本文內容：

1、播放本地視頻，實時添加濾鏡，修改不同的濾鏡效果

2、給本地視頻添加濾鏡，然后保存有濾鏡效果的視頻到本地

1、播放本地視頻，實時添加濾鏡，修改不同的濾鏡效果

/**
 播放視頻，實時添加濾鏡
 */
- (void)playVideo{

    NSURL *sampleURL = [[NSBundle mainBundle]URLForResource:@"demo" withExtension:@"mp4" subdirectory:nil];
    
    /**
     *  初始化 movie
     */
    _movie = [[GPUImageMovie alloc] initWithURL:sampleURL];
    
    /**
     *  是否重復播放
     */
    _movie.shouldRepeat = NO;
    
    /**
     *  控制GPUImageView預覽視頻時的速度是否要保持真實的速度。
     *  如果設為NO，則會將視頻的所有幀無間隔渲染，導致速度非?？?。
     *  設為YES，則會根據視頻本身時長計算出每幀的時間間隔，然后每渲染一幀，就sleep一個時間間隔，從而達到正常的播放速度。
     */
    _movie.playAtActualSpeed = YES;
    
    /**
     *  設置代理 GPUImageMovieDelegate，只有一個方法 didCompletePlayingMovie
     */
    _movie.delegate = self;
    
    /**
     *  This enables the benchmarking mode, which logs out instantaneous and average frame times to the console
     *
     *  這使當前視頻處于基準測試的模式，記錄并輸出瞬時和平均幀時間到控制臺
     *
     *  每隔一段時間打印： Current frame time : 51.256001 ms，直到播放或加濾鏡等操作完畢
     */
    _movie.runBenchmark = YES;
    
    /**
     *  添加卡通濾鏡
     */
    _filter = [[GPUImageToonFilter alloc] init];
    [_movie addTarget:_filter];
    
    /**
     *  添加顯示視圖
     */
    
    [_filter addTarget:self.filterView];
    
    [self.view addSubview:_filterView];
    
    /**
     *  視頻處理后輸出到 GPUImageView 預覽時不支持播放聲音，需要自行添加聲音播放功能
     *
     *  開始處理并播放...
     */
    [_movie startProcessing]; 
}

/**
 切換濾鏡效果,切換頻繁會有卡頓，可異步

 @param index index
 */
- (void)switchCameraFilter:(NSInteger)index {
    [_movie removeAllTargets];
    switch (index) {
        case 0:
            _filter = [[GPUImageBilateralFilter alloc] init];
            break;
        case 1:
            _filter = [[GPUImageHueFilter alloc] init];
            break;
        case 2:
            _filter = [[GPUImageColorInvertFilter alloc] init];
            break;
        case 3:
            _filter = [[GPUImageSepiaFilter alloc] init];
            break;
        case 4: {
            _filter = [[GPUImageGaussianBlurPositionFilter alloc] init];
            [(GPUImageGaussianBlurPositionFilter*)_filter setBlurRadius:40.0/320.0];
        }
            break;
        case 5:
            _filter = [[GPUImageMedianFilter alloc] init];
            break;
        case 6:
            _filter = [[GPUImageVignetteFilter alloc] init];
            break;
        case 7:
            _filter = [[GPUImageKuwaharaRadius3Filter alloc] init];
            break;
        default:
            _filter = [[GPUImageBilateralFilter alloc] init];
            break;
    }
    [_movie addTarget:_filter];
    if (self.filterView != nil) {
        [self.filterView removeFromSuperview];
    }
    [_filter addTarget:self.filterView];
    [self.view addSubview:self.filterView];
}

2、給本地視頻添加濾鏡，然后保存有濾鏡效果的視頻到本地

/**
 不播放視頻，視頻添加濾鏡直接保存本地
 */
- (void)saveVideo {
    NSURL *sampleURL = [[NSBundle mainBundle]URLForResource:@"demo" withExtension:@"mp4" subdirectory:nil];
    
    // 初始化 movie
    _movie = [[GPUImageMovie alloc] initWithURL:sampleURL];
    _movie.shouldRepeat = NO;
    _movie.playAtActualSpeed = YES;
    
    // 設置加濾鏡視頻保存路徑
    NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Movie.mp4"];
    unlink([pathToMovie UTF8String]);
    NSURL *movieURL       = [NSURL fileURLWithPath:pathToMovie];
    
    // 初始化
    _writer = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(480, 640)];
    _writer.encodingLiveVideo = NO;
    _writer.shouldPassthroughAudio = NO;
    
    /**
     如果你設置了 _movie.audioEncodingTarget = _writer;
     會報如下錯誤：
     *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[AVAssetWriterInput appendSampleBuffer:] Cannot append sample buffer: Input buffer must be in an uncompressed format when outputSettings is not nil'
     暫時沒去深究，以后再解決！
     */
    
    // 添加濾鏡
    GPUImageToonFilter *filter = [[GPUImageToonFilter alloc] init];
    [_movie addTarget:filter];
    [filter addTarget:_writer];
    
    [_movie enableSynchronizedEncodingUsingMovieWriter:_writer];
    [_writer startRecording];
    [_movie startProcessing];
    
    __weak typeof(self) weakSelf = self;
    
    [_writer setCompletionBlock:^{
        NSLog(@"OK");
        
        [filter removeTarget:weakSelf.writer];
        [weakSelf.writer finishRecording];
    }];

demo：https://github.com/chjwrr/LocalVideoAddFilter