捕捉相機和音頻輸入時出錯

Question

使用iOS4中的一些漂亮的新API，我試圖從iPhone的相機和麥克風捕捉輸入並將其保存到文件中。下面是我使用的代碼。

AVCaptureSession* captureSession = [[AVCaptureSession alloc] init]; 
AVCaptureDevice *audioCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio]; 
AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioCaptureDevice error:&error]; 
AVCaptureDeviceInput* videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:captDevice error:&error]; 
AVCaptureMovieFileOutput * videoOutput = [[AVCaptureMovieFileOutput alloc] init]; 

if (videoInput && videoOutput && audioInput) 
{ 
    [captureSession addInput:audioInput]; 
    [captureSession addInput:videoInput]; 
    [captureSession addOutput:videoOutput]; 
    if([captDevice lockForConfiguration:&error]) 
    { 
     if ([captDevice hasTorch]) 
      captDevice.torchMode = AVCaptureTorchModeOn; 

     [captDevice unlockForConfiguration]; 
    } 
    else 
    { 
     NSLog(@"Could not lock device for config error: %@", error); 
    } 

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 

    NSURL* saveLocationURL = [[NSURL alloc] initFileURLWithPath:[NSString stringWithFormat:@"%@/movie.mov", documentsDirectory]]; 

    [videoOutput startRecordingToOutputFileURL:saveLocationURL recordingDelegate:self]; 
    [captureSession startRunning]; 

    [saveLocationURL release]; 
} 
else 
{ 
    NSLog(@"Video Error: %@", error); 
} 

當didFinishRecordingToOutputFileAtURL回來時，我得到一個神祕的錯誤響應。

Error Domain=AVFoundationErrorDomain Code=-11803 "Cannot Record" UserInfo=0x152f70 {NSLocalizedRecoverySuggestion=Try recording again., AVErrorRecordingSuccessfullyFinishedKey=false, NSLocalizedDescription=Cannot Record} 

錯誤代碼-11803表示「AVErrorSessionNotRunning」。我所能說的只是告訴我一些我不知道的事情。任何人都知道爲什麼會議沒有運行？

Answer 1

在[videoOutput startRecordingToOutputFileURL:saveLocationURL recordingDelegate:self];之前致電[captureSession startRunning];。