photoSampleBuffer: CMSampleBuffer?, previewPhoto previewPhotoSampleBuffer: CMSampleBuffer?, resolvedSettings: AVCaptureResolvedPhotoSettings, bracketSettings: AVCaptureBracketedStillImageSettings?, error: Error?) {
guard error == nil else {
print("Photo Error: \(String(describing: error))")
return
}
guard let sampleBuffer = photoSampleBuffer,
let previewBuffer = previewPhotoSampleBuffer,
let outputData = AVCapturePhotoOutput
.jpegPhotoDataRepresentation(forJPEGSampleBuffer: sampleBuffer, previewPhotoSampleBuffer: previewBuffer) else {
print("Oops, unable to create jpeg image")
return
}
print("captured photo...")
loadImage(data: outputData)
}
func loadImage(data: Data) {
let dataProvider = CGDataProvider(data: data as CFData)
let cgImageRef: CGImage! = CGImage(jpegDataProviderSource: dataProvider!, decode: nil, shouldInterpolate: true, intent: .defaultIntent)
let image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: UIImageOrientation.right)
// do whatever you like with the generated image here...
delegate?.processVideoSnapshot(image)
}
}
编辑：
这是我在测试项目中使用的完整实现。
首先，我将所有 AVFoundation 特定代码移到它自己的VideoFeed类中，并为视图控制器创建了一些回调。
这将关注点分开并将视图控制器的职责限制为：
- 将预览层添加到视图
- 触发和处理捕获的图像/屏幕截图
- 开始/停止视频文件录制。
这是 ViewController 的实现：
ViewController.swift
import UIKit
import AVFoundation
class ViewController: UIViewController, VideoFeedDelegate {
@IBOutlet var cameraView: UIView!
var videoFeed: VideoFeed?
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
// end session
videoFeed?.stopSession()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
// request camera access
AVCaptureDevice.requestAccess(for: AVMediaType.video) { [weak self] granted in
guard granted != false else {
// TODO: show UI stating camera cannot be used, update in settings app...
print("Camera access denied")
return
}
DispatchQueue.main.async {
if self?.videoFeed == nil {
// video access was enabled so setup video feed
self?.videoFeed = VideoFeed(delegate: self)
} else {
// video feed already available, restart session...
self?.videoFeed?.startSession()
}
}
}
}
// MARK: VideoFeedDelegate
func videoFeedSetup(with layer: AVCaptureVideoPreviewLayer) {
// set the layer size
layer.frame = cameraView.layer.bounds
// add to view
cameraView.layer.addSublayer(layer)
}
func processVideoSnapshot(_ image: UIImage?) {
// validate
guard let image = image else {
return
}
// SAVE IMAGE HERE IF DESIRED
// for now just showing in a lightbox/detail view controller
let storyboard = UIStoryboard(name: "Main", bundle: Bundle(for: AppDelegate.self))
let vc = storyboard.instantiateViewController(withIdentifier: "LightboxViewController") as! LightboxViewController
vc.previewImage = image
navigationController?.pushViewController(vc, animated: true)
}
@IBAction func captureButtonTapped(_ sender: Any){
// trigger photo capture from video feed...
// this will trigger a callback to the function above with the captured image
videoFeed?.capturePhoto()
}
}
VideoFeed这是该类的完整实现。
使用这种方法，您可以更轻松地在其他项目中重用视频功能，而无需将其与视图控制器紧密耦合。
VideoFeed.swift
import UIKit
import AVFoundation
/// Defines callbacks associated with the VideoFeed class. Notifies delegate of significant events.
protocol VideoFeedDelegate: class {
/// Callback triggered when the preview layer for this class has been created and configured. Conforming objects should set and maintain a strong reference to this layer otherwise it will be set to nil when the calling function finishes execution.
///
/// - Parameter layer: The video preview layer associated with the active captureSession in the VideoFeed class.
func videoFeedSetup(with layer: AVCaptureVideoPreviewLayer)
/// Callback triggered when a snapshot of the video feed has been generated.
///
/// - Parameter image: <#image description#>
func processVideoSnapshot(_ image: UIImage?)
}
class VideoFeed: NSObject {
// MARK: Variables
/// The capture session to be used in this class.
var captureSession = AVCaptureSession()
/// The preview layer associated with this session. This class has a
/// weak reference to this layer, the delegate (usually a ViewController
/// instance) should add this layer as a sublayer to its preview UIView.
/// The delegate will have the strong reference to this preview layer.
weak var previewLayer: AVCaptureVideoPreviewLayer?
/// The output that handles saving the video stream to a file.
var fileOutput: AVCaptureMovieFileOutput?
/// A reference to the active video input
var activeInput: AVCaptureDeviceInput?
/// Output for capturing frame grabs of video feed
var cameraOutput = AVCapturePhotoOutput()
/// Delegate to receive callbacks about significant events triggered by this class.
weak var delegate: VideoFeedDelegate?
/// The capture connection associated with the fileOutput.
/// Set when fileOutput is created.
var connection : AVCaptureConnection?
// MARK: Public accessors
/// Public initializer. Accepts a delegate to receive callbacks with the preview layer and any snapshot images.
///
/// - Parameter delegate: A reference to an object conforming to VideoFeedDelegate
/// to receive callbacks for significant events in this class.
init(delegate: VideoFeedDelegate?) {
self.delegate = delegate
super.init()
setupSession()
}
/// Public accessor to begin a capture session.
public func startSession() {
guard captureSession.isRunning == false else {
return
}
captureSession.startRunning()
}
/// Public accessor to end the current capture session.
public func stopSession() {
// validate
guard captureSession.isRunning else {
return
}
// end file recording if the session ends and we're currently recording a video to file
if let isRecording = fileOutput?.isRecording, isRecording {
stopRecording()
}
captureSession.stopRunning()
}
/// Public accessor to begin file recording.
public func startRecording() {
guard fileOutput?.isRecording == false else {
stopRecording()
return
}
configureVideoOrientation()
disableSmoothAutoFocus()
guard let url = tempURL() else {
print("Unable to start file recording, temp url generation failed.")
return
}
fileOutput?.startRecording(to: url, recordingDelegate: self)
}
/// Public accessor to end file recording.
public func stopRecording() {
guard fileOutput?.isRecording == true else {
return
}
fileOutput?.stopRecording()
}
/// Public accessor to trigger snapshot capture of video stream.
public func capturePhoto() {
// create settings object
let settings = AVCapturePhotoSettings()
// verify that we have a pixel format type available
guard let previewPixelType = settings.availablePreviewPhotoPixelFormatTypes.first else {
print("Unable to configure photo capture settings, 'availablePreviewPhotoPixelFormatTypes' has no available options.")
return
}
let screensize = UIScreen.main.bounds.size
// setup format configuration dictionary
let previewFormat: [String : Any] = [
kCVPixelBufferPixelFormatTypeKey as String: previewPixelType,
kCVPixelBufferWidthKey as String: screensize.width,
kCVPixelBufferHeightKey as String: screensize.height
]
settings.previewPhotoFormat = previewFormat
// trigger photo capture
cameraOutput.capturePhoto(with: settings, delegate: self)
}
// MARK: Setup functions
/// Handles configuration and setup of the session, inputs, video preview layer and outputs.
/// If all are setup and configured it starts the session.
internal func setupSession() {
captureSession.sessionPreset = AVCaptureSession.Preset.high
guard setupInputs() else {
return
}
setupOutputs()
setupVideoLayer()
startSession()
}
/// Sets up capture inputs for this session.
///
/// - Returns: Returns true if inputs are successfully setup, else false.
internal func setupInputs() -> Bool {
// only need access to this functionality within this function, so declare as sub-function
func addInput(input: AVCaptureInput) {
guard captureSession.canAddInput(input) else {
return
}
captureSession.addInput(input)
}
do {
if let camera = AVCaptureDevice.default(for: AVMediaType.video) {
let input = try AVCaptureDeviceInput(device: camera)
addInput(input: input)
activeInput = input
}
// Setup Microphone
if let microphone = AVCaptureDevice.default(for: AVMediaType.audio) {
let micInput = try AVCaptureDeviceInput(device: microphone)
addInput(input: micInput)
}
return true
} catch {
print("Error setting device video input: \(error)")
return false
}
}
internal func setupOutputs() {
// only need access to this functionality within this function, so declare as sub-function
func addOutput(output: AVCaptureOutput) {
if captureSession.canAddOutput(output) {
captureSession.addOutput(output)
}
}
// file output
let fileOutput = AVCaptureMovieFileOutput()
captureSession.addOutput(fileOutput)
if let connection = fileOutput.connection(with: .video), connection.isVideoStabilizationSupported {
connection.preferredVideoStabilizationMode = .off
self.connection = connection
}
cameraOutput.isHighResolutionCaptureEnabled = true
captureSession.addOutput(cameraOutput)
}
internal func setupVideoLayer() {
let layer = AVCaptureVideoPreviewLayer(session: captureSession)
layer.videoGravity = AVLayerVideoGravity.resizeAspectFill
delegate?.videoFeedSetup(with: layer)
previewLayer = layer
}
// MARK: Helper functions
/// Creates a url in the temporary directory for file recording.
///
/// - Returns: A file url if successful, else nil.
internal func tempURL() -> URL? {
let directory = NSTemporaryDirectory() as NSString
if directory != "" {
let path = directory.appendingPathComponent(NSUUID().uuidString + ".mp4")
return URL(fileURLWithPath: path)
}
return nil
}
/// Disables smooth autofocus functionality on the active device,
/// if the active device is set and 'isSmoothAutoFocusSupported'
/// is supported for the currently set active device.
internal func disableSmoothAutoFocus() {
guard let device = activeInput?.device, device.isSmoothAutoFocusSupported else {
return
}
do {
try device.lockForConfiguration()
device.isSmoothAutoFocusEnabled = false
device.unlockForConfiguration()
} catch {
print("Error disabling smooth autofocus: \(error)")
}
}
/// Sets the current AVCaptureVideoOrientation on the currently active connection if it's supported.
internal func configureVideoOrientation() {
guard let connection = connection, connection.isVideoOrientationSupported,
let currentOrientation = AVCaptureVideoOrientation(rawValue: UIApplication.shared.statusBarOrientation.rawValue) else {
return
}
connection.videoOrientation = currentOrientation
}
}
// MARK: AVCapturePhotoCaptureDelegate
extension VideoFeed: AVCapturePhotoCaptureDelegate {
// iOS 11+ processing
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
guard error == nil, let outputData = photo.fileDataRepresentation() else {
print("Photo Error: \(String(describing: error))")
return
}
print("captured photo...")
loadImage(data: outputData)
}
// iOS < 11 processing
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photoSampleBuffer: CMSampleBuffer?, previewPhoto previewPhotoSampleBuffer: CMSampleBuffer?, resolvedSettings: AVCaptureResolvedPhotoSettings, bracketSettings: AVCaptureBracketedStillImageSettings?, error: Error?) {
if #available(iOS 11.0, *) {
// use iOS 11-only feature
// nothing to do here as iOS 11 uses the callback above
} else {
guard error == nil else {
print("Photo Error: \(String(describing: error))")
return
}
guard let sampleBuffer = photoSampleBuffer,
let previewBuffer = previewPhotoSampleBuffer,
let outputData = AVCapturePhotoOutput
.jpegPhotoDataRepresentation(forJPEGSampleBuffer: sampleBuffer, previewPhotoSampleBuffer: previewBuffer) else {
print("Image creation from sample buffer/preview buffer failed.")
return
}
print("captured photo...")
loadImage(data: outputData)
}
}
/// Creates a UIImage from Data object received from AVCapturePhotoOutput
/// delegate callback and sends to the VideoFeedDelegate for handling.
///
/// - Parameter data: Image data.
internal func loadImage(data: Data) {
guard let dataProvider = CGDataProvider(data: data as CFData), let cgImageRef: CGImage = CGImage(jpegDataProviderSource: dataProvider, decode: nil, shouldInterpolate: true, intent: .defaultIntent) else {
return
}
let image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: UIImageOrientation.right)
delegate?.processVideoSnapshot(image)
}
}
extension VideoFeed: AVCaptureFileOutputRecordingDelegate {
func fileOutput(_ output: AVCaptureFileOutput, didStartRecordingTo fileURL: URL, from connections: [AVCaptureConnection]) {
print("Video recording started: \(fileURL.absoluteString)")
}
func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?) {
guard error == nil else {
print("Error recording movie: \(String(describing: error))")
return
}
UISaveVideoAtPathToSavedPhotosAlbum(outputFileURL.path, nil, nil, nil)
}
}
对于其他使用此功能的人，不要忘记向您的 info.plist 添加权限，以访问相机、照片库和麦克风。
<key>NSCameraUsageDescription</key>
<string>Let us use your camera</string>
<key>NSPhotoLibraryAddUsageDescription</key>
<string>save to images</string>
<key>NSMicrophoneUsageDescription</key>
<string>for sound in video</string>