Question

我在Video recorder API中遇到了videoMaximumDuration属性的奇怪问题。我试图解决这个问题超过一个星期，但不能。我发布了几个论坛，但还没有帮助。

我使用以下代码从我的应用程序启动Camera并开始录制视频。根据我的要求，我应该设置录制视频的持续时间。因此，我使用“videoMaximumDuration”属性来设置录制视频的持续时间。

if ([types containsObject:(id)kUTTypeMovie])
{
    appDelegate.pickerController = [[UIImagePickerController alloc] init];
    appDelegate.pickerController.delegate = self;
    appDelegate.pickerController.videoQuality = setVideoQuality;

       appDelegate.pickerController.allowsEditing = NO;
    appDelegate.pickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
    appDelegate.pickerController.showsCameraControls = YES;
    appDelegate.pickerController.navigationBarHidden = YES;
    appDelegate.pickerController.toolbarHidden = YES;
    appDelegate.pickerController.wantsFullScreenLayout = YES;
    appDelegate.pickerController.cameraViewTransform =
    CGAffineTransformScale(appDelegate.pickerController.cameraViewTransform,
                           CAMERA_TRANSFORM_X,
                           CAMERA_TRANSFORM_Y);
    appDelegate.pickerController.mediaTypes = [NSArray arrayWithObject:(id)kUTTypeMovie];
    appDelegate.pickerController.videoMaximumDuration = maxDuration;
    [self presentModalViewController:appDelegate.pickerController animated:YES];
}

问题在于：

如果我将videoQuality设置为UIImagePickerControllerQualityTypeHigh，则持续时间（videoMaximumDuration）按预期工作，即完全停止记录视频的持续时间。如果我去看相册中的录制视频，以确保它，它按时间记录良好。如果我将videoQuality更改为UIImagePickerControllerQualityTypeMedium（或）UIImagePickerControllerQualityTypeLow，那么视频录制的持续时间（videoMaximumDuration）无法按预期工作，即它能够在设置的持续时间内自动停止视频录制，没有问题，但如果我去看相册中的录制视频以确保，它不是按照所花费的时间，而是我可以看到更小视频比我录制的。例如，如果我将videoMaximumDuration设置为30秒，则在录制视频后，如果我去看相册中的录制视频，它可以记录=仅22秒。似乎是API本身的问题。当我将视频质量用作UIImagePickerControllerQualityTypeHigh时，这种情况不会发生。

我甚至尝试使用自定义叠加视图，并通过设置计时器（NStimer）来启动和停止通过以下代码录制视频。但我仍然看到同样的问题已经发现。

    overlay = [[OverlayView alloc]initWithFrame:CGRectMake(0, 0, 768, 1024)];

if ([types containsObject:(id)kUTTypeMovie])
{
    appDelegate.pickerController = [[UIImagePickerController alloc] init];
    appDelegate.pickerController.delegate = self;
    appDelegate.pickerController.videoQuality = setVideoQuality;

   appDelegate.pickerController.allowsEditing = NO;
    appDelegate.pickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
    appDelegate.pickerController.showsCameraControls = NO;
    appDelegate.pickerController.navigationBarHidden = YES;
    appDelegate.pickerController.toolbarHidden = YES;
    appDelegate.pickerController.wantsFullScreenLayout = YES;
    appDelegate.mTimerSelectionForVideo = maxDuration; // TIME SET HERE IN VARIABLE
    appDelegate.pickerController.cameraViewTransform =
    CGAffineTransformScale(appDelegate.pickerController.cameraViewTransform,
                           CAMERA_TRANSFORM_X,
                           CAMERA_TRANSFORM_Y);
    appDelegate.pickerController.mediaTypes = [NSArray arrayWithObject:(id)kUTTypeMovie];
    appDelegate.pickerController.videoMaximumDuration = maxDuration;
    [self presentModalViewController:appDelegate.pickerController animated:YES];  
    appDelegate.pickerController.cameraOverlayView =overlay;
}

OverlayView.m

    -(void)startAction:(id)sender
{
    BOOL bStop = TRUE;

    void (^hideControls)(void);
    hideControls = ^(void) {
        cameraSelectionButton.alpha = 0;
        startButton.enabled = NO;
        lbl.hidden = NO;
    };

    void (^recordMovie)(BOOL finished);
    recordMovie = ^(BOOL finished) {
        stopButton.enabled = YES;
        [appDelegate.pickerController startVideoCapture];
    };

    // Hide controls
    [UIView  animateWithDuration:0.3 delay:0.0 options:UIViewAnimationOptionCurveEaseInOut animations:hideControls completion:recordMovie];

    if ( appDelegate.mTimerSelectionForVideo==0 )
    {
        bStop = FALSE;
    }
    if ( bStop )
        timer = [NSTimer scheduledTimerWithTimeInterval:(appDelegate.mTimerSelectionForVideo)+1 
                                             target:self selector:@selector(stopCamera:) userInfo:nil repeats:NO];
}
- (void)stopCamera:(NSTimer *)theTimer
{
    startButton.enabled = YES;

    if ( timer )
    {
        [timer invalidate];
        timer = nil;    
    }    
    [appDelegate.pickerController stopVideoCapture];
    [appDelegate.pickerController dismissModalViewControllerAnimated:YES];
}

但我仍然看到同样的问题。为什么其他视频质量设置无法按照videoMaximumDuration设置工作？我在iPhone 4.1和iPad 4.3上测试过，同样的问题已被观察到。看起来，问题是API或录像机硬件本身支持它。

如果有可能（或）根据您的经验，有人可以帮我解决这个问题吗？

提前谢谢你！

Answer 1

通过在摄像机视图顶部创建叠加视图并通过代码处理开始/停止来修复它。

iPhone：视频录制器API中的videoMaximumDuration属性存在奇怪问题

1 个答案: