0超越界限空NSArray

Question

我试图合并一个音频和一个视频，这将来自NSFileManager。当我尝试时，我得到了一个错误。然后我创建了另一个项目，它完全没问题。但是，当我尝试在我的主项目中执行此操作时，出现错误。

终止应用程序由于未捕获的异常 'NSRangeException'，原因： '*** - [__ NSArray0 objectAtIndex：]：索引0超越边界空的NSArray'

以下是我尝试合并：

要从Document目录中获取数据，我写了一个名为getData的函数。

func getData(){ 
    let documentsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first! 

    do { 
     // Get the directory contents urls (including subfolders urls) 
     let directoryContents = try FileManager.default.contentsOfDirectory(at: documentsUrl, includingPropertiesForKeys: nil, options: []) 
     print(directoryContents) 

     // if you want to filter the directory contents you can do like this: 
     videoUrlforMarge = directoryContents.filter{ $0.pathExtension == "mov" } as [AnyObject] 
     //videoUrlforMarge.append(directoryContents[1] as AnyObject) 
     print("this video \(videoUrlforMarge[0])") 

     audioUrl = directoryContents.filter{ $0.pathExtension == "caf" } as [AnyObject] 
    } catch let error as NSError { 
     print(error.localizedDescription) 
    } 
} 

这里是我的合并功能：

func mergeFilesWithUrl(videoUrl:NSURL, audioUrl:NSURL) 
{ 
    let mixComposition : AVMutableComposition = AVMutableComposition() 
    var mutableCompositionVideoTrack : [AVMutableCompositionTrack] = [] 
    var mutableCompositionAudioTrack : [AVMutableCompositionTrack] = [] 
    let totalVideoCompositionInstruction : AVMutableVideoCompositionInstruction = AVMutableVideoCompositionInstruction() 

    //start merge 
    let aVideoAsset : AVAsset = AVAsset(url: videoUrl as URL) 
    let aAudioAsset : AVAsset = AVAsset(url: audioUrl as URL) 

    mutableCompositionVideoTrack.append(mixComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid)) 
    mutableCompositionAudioTrack.append(mixComposition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: kCMPersistentTrackID_Invalid)) 

    let aVideoAssetTrack : AVAssetTrack = aVideoAsset.tracks(withMediaType: AVMediaTypeVideo)[0] 
    let aAudioAssetTrack : AVAssetTrack = aAudioAsset.tracks(withMediaType: AVMediaTypeAudio)[0] 

    do{ 
     try mutableCompositionVideoTrack[0].insertTimeRange(CMTimeRangeMake(kCMTimeZero, aVideoAssetTrack.timeRange.duration), of: aVideoAssetTrack, at: kCMTimeZero) 

     try mutableCompositionAudioTrack[0].insertTimeRange(CMTimeRangeMake(kCMTimeZero, aVideoAssetTrack.timeRange.duration), of: aAudioAssetTrack, at: kCMTimeZero) 
    }catch{ 
    } 

    totalVideoCompositionInstruction.timeRange = CMTimeRangeMake(kCMTimeZero,aVideoAssetTrack.timeRange.duration) 

    let mutableVideoComposition : AVMutableVideoComposition = AVMutableVideoComposition() 
    mutableVideoComposition.frameDuration = CMTimeMake(1, 30) 

    mutableVideoComposition.renderSize = CGSize(width: 1280, height: 720) 

    //  playerItem = AVPlayerItem(asset: mixComposition) 
    //  player = AVPlayer(playerItem: playerItem!) 
    // 
    // 
    //  AVPlayerVC.player = player 

    //  let fm = FileManager.default 
    //  let docsurl = try! fm.url(for:.documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false) 
    //  let savePathUrl = docsurl.appendingPathComponent("temp.mp4") 

    //find your video on this URl 
    //let savePathUrl : NSURL = NSURL(fileURLWithPath: NSHomeDirectory() + "/Documents/newVideo.mp4") 
    let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0] 
    let savePathUrl = NSURL(string: ("\(documentsURL.appendingPathComponent("temp"))" + ".mp4")) 

    let VideoFilePath = NSURL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("mergeVideo\(arc4random()%1000)d")!.appendingPathExtension("mp4").absoluteString 

    if FileManager.default.fileExists(atPath: VideoFilePath) 
    { 
     do 
     { 
      try FileManager.default.removeItem(atPath: VideoFilePath) 
     } 
     catch { } 
    } 

    let assetExport: AVAssetExportSession = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)! 
    assetExport.outputFileType = AVFileTypeMPEG4 
    assetExport.outputURL = NSURL(fileURLWithPath: VideoFilePath) as URL 
    assetExport.shouldOptimizeForNetworkUse = true 

    assetExport.exportAsynchronously {() -> Void in 
     switch assetExport.status { 

     case AVAssetExportSessionStatus.completed: 
      //Uncomment this if u want to store your video in asset 

      let assetsLib = ALAssetsLibrary() 
      assetsLib.writeVideoAtPath(toSavedPhotosAlbum: savePathUrl! as URL, completionBlock: nil) 

      print("success") 
     case AVAssetExportSessionStatus.failed: 
      print("failed \(String(describing: assetExport.error))") 
     case AVAssetExportSessionStatus.cancelled: 
      print("cancelled \(String(describing: assetExport.error))") 
     default: 
      print("complete") 
     } 
    } 
} 

最后我试图通过诉讼合并，这里是它。

@IBAction func margeTest(_ sender: Any) { 
    let videoUrl = videoUrlforMarge[0] 
    let url = NSURL(fileURLWithPath: videoUrl.absoluteString!!) 
    let audio = audioUrl[0] 
    let urla = NSURL(fileURLWithPath: audio.absoluteString!!) 

    self.mergeFilesWithUrl(videoUrl: url , audioUrl: urla) 
} 

我在栈溢出一些代码，但得到了这个错误。

Answer 1

确保您aVideoAsset.tracks(withMediaType: AVMediaTypeVideo)阵列和aAudioAsset.tracks(withMediaType: AVMediaTypeAudio)数组访问位置由索引数组中之前的一些价值，附加保护可以帮你这个

guard aVideoAsset.tracks(withMediaType: AVMediaTypeVideo).count > 0 && aAudioAsset.tracks(withMediaType: AVMediaTypeAudio) > 0 else{ 
      return 
     } 

let aVideoAssetTrack : AVAssetTrack = aVideoAsset.tracks(withMediaType: AVMediaTypeVideo)[0] 
let aAudioAssetTrack : AVAssetTrack = aAudioAsset.tracks(withMediaType: AVMediaTypeAudio)[0] 

另外，还要确保您videoUrlforMarge阵列和audioUrl阵列存取位置由索引阵列中之前有一定的价值，使用相同的程序

由这一个

取代您mergeTest动作代码

@IBAction func margeTest(_ sender: Any) { 

     guard videoUrlforMarge.count > 0 && audioUrl.count > 0 else{ 
      return 
     } 

     let videoUrl = videoUrlforMarge[0] 
     let url = NSURL(fileURLWithPath: videoUrl.absoluteString!!) 
     let audio = audioUrl[0] 
     let urla = NSURL(fileURLWithPath: audio.absoluteString!!) 

     self.mergeFilesWithUrl(videoUrl: url , audioUrl: urla) 
    } 

我的回答会不会帮你为什么是你的阵列EMPTY问题但可以帮助你不死机这一点，也许这个问题是由用于初始化您aVideoAsset和aAudioAsset造成的网址

更新

试试这个办法让你savePathUrl工作

let filename = "temp.mp4" 
    let documentsURL = URL(fileURLWithPath: NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!) 
    let savePath = documents.appendingPathComponent(fileName).path 
    let savePathUrl = URL(fileURLWithPath: savePath)