GPUImageMovie pause while applying filter

Question

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

Answer 1

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.

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.

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;
}

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];

}

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];
}

Answer 2

In my case, using an AVPlayerItem was not feasible (I use compositions).

Instead I made this code:

class PausableGPUImageMovie: GPUImageMovie {
    var isPaused = false

    override func readNextVideoFrame(from readerVideoTrackOutput: AVAssetReaderOutput!) -> Bool {
        while isPaused {
            usleep(100_000)
        }
        return super.readNextVideoFrame(from: readerVideoTrackOutput)
    }
}

Very dump but feel free to improve it.