在不显示UIVideoEditorController的情况下修剪视频？

Question

目前我正在处理一个处理视频的应用程序.在我的应用程序中,用户可以修剪视频,我有一个自定义控件,用于选择开始时间和结束时间.我需要通过这两个值修剪视频.我尝试过UIVideoEditorController如下.

    UIVideoEditorController* videoEditor = [[[UIVideoEditorController alloc] init] autorelease];
    videoEditor.delegate = self;
    NSString* videoPath = [[NSBundle mainBundle] pathForResource:@"test" ofType:@"MOV"];
    if ( [UIVideoEditorController canEditVideoAtPath:videoPath] )
    {
      videoEditor.videoPath = videoPath;
      [self presentModalViewController:videoEditor animated:YES];
    }
    else
    {
      NSLog( @"can't edit video at %@", videoPath );
    }

但问题是上面的代码会显示苹果的视频编辑器控件,用户可以对该视图进行一些操作.我不想显示此视图,因为我已经显示了视频MPMoviePlayer并接收了用户输入(开始时间和结束时间)以在自定义控件上修剪视频.如何在不显示视频的情况下修剪视频UIVideoEditorController？

Answer 1

最后我找到了解决方案.

我们可以AVAssetExportSession用来修剪视频而不显示UIVideoEditorController.

我的代码是这样的:

- (void)splitVideo:(NSString *)outputURL
{

    @try
    {
        NSString *videoBundleURL = [[NSBundle mainBundle] pathForResource:@"Video_Album" ofType:@"mp4"];

        AVAsset *asset = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:videoBundleURL] options:nil];

        NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:asset];

        if ([compatiblePresets containsObject:AVAssetExportPresetLowQuality])
        {

            [self trimVideo:outputURL assetObject:asset];

        }
        videoBundleURL = nil;

        [asset release];
        asset = nil;

        compatiblePresets = nil;
    }
    @catch (NSException * e)
    {
        NSLog(@"Exception Name:%@ Reason:%@",[e name],[e reason]);
    }
}

此方法修剪视频

- (void)trimVideo:(NSString *)outputURL assetObject:(AVAsset *)asset
  {

    @try
    {

        AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]initWithAsset:asset presetName:AVAssetExportPresetLowQuality];

        exportSession.outputURL = [NSURL fileURLWithPath:outputURL];

        exportSession.outputFileType = AVFileTypeQuickTimeMovie;

        CMTime start = CMTimeMakeWithSeconds(splitedDetails.startTime, 1);

        CMTime duration = CMTimeMakeWithSeconds((splitedDetails.stopTime - splitedDetails.startTime), 1);

        CMTimeRange range = CMTimeRangeMake(start, duration);

        exportSession.timeRange = range;

        exportSession.outputFileType = AVFileTypeQuickTimeMovie;

        [self checkExportSessionStatus:exportSession];

        [exportSession release];
        exportSession = nil;

    }
    @catch (NSException * e)
    {
        NSLog(@"Exception Name:%@ Reason:%@",[e name],[e reason]);
    }
}

此方法检查修剪的状态:

- (void)checkExportSessionStatus:(AVAssetExportSession *)exportSession
  {

    [exportSession exportAsynchronouslyWithCompletionHandler:^(void)
    {

        switch ([exportSession status])
            {

            case AVAssetExportSessionStatusCompleted:

                NSLog(@"Export Completed");
                break;

            case AVAssetExportSessionStatusFailed:

                NSLog(@"Error in exporting");
                break;

            default:
                break;

        }
    }];
}

我splitVideo从导出按钮操作方法调用方法,并将输出URL作为参数传递.