ios - GPUImage:取消 GPUImageMovieWriter

Question

在运行startRecording 和startProcessing 之后，有什么方法可以取消/停止GPUImageMovieWriter 和GPUImageMovie 吗？

Answer 1

最近，GPUImageMovie 中添加了一个新方法，允许取消对视频文件的处理:

- (void)cancelProcessing;

这将允许您有效地取消对视频的处理，不再处理更多的帧。

请考虑到您的 GPUImageMovieWriter 的 completionBlock 无论如何都会被调用，因此您应该有某种标志来检查调用该 block 是为了成功完成还是通过取消。

下面是一些示例代码:

- (void)processVideo
{
    _wasCancelled = NO;

    self.imageMovie = [self createImageMovie];
    self.filter = [self createFilter];
    [imageMovie addTarget:filter]
    self.movieWriter = [self createMovieWriter];

    [self.movieWriter startRecording];
    [self.imageMovie startProcessing];

    [self.movieWriter setCompletionBlock:^{
        [self.filter removeTarget:movieWriter];
        [self.movieWriter finishRecording];

        if (!_wasCancelled) {
            // Do stuff with the video
        }
    }];
}

- (void)cancelVideoProcessing
{
    _wasCancelled = YES;
    [self.imageMovie cancelProcessing];
}