ios - GPUImage から GPUImageMovieComposition をどのように使用しますか?

Question

GPUImageMovieComposition を GPUImageMovieWriter ( GPUImage から)で使用する方法がわかりません。使用方法の例はありますか?

これが私が試したことです。コンポジション、videoComposition、およびaudioMixが有効であることをテストしました:

movieFile = [[GPUImageMovieComposition alloc] initWithComposition:composition andVideoComposition:videoComposition andAudioMix:audioMix];
filter = [[GPUImagePixellateFilter alloc] init];

[movieFile addTarget:filter];

GPUImageView *filterView = (GPUImageView *)self.view;
[filter addTarget:filterView];

NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Movie.m4v"];
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];

movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(640.0, 480.0)];
[filter addTarget:movieWriter];

movieWriter.shouldPassthroughAudio = YES;
movieFile.audioEncodingTarget = movieWriter;
[movieFile enableSynchronizedEncodingUsingMovieWriter:movieWriter];

[movieWriter startRecording];
[movieFile startProcessing];

[movieWriter setCompletionBlock:^{
    [filter removeTarget:movieWriter];
    [movieWriter finishRecording];
}];

前もって感謝します！