ios - GPUImageMovie 在应用滤镜时暂停

Question

我正在使用 Brad Larson 的优秀图书馆 GPUImage为我的申请。目前我遇到了一个问题。我的应用程序捕获 10 秒的视频，然后允许应用 filter。在 GPUImageMovie 中应用 filters 时，我无法暂停播放并应用新的 filter 以便视频不从头开始连续播放.

我看到一个开放的 github 问题 here .如果有人遇到类似问题并找到解决方案，请发布您的答案。提前致谢。

Answer 1

经过多次搜索和尝试，我终于解决了这个问题。我们需要使用 AVPlayerItem 而不是 URL 来启动 GPUImageMovie。我从 here 得到了这个有值(value)的线索.

我正在发布我目前在我的应用程序中使用的代码，它按预期工作。但是在 iPod 6.1 中存在性能问题，我正在研究相同的增强功能。

设置GPUImageMovie的初始方法，

- (void)setupVideo
{
    playerItem = [[AVPlayerItem alloc]initWithURL:self.recordSession.outputUrl];
    player = [AVPlayer playerWithPlayerItem:playerItem];

    movieFile = [[GPUImageMovie alloc] initWithPlayerItem:playerItem];

    movieFile.runBenchmark = YES;
    movieFile.playAtActualSpeed = YES;
    [self.view sendSubviewToBack:self.videoView];

    [movieFile addTarget:filter];
    [filter addTarget:self.videoView];

    [movieFile startProcessing];
    movieRunning = YES;

    dispatch_async(dispatch_get_main_queue(), ^{
        self.playButton.hidden = YES;
    });

    player.rate = 1.0;
}

当用户点击过滤器按钮时调用此方法。

- (void)filterClicked:(UIButton *)button
{
    // Set paused time. If player reaches end of the video, set pausedTime to 0.
    if (CMTIME_COMPARE_INLINE(pausedTime, !=,  player.currentItem.asset.duration)) {
        pausedTime = player.currentTime;
    } else {
        pausedTime = CMTimeMake(0, 600.0);
    }
    [self.videoView setBackgroundColor:[UIColor clearColor]];

    [movieFile cancelProcessing];

    switch (button.tag)
    {
    case 0:
        filter = [[GPUImageFilter alloc] init];
        break;
    case 1:
        filter = [[GPUImageColorInvertFilter alloc] init];
        break;
    case 2:
        filter = [[GPUImageEmbossFilter alloc] init];
        break;
    case 3:
        filter = [[GPUImageGrayscaleFilter alloc] init];
        break;
    default:
        filter = [[GPUImageFilter alloc] init];
        break;
    }

    [self filterVideo];

}

过滤器生成后，视频播放恢复在此方法中处理。

- (void)filterVideo {

    // AVPlayerItem is initialized with required url

    playerItem = [[AVPlayerItem alloc]initWithURL:self.outputUrl]; 
    [player replaceCurrentItemWithPlayerItem:playerItem];

    //GPUImageMovie is initialized with AVPlayerItem

    movieFile = [[GPUImageMovie alloc] initWithPlayerItem:playerItem];

    movieFile.runBenchmark = YES;
    movieFile.playAtActualSpeed = YES;

    // Adding targets for movieFile and filter

    [movieFile addTarget:filter];
    [filter addTarget:self.videoView]; // self.videoView is my GPUImageView

    [movieFile startProcessing];
    movieRunning = YES;

    dispatch_async(dispatch_get_main_queue(), ^{
        self.playButton.hidden = YES;
    });

    // Player rate is set to 0 means player is paused

    [player setRate:0.0];

    // Seeking to the point where video was paused

     if (CMTIME_COMPARE_INLINE(pausedTime, !=, player.currentItem.asset.duration)) {
        [player seekToTime:pausedTime];
    }
    [player play];
}