ios - GPUImage：取消 GPUImageMovieWriter

Question

有什么方法可以取消/停止GPUImageMovieWriter和GPUImageMovie运行startRecording后startProcessing？

Answer 1

最近，添加了一种新方法GPUImageMovie，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，并且不再处理任何帧。

考虑到您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该块是为成功完成还是被取消调用。

这是一些示例代码：

- (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];
}

Answer 2

为什么。有一个取消录制选项。

[self.movieWriter cancelRecording];

如果视频以任何方式中断，则不会保存视频。

Answer 3

假设 self.movi​​eWriter 为 GPUImageMovieWriter，则需要在调用 startRecording 和 startProcessing 之前设置回调：

[self.movieWriter setCompletionBlock:^{
    [self finishFilter];
}];

然后你可以停止图像处理：

[self.movieWriter endProcessing];

回调是：

- (void)finishFilter {
    //remove all targets from your filter chain calling "removeAllTargets"
    //then:
    [self.movieWriter finishRecording];
    self.movieWriter.completionBlock = nil;
    self.movieWriter = nil;
}