Objective-c将UIImagePickerController更改为视频模式

我有一个应用程序，我想在后台显示来自摄像机的视频源。我的viewcontroller中有以下代码：

#if !TARGET_IPHONE_SIMULATOR
    imagePickerController = [[UIImagePickerController alloc] initWithRootViewController:self];
    imagePickerController.delegate = self;
    imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;

    imagePickerController.navigationBarHidden = YES;
    imagePickerController.toolbarHidden = NO;
    imagePickerController.showsCameraControls = NO;
    //...
    [self.view addSubview:self.imagePickerController.view];
    [imagePickerController viewWillAppear:YES];
    [imagePickerController viewDidAppear:YES];
 #endif 
   //...
  [self.view addSubview:otherthings];

然后我在顶部添加其他视图，我也有声音。然而，我将imagepicker模式更改为视频模式，但当声音播放时，它会冻结。以下是我所改变的：

#if !TARGET_IPHONE_SIMULATOR
    imagePickerController = [[UIImagePickerController alloc] init];//initWithRootViewController:self];
    imagePickerController.delegate = self;
    imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;

    NSArray *mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
    NSArray *videoMediaTypesOnly = [mediaTypes filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"(SELF contains %@)", @"movie"]];
    BOOL movieOutputPossible = (videoMediaTypesOnly != nil);

    if (movieOutputPossible) {
        imagePickerController.mediaTypes = videoMediaTypesOnly;
        imagePickerController.videoQuality = UIImagePickerControllerQualityTypeHigh;
        imagePickerController.navigationBarHidden = YES;
        imagePickerController.toolbarHidden = YES;
        imagePickerController.showsCameraControls = NO;                      
    }


#endif 

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有人知道为什么当一个声音响起时，摄像头会冻结吗？顺便说一句，这声音是一个音频播放器

解决方案：使用AVFOundation而不是UIImagePickerController

    videoBackground = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 480.0)];

    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    session.sessionPreset = AVCaptureSessionPresetMedium;


    CALayer *viewLayer = videoBackground.layer;
    NSLog(@"viewLayer = %@", viewLayer);

    AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];

    captureVideoPreviewLayer.frame = videoBackground.bounds;
    [videoBackground.layer addSublayer:captureVideoPreviewLayer];

    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    NSError *error = nil;
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
    if (!input) {
        // Handle the error appropriately.
        NSLog(@"ERROR: trying to open camera: %@", error);
    }
    [session addInput:input];
    [session startRunning];
    [self.view addSubview:videoBackground];

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为什么你在alloc期间删除了rootViewController的定义？不知道，在尝试之后，它只在我播放声音时冻结。为什么？很可能你已经做了一些自动释放的事情，你应该保留自己的。具体来说，我将从以下两行开始：（NSArray*mediaTypes=）和（NSArray*videoMediaTypesOnly=）。这些都是在没有您控制的情况下自动释放的，可能会导致问题。即使我删除它们并添加imagePickerController.mediaTypes=[[NSArray alloc]initWithObjects:（NSString*）KuttypeMoine，nil]；它在播放声音时仍然会冻结。当声音结束时，相机不会解冻。我不确定我是否明白…你是说播放AVAudioPlayer声音时电影播放会冻结，然后在声音播放结束后恢复播放？