// Der gesamte Code sieht gut aus, aber die Zeilen von movieWriter - setCompletionBlock werden nicht kompiliert. Weiß nicht, wo das Problem liegt.

Ich habe versucht, es seit den letzten 3 Tagen zu lösen, aber es funktioniert nicht.

-(IBAction)setBrightness:(id)sender
{    
    sleep(1);

    NSURL *sampleURL = [NSURL URLWithString:_videoURLPath];
    movieFile = [[GPUImageMovie alloc] initWithURL:sampleURL];
    movieFile.runBenchmark = YES;
    movieFile.playAtActualSpeed = NO;

    filterView = (GPUImageView *)gpuView;
    filter=[[GPUImageBrightnessFilter alloc]init];
    [movieFile addTarget:filter];
    [filter addTarget:filterView];

    [(GPUImageBrightnessFilter *)filter setBrightness:brightValue];

    unlink([pathToMovie UTF8String]); // If a file already exists, AVAssetWriter won't let you record new frames, so delete the old movie

    NSURL *movieURL = [NSURL fileURLWithPath:pathToMovie];enter code here

    movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(320.0, 320.0)];
    [filter addTarget:movieWriter];

    movieWriter.shouldPassthroughAudio = NO;
    movieFile.audioEncodingTarget = movieWriter;
    [movieFile enableSynchronizedEncodingUsingMovieWriter:movieWriter];

    [movieWriter startRecording];
    [movieFile startProcessing];

    [movieWriter setCompletionBlock:^{

        [filter removeTarget:movieWriter];
        [movieWriter finishRecording];

        dispatch_async(dispatch_get_main_queue(), ^{

            [_toolDelegate stringPathOfFilteredVideoFromTool:pathToMovie];
            [self.navigationController popViewControllerAnimated:YES];

        });
    }];
}