Swift - 如何使用 UIImagePickerController 录制 MP4 格式的视频？

Question

我正在创建一个应用程序，我需要在其中录制视频并将其上传到服务器。现在我的项目也有安卓版本了。要支持 android 版本，我必须以 mp4 格式录制视频。我按照this教程将UIImagePicker媒体类型设置为电影格式imagePicker.mediaTypes = [kUTTypeMovie as String]

UIImagePickerController 非常适合我的要求，我唯一需要更改的是其保存格式为 mp4。我在mediaTypes 中尝试了kUTTypeMPEG4，但它在运行时抛出错误，没有错误描述。

这是我的视频捕捉功能

func startCameraFromViewController() {

        if UIImagePickerController.isSourceTypeAvailable(.Camera) == false {
            return
        }
        viewBlack.hidden = false
        presentViewController(cameraController, animated: false, completion: nil)

        cameraController.sourceType = .Camera

        cameraController.mediaTypes = [kUTTypeMovie as String]
        //cameraController.mediaTypes = [kUTTypeMPEG4 as String]
        cameraController.cameraCaptureMode = .Video
        cameraController.videoQuality = .TypeMedium
        if(getPurchaseId() as! Int == 0)
        {
            if(txtBenchMark.text?.isEmpty == false)
            {
                cameraController.videoMaximumDuration = NSTimeInterval(300.0)
            }else{
                cameraController.videoMaximumDuration = NSTimeInterval(60.0)
            }
        }else{
            cameraController.videoMaximumDuration = NSTimeInterval(600.0)
        }
        cameraController.allowsEditing = false
    }

我正在使用带有Use Legacy swift Language version = Yes 的 Swift 2.2 和 Xcode 8

也欢迎任何替代解决方案。提前致谢。

编辑： 我发现没有办法直接快速录制mp4格式的视频。只能从苹果的quicktime mov格式转换成需要的格式。

Answer 1

这里有一些代码可用于将录制的视频转换为 MP4：

func encodeVideo(videoURL: NSURL)  {
let avAsset = AVURLAsset(URL: videoURL, options: nil)

var startDate = NSDate()

//Create Export session
exportSession = AVAssetExportSession(asset: avAsset, presetName: AVAssetExportPresetPassthrough)

// exportSession = AVAssetExportSession(asset: composition, presetName: mp4Quality)
//Creating temp path to save the converted video


let documentsDirectory = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0]
let myDocumentPath = NSURL(fileURLWithPath: documentsDirectory).URLByAppendingPathComponent("temp.mp4").absoluteString
let url = NSURL(fileURLWithPath: myDocumentPath)

let documentsDirectory2 = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0] as NSURL

let filePath = documentsDirectory2.URLByAppendingPathComponent("rendered-Video.mp4")
deleteFile(filePath)

//Check if the file already exists then remove the previous file
if NSFileManager.defaultManager().fileExistsAtPath(myDocumentPath) {
    do {
        try NSFileManager.defaultManager().removeItemAtPath(myDocumentPath)
    }
    catch let error {
        print(error)
    }
}

 url

exportSession!.outputURL = filePath
exportSession!.outputFileType = AVFileTypeMPEG4
exportSession!.shouldOptimizeForNetworkUse = true
var start = CMTimeMakeWithSeconds(0.0, 0)
var range = CMTimeRangeMake(start, avAsset.duration)
exportSession.timeRange = range

exportSession!.exportAsynchronouslyWithCompletionHandler({() -> Void in
    switch self.exportSession!.status {
    case .Failed:
        print("%@",self.exportSession?.error)
    case .Cancelled:
        print("Export canceled")
    case .Completed:
        //Video conversion finished
        var endDate = NSDate()

        var time = endDate.timeIntervalSinceDate(startDate)
        print(time)
        print("Successful!")
        print(self.exportSession.outputURL)

    default:
        break
    }

})


}

func deleteFile(filePath:NSURL) {
guard NSFileManager.defaultManager().fileExistsAtPath(filePath.path!) else {
    return
}

do {
    try NSFileManager.defaultManager().removeItemAtPath(filePath.path!)
}catch{
    fatalError("Unable to delete file: \(error) : \(__FUNCTION__).")
}
}

来源：https://stackoverflow.com/a/39329155/4786204

Answer 2

我对以下 2 个答案进行了一些修改，使其与 Swift 5 兼容：
https://stackoverflow.com/a/40354948/2470084
https://stackoverflow.com/a/39329155/2470084

import AVFoundation

func encodeVideo(videoURL: URL){
    let avAsset = AVURLAsset(url: videoURL)
    let startDate = Date()
    let exportSession = AVAssetExportSession(asset: avAsset, presetName: AVAssetExportPresetPassthrough)
    
    let docDir = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
    let myDocPath = NSURL(fileURLWithPath: docDir).appendingPathComponent("temp.mp4")?.absoluteString
    
    let docDir2 = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0] as NSURL
    
    let filePath = docDir2.appendingPathComponent("rendered-Video.mp4")
    deleteFile(filePath!)
    
    if FileManager.default.fileExists(atPath: myDocPath!){
        do{
            try FileManager.default.removeItem(atPath: myDocPath!)
        }catch let error{
            print(error)
        }
    }
    
    exportSession?.outputURL = filePath
    exportSession?.outputFileType = AVFileType.mp4
    exportSession?.shouldOptimizeForNetworkUse = true
    
    let start = CMTimeMakeWithSeconds(0.0, preferredTimescale: 0)
    let range = CMTimeRange(start: start, duration: avAsset.duration)
    exportSession?.timeRange = range
    
    exportSession!.exportAsynchronously{() -> Void in
        switch exportSession!.status{
        case .failed:
            print("\(exportSession!.error!)")
        case .cancelled:
            print("Export cancelled")
        case .completed:
            let endDate = Date()
            let time = endDate.timeIntervalSince(startDate)
            print(time)
            print("Successful")
            print(exportSession?.outputURL ?? "")
        default:
            break
        }
        
    }
}

func deleteFile(_ filePath:URL) {
    guard FileManager.default.fileExists(atPath: filePath.path) else{
        return
    }
    do {
        try FileManager.default.removeItem(atPath: filePath.path)
    }catch{
        fatalError("Unable to delete file: \(error) : \(#function).")
    }
}

Answer 3

在 iOS11 上运行，我们将始终收到 AVAssetExportSession 的 nil 值。对于这种情况，我们有什么解决方案吗？

if let exportSession = AVAssetExportSession(asset: avAsset, presetName: AVAssetExportPresetPassthrough) {
    //work on iOS 9 and 10
} else {
    //always on iOS 11
}

Answer 4

快速swift 4更新之前的答案：

func encodeVideo(videoUrl: URL, outputUrl: URL? = nil, resultClosure: @escaping (URL?) -> Void ) {

    var finalOutputUrl: URL? = outputUrl

    if finalOutputUrl == nil {
        var url = videoUrl
        url.deletePathExtension()
        url.appendPathExtension(".mp4")
        finalOutputUrl = url
    }

    if FileManager.default.fileExists(atPath: finalOutputUrl!.path) {
        print("Converted file already exists \(finalOutputUrl!.path)")
        resultClosure(finalOutputUrl)
        return
    }

    let asset = AVURLAsset(url: videoUrl)
    if let exportSession = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetPassthrough) {
        exportSession.outputURL = finalOutputUrl!
        exportSession.outputFileType = AVFileType.mp4
        let start = CMTimeMakeWithSeconds(0.0, 0)
        let range = CMTimeRangeMake(start, asset.duration)
        exportSession.timeRange = range
        exportSession.shouldOptimizeForNetworkUse = true
        exportSession.exportAsynchronously() {

            switch exportSession.status {
            case .failed:
                print("Export failed: \(exportSession.error != nil ? exportSession.error!.localizedDescription : "No Error Info")")
            case .cancelled:
                print("Export canceled")
            case .completed:
                resultClosure(finalOutputUrl!)
            default:
                break
            }
        }
    } else {
        resultClosure(nil)
    }
}

Answer 5

对先前示例的小重构：

import AVFoundation

extension AVURLAsset {
    func exportVideo(presetName: String = AVAssetExportPresetHighestQuality,
                     outputFileType: AVFileType = .mp4,
                     fileExtension: String = "mp4",
                     then completion: @escaping (URL?) -> Void)
    {
        let filename = url.deletingPathExtension().appendingPathExtension(fileExtension).lastPathComponent
        let outputURL = FileManager.default.temporaryDirectory.appendingPathComponent(filename)

        if let session = AVAssetExportSession(asset: self, presetName: presetName) {
            session.outputURL = outputURL
            session.outputFileType = outputFileType
            let start = CMTimeMakeWithSeconds(0.0, 0)
            let range = CMTimeRangeMake(start, duration)
            session.timeRange = range
            session.shouldOptimizeForNetworkUse = true
            session.exportAsynchronously {
                switch session.status {
                case .completed:
                    completion(outputURL)
                case .cancelled:
                    debugPrint("Video export cancelled.")
                    completion(nil)
                case .failed:
                    let errorMessage = session.error?.localizedDescription ?? "n/a"
                    debugPrint("Video export failed with error: \(errorMessage)")
                    completion(nil)
                default:
                    break
                }
            }
        } else {
            completion(nil)
        }
    }
}

另外：AVAssetExportPresetHighestQuality 预设在 Android / Chrome 上播放视频时有效。

附：请注意，exportVideo 方法的完成处理程序可能不会在主线程上返回。

Answer 6

Swift 5.2更新解决方案

// Don't forget to import AVKit

func encodeVideo(at videoURL: URL, completionHandler: ((URL?, Error?) -> Void)?)  {
    let avAsset = AVURLAsset(url: videoURL, options: nil)

    let startDate = Date()

    //Create Export session
    guard let exportSession = AVAssetExportSession(asset: avAsset, presetName: AVAssetExportPresetPassthrough) else {
        completionHandler?(nil, nil)
        return
    }

    //Creating temp path to save the converted video
    let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0] as URL
    let filePath = documentsDirectory.appendingPathComponent("rendered-Video.mp4")

    //Check if the file already exists then remove the previous file
    if FileManager.default.fileExists(atPath: filePath.path) {
        do {
            try FileManager.default.removeItem(at: filePath)
        } catch {
            completionHandler?(nil, error)
        }
    }

    exportSession.outputURL = filePath
    exportSession.outputFileType = AVFileType.mp4
    exportSession.shouldOptimizeForNetworkUse = true
      let start = CMTimeMakeWithSeconds(0.0, preferredTimescale: 0)
    let range = CMTimeRangeMake(start: start, duration: avAsset.duration)
    exportSession.timeRange = range

    exportSession.exportAsynchronously(completionHandler: {() -> Void in
        switch exportSession.status {
        case .failed:
            print(exportSession.error ?? "NO ERROR")
            completionHandler?(nil, exportSession.error)
        case .cancelled:
            print("Export canceled")
            completionHandler?(nil, nil)
        case .completed:
            //Video conversion finished
            let endDate = Date()

            let time = endDate.timeIntervalSince(startDate)
            print(time)
            print("Successful!")
            print(exportSession.outputURL ?? "NO OUTPUT URL")
            completionHandler?(exportSession.outputURL, nil)

            default: break
        }

    })
}