应用过滤器时GPUImageMovie暂停

问题描述

我正在为我的应用程序使用Brad Larson的优秀图书馆。目前我遇到了一个问题。我的应用程序捕获10秒视频，然后允许过滤申请。在 GPUImageMovie 中应用过滤器时，我无法暂停播放并应用新的过滤器这样视频就会连续播放而不从头开始。

I am using Brad Larson's great library GPUImage for my application. Currently I am stuck with an issue. My application captures 10 second videos and after that allows filter applying. While applying filters in GPUImageMovie, I am not able to pause the play and apply new filter so that video will play continuously without starting from the beginning.

我看到一个开放的github问题。如果有人遇到类似问题并找到解决方案，请发布您的答案。在此先感谢。

I saw an open github issue here. If anyone faced similar issue and found a solution, please post your answers. Thanks in advance.

推荐答案

最后我在经过太多搜索后修复此问题并尝试。我们需要使用AVPlayerItem而不是URL来启动GPUImageMovie。我从获得了这个有价值的线索。

And finally I fixed this after too many searches and try. We need to initiate GPUImageMovie with AVPlayerItem instead of URL. I got this valuable clue from here.

我发布了我目前在我的应用程序中使用的代码，它正在按预期工作。但iPod 6.1中存在性能问题，我正在研究相同的增强功能。

I am posting my code which I am currently using in my application and it is working as expected. But there are performance issues in iPod 6.1 and I am working on enhancements of the same.

设置GPUImageMovie的初始方法，

Initial method to setup GPUImageMovie,

- (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，会调用此方法。

This method is called when user clicks on a filter button.

- (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];

}

生成过滤器后，使用此方法处理视频播放恢复。

After filter generation, video play resume is handled in this method.

- (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];
}

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