iphone - 保存太长的录制视频时，应用程序崩溃

Question

问题:

当保存在我的应用程序中录制的视频时，如果视频大小/持续时间太大/太长，我的应用程序会崩溃而不会出现日志/异常。

我的设置:

在我的应用程序中，我使用 UIImagePickerController 来录制视频。现在我注意到，如果我制作的视频长度非常长(例如，使用 UIImagePickerControllerQualityTypeMedium 时 30 分钟，或使用 UIImagePickerControllerQualityTypeIFrame1280x720 时超过一分钟)，在保存视频时，应用程序会崩溃。有时有警告，有时没有警告。现在我开始调试并注意到它与内存有关(malloc_error)。

我使用探查器实时检查分配，并注意到当它要保存视频时，分配突然变得非常大(我猜与视频的临时内存使用有关？)，然后它最终崩溃了。这是探查器的屏幕截图:

该应用必须能够录制最长 1 小时的视频(以任何指定的质量)。

我尝试过的:

• 设置 picker.videoMaximumDuration 更短/更长
• 使用分析器/仪器进行调试
• 检查是否有泄漏
• 关闭设备上所有打开的应用程序并删除应用程序(用于存储清理)以获取更多内存

代码:

- (void)openCamera:(id)sender context:(NSManagedObjectContext*)context {
    self.context = context;
    //Set self as delegate (UIImagePickerControllerDelegate)
    [self.picker setDelegate:self];
    //If the device has a camera
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        self.picker.sourceType = UIImagePickerControllerSourceTypeCamera;
        self.picker.allowsEditing = YES;
        self.picker.videoQuality = [Settings videoQualitySetting];
        //If the camera can record video 
        NSString *desired = (NSString *)kUTTypeMovie;
        if ([[UIImagePickerController availableMediaTypesForSourceType:self.picker.sourceType] containsObject:desired]) {
            //Let the user record video
            self.picker.mediaTypes = [NSArray arrayWithObject:desired];
            self.picker.videoMaximumDuration = MaxDuration;
        }
        else {
            NSLog(@"Can't take videos with this device"); //debug
        }
        //Present the picker fullscreen/in popover
        if ([Settings shouldDisplayFullScreenCamera]){
            [self presentModalViewController:self.picker animated:YES];
            [self.masterPopoverController dismissPopoverAnimated:YES];
        }
        else {
            if (!_popover){
                _popover = [[UIPopoverController alloc] initWithContentViewController:self.picker];
            }
            [_popover presentPopoverFromBarButtonItem:sender permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
        }
    }
    else {
        NSLog(@"Does not have a camera"); //debug
    }    
}

以及在选择图像时的代码:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
    {
    NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType];

    // Save the video, and close the overlay
    if (CFStringCompare ((__bridge CFStringRef) mediaType, kUTTypeMovie, 0)
        == kCFCompareEqualTo) {

        self.tempVideoPath = [[info objectForKey:
                                UIImagePickerControllerMediaURL] path];
        [LocalVideoStorage saveVideo:[NSData dataWithContentsOfPath:self.tempVideoPath name:self.videoName];
        [_picker dismissModalViewControllerAnimated: YES];
        [[_picker parentViewController] dismissModalViewControllerAnimated:YES];
        [_popover dismissPopoverAnimated:YES];  
    }
}

最后，当它被保存时:

+ (NSString*)saveVideo:(NSData*)video:(NSString*)videoName {
    NSFileManager *fileManager = [NSFileManager defaultManager];//create instance of NSFileManager

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); //create an array and store result of our search for the documents directory in it

    NSString *documentsDirectory = [paths objectAtIndex:0]; //create NSString object, that holds our exact path to the documents directory

    NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.MOV", videoName]]; //add our video to the path

    [fileManager createFileAtPath:fullPath contents:video attributes:nil]; //finally save the path (video)

    NSLog(@"Video saved!");
    return fullPath;

}

我在 iOS 5.1.1 上使用 ARC

更新:我在 malloc_error_break 上设置了一个断点，在仪器中我可以看到它是从以下位置调用的:

#   Address Category    Timestamp   Live    Size    Responsible Library Responsible Caller
0   0x10900000  Malloc 473,29 MB    02:08.951.332   •   496283648   Foundation  -[NSData(NSData) initWithContentsOfFile:]

解决方案:正如 lawicko & john.k.doe 所说，我试图将视频从它的路径加载到 NSData 变量中。这导致整个视频被加载到内存中。而不是这样做，我现在只是移动文件(并重命名)copyItemAtPath

NSError *error = nil;
if (![fileManager copyItemAtPath:path toPath:fullPath error:&error])
    NSLog(@"Error: %@", error);

Answer 1

你的问题是这一行:

[NSData dataWithContentsOfPath:self.tempVideoPath]

你显然是想一次加载这个文件的内容到内存，但 iOS 永远不会让你一次加载那么多。您的 saveVideo 方法似乎只将文件从临时位置复制到文档目录。如果这是你唯一需要做的事情，那么看看 copyItemAtPath:toPath:error NSFileManager 的方法。您可以更改 saveVideo 方法以将临时文件路径而不是数据作为参数。