AVCaptureMovieFileOutput NSInvalidArgumentException没有活动/启用连接

Question

我偶尔会遇到NSInvalidArgumentException异常，当我开始在viewController中录制视频时，但只有在先前的视图控制器中拍摄照片后。我尝试了Google和So的一些建议，但仍然在拨打startRecordingToOutputFileURL:fileURL时遇到此错误。

如果我不访问拍摄照片的其他视图控制器，我就不会收到错误 - 它只发生在拍照时，然后切换到进行视频录制的新视图控制器。

我认为拍摄照片时留下了一些残留物，但是当我初始化我的视频录像机视图控制器时，我无法设置会话和其他内容。任何想法正在发生什么或如何从中恢复？为什么是NSInvalidArgumentException异常？谢谢！

这里是我的代码：

dispatch_async(dispatch_get_main_queue(), ^{ 

      // Try to Fix bug: 
      // http://stackoverflow.com/questions/5979962/error-while-recording-video-on-iphone-using-avfoundation 

      [self.captureSession beginConfiguration]; 

      // Ensure session is running 
      if ([self.captureSession isRunning] == NO) { 
       NSLog(@"Capture session is NOT running... Starting it now!"); 
       [self.captureSession startRunning]; 
      } 
      else { 
       NSLog(@"Capture session is ALREADY running..."); 
      } 

      NSLog(@"File URL is: %@",fileURL); 
      NSLog(@"FileOutput is: %@",self.fileOutput); 

      [self.fileOutput startRecordingToOutputFileURL:fileURL recordingDelegate:self]; 

      // Try to Fix bug: 
      // http://stackoverflow.com/questions/5979962/error-while-recording-video-on-iphone-using-avfoundation 
      [self.captureSession commitConfiguration]; 

     }); 

以下是错误回溯：

2014-05-18 16:01:38.818 app[1699:60b] *** Start recording 
2014-05-18 16:01:38.820 app[1699:60b] Capture session is ALREADY running... 
2014-05-18 16:01:38.827 app[1699:60b] Capture session is ALREADY running... 
2014-05-18 16:01:38.828 app[1699:60b] File URL is: file:////var/mobile/Applications/73FFC590-05A8-4D74-82D9-EBA122B00A20/Documents/2014-05-18-16-01-38-0.mp4 
2014-05-18 16:01:38.828 app[1699:60b] FileOutput is: <AVCaptureMovieFileOutput: 0x16513b10> 
2014-05-18 16:01:38.829 app[1699:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[AVCaptureMovieFileOutput startRecordingToOutputFileURL:recordingDelegate:] - no active/enabled connections.' 
*** First throw call stack: 
(0x2fe5ff0b 0x3a5f6ce7 0x2ed5751d 0xfb4b5 0x3aadfd53 0x3aadfd3f 0x3aae26c3 0x2fe2a681 0x2fe28f4d 0x2fd93769 0x2fd9354b 0x34d006d3 0x326f2891 0xe40c9 0x3aaf4ab7) 
libc++abi.dylib: terminating with uncaught exception of type NSException 

这是captureSession如何初始化（从开源项目位置：https://github.com/shu223/SlowMotionVideoRecorder）：

- (id)initWithPreviewView:(UIView *)previewView { 

    self = [super init]; 

    if (self) { 

     NSError *error; 

     self.captureSession = [[AVCaptureSession alloc] init]; 
     self.captureSession.sessionPreset = AVCaptureSessionPresetInputPriority; 

     AVCaptureDevice *videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; 
     AVCaptureDeviceInput *videoIn = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error]; 

     if (error) { 
      NSLog(@"Video input creation failed"); 
      return nil; 
     } 

     if (![self.captureSession canAddInput:videoIn]) { 
      NSLog(@"Video input add-to-session failed"); 
      return nil; 
     } 
     [self.captureSession addInput:videoIn]; 


     // save the default format 
     self.defaultFormat = videoDevice.activeFormat; 
     defaultVideoMaxFrameDuration = videoDevice.activeVideoMaxFrameDuration; 


     AVCaptureDevice *audioDevice= [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio]; 
     AVCaptureDeviceInput *audioIn = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:&error]; 
     [self.captureSession addInput:audioIn]; 

     self.fileOutput = [[AVCaptureMovieFileOutput alloc] init]; 
     [self.captureSession addOutput:self.fileOutput]; 


     self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession]; 
     self.previewLayer.frame = previewView.bounds; 
     self.previewLayer.contentsGravity = kCAGravityResizeAspectFill; 
     self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill; 
     [previewView.layer insertSublayer:self.previewLayer atIndex:0]; 

     [self.captureSession startRunning]; 
    } 
    return self; 
} 

我的代码在viewDi中使用了这样的初始化代码DLOAD：

self.captureManager = [[AVCaptureManager alloc] initWithPreviewView:self.view]; 
self.captureManager.delegate = self; 

实际启动和停止记录从一个IBAction为方法，这样做的代码：

- (IBAction)recButtonTapped:(id)sender { 

    // REC START 
    if (self.captureManager.isRecording == NO) { 

     NSLog(@"*** Start recording"); 

     // change UI 
     [self.recBtn setImage:self.recStopImage 
        forState:UIControlStateNormal]; 
     self.fpsControl.enabled = NO; 

     // timer start 
     startTime = [[NSDate date] timeIntervalSince1970]; 
     self.timer = [NSTimer scheduledTimerWithTimeInterval:0.01 
                 target:self 
                selector:@selector(timerHandler:) 
                userInfo:nil 
                repeats:YES]; 

     [self.captureManager startRecording]; 

    } 
    // REC STOP 
    else { 

     NSLog(@"*** Stop recording"); 

     isNeededToSave = YES; 
     [self.captureManager stopRecording]; 

     [self.timer invalidate]; 
     self.timer = nil; 

     // change UI 
     [self.recBtn setImage:self.recStartImage 
        forState:UIControlStateNormal]; 
     self.fpsControl.enabled = YES; 

    } 
} 

编辑 - 我肯定在图片浏览会议结束时，这里是代码。我确认它在离开照片视图控制器时被调用。

 NSLog(@"RELEASE PHOTO SESSION NOW!"); 

     for(AVCaptureInput *input1 in _mySesh.inputs) { 
      [_mySesh removeInput:input1]; 
     } 

     for(AVCaptureOutput *output1 in _mySesh.outputs) { 
      [_mySesh removeOutput:output1]; 
     } 


     [_mySesh stopRunning]; 

     // Fix closing of session 
     dispatch_after(
         dispatch_time(0,500000000), 
         dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), 
         ^{ 
          _mySesh = nil; 
         } 

     ); 

UPDATE #####

根据下面唯一的答案，我想“取消链接”的前开始录音文件。它仍然没有工作。

NSURL *fileURL = [NSURL URLWithString:[@"file://" stringByAppendingString:filePath]]; 

    //NSLog(@"Beginning to record to output file..."); 

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{ 

     // Wait for session to start 
     //[NSThread sleepForTimeInterval:1.0]; 

     dispatch_async(dispatch_get_main_queue(), ^{ 

      // Ensure session is running 
      if ([self.captureSession isRunning] == NO) { 
       NSLog(@"Capture session is NOT running... Starting it now!"); 
       [self.captureSession startRunning]; 
      } 
      else { 
       NSLog(@"Capture session is ALREADY running..."); 
      } 

      NSLog(@"File URL is: %@",fileURL); 
      NSLog(@"FileOutput is: %@",self.fileOutput); 

      // Delete the file 
      unlink([[@"file://" stringByAppendingString:filePath] UTF8String]); 

      [self.fileOutput startRecordingToOutputFileURL:fileURL recordingDelegate:self]; 

     }); 

    }); 

UPDATE

只是为了子孙后代，我打电话了“didFinishRecordingToOutputFileAtURL”委托方法：

- (void)     captureOutput:(AVCaptureFileOutput *)captureOutput 
    didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL 
         fromConnections:(NSArray *)connections error:(NSError *)error 
{ 

    // Print any errors 
    if (error) { 
     NSLog(@"Error Recording Video! %@",error.localizedDescription); 
    } 

    _isRecording = NO; 

    if ([self.delegate respondsToSelector:@selector(didFinishRecordingToOutputFileAtURL:error:)]) { 
     [self.delegate didFinishRecordingToOutputFileAtURL:outputFileURL error:error]; 
    } 

} 

Answer 1

从我所看到的，这是由于已经存在的文件。

尝试删除你的电话之前，文件startRecordingToOutputFileURL:： [[NSFileManager defaultManager] removeItemAtPath:fileURL]; 你可以仔细检查： [[NSFileManager defaultManager] fileExistsAtPath:fileURL];

If a file at the given URL already exists when capturing starts, recording to the new file will fail.

可能导致崩溃的另一件事是，如果你不具备委托方法实施。

它需要实现： captureOutput:didFinishRecordingToOutputFileAtURL:fromConnections:error:

，因为这是唯一可靠的地方得到的输出。

另一种可疑的东西：

当您创建fileURL，你做

NSURL *fileURL = [NSURL URLWithString:[@"file://" stringByAppendingString:filePath]]; 

您可以更改到

NSURL *fileURL = [NSURL fileURLWithPath:filePath]; 

并确保filePath是有效的。

从文档：This method throws an NSInvalidArgumentException if the URL is not a valid file URL.所有的

Answer 2

首先，先启动AVCaptureSession。之后，您可以创建AVPreviewLayer和AVCaptureMovieFileOutput。

其次，使用-[AVCaptureSession canAddOutput:]和-[AVCaptureSession canAddInput:]在向捕获会话添加任何内容之前，这将为您节省大量时间和挫败感。第三，只需要beginConfiguration和commitConfiguration，当你想要一次性更改captureSession中的很多东西时，例如，你只需要使用beginConfiguration和commitConfiguration。删除输入，更改预设。如果要实施它，它对前/后摄像头切换很有用。在这些呼叫之间开始或停止会话不是bueno。

Answer 3

尝试评论self.captureSession.sessionPreset = ...行，看看是否有帮助。它为我制造了诡计。问题的原因是我试图捕获最高质量和FOV的照片，但使用此设置时，当我试图捕捉视频时，出现“无活动/启用连接”的例外情况。