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标题: c++ - 将 CMSampleBufferRef 转换为 cv::Mat [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-12 10:06
标题: c++ - 将 CMSampleBufferRef 转换为 cv::Mat

我正在尝试将 CMSampleBufferRef(作为 iOS 中 AVCaptureVideoDataOutputSampleBufferDelegate 的一部分)转换为 OpenCV Mat，以尝试半实时地稳定输出。

我正在运行一个测试应用程序，紧接着 this ，但在我创建和使用 Mat 时不断遇到问题。

Swift Controller

let wrapper : OpenCVWrapper = OpenCVWrapper()
...
func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
    self.wrapper.processBuffer(sampleBuffer, self.previewMat)
}

OpenCVWrapper

- (void)processBufferCMSampleBufferRef)buffer UIImageView*)previewMat {
    // Convert current buffer to Mat
    CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(buffer);
    CVPixelBufferLockBaseAddress( pixelBuffer, 0);

    CGFloat bufferWidth = CVPixelBufferGetWidth(pixelBuffer);
    CGFloat bufferHeight = CVPixelBufferGetHeight(pixelBuffer);

    unsigned char *pixel = (unsigned char *)CVPixelBufferGetBaseAddress(pixelBuffer);

    Mat tmp(bufferWidth, bufferHeight, CV_8UC4, pixel);
    Mat cur = tmp.clone();

    dispatch_async(dispatch_get_main_queue(), ^{
        [previewMat setImage:[UIImage imageWithCVMat:cur]];
    });
    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
}

在 Mat cur = tmp.clone() 中，我得到一个 EXC_BAD_ACCESS

对我在这里做错了什么有什么想法吗？

我试过 bufferWidth 和 CGFloat 和 int，并在 Mat 的构造函数中切换它们，同样的问题。

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Best Answer-推荐答案

改进的解决方案解决了“只有前 30%”的问题:

- (cv::Mat)matFromBufferCMSampleBufferRef)buffer {
    CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(buffer);
    CVPixelBufferLockBaseAddress( pixelBuffer, 0 );

    //Processing here
    int bufferWidth = (int)CVPixelBufferGetWidth(pixelBuffer);
    int bufferHeight = (int)CVPixelBufferGetHeight(pixelBuffer);
    unsigned char *pixel = (unsigned char *)CVPixelBufferGetBaseAddress(pixelBuffer);

    //put buffer in open cv, no memory copied
    cv::Mat mat = cv::Mat(bufferHeight,bufferWidth,CV_8UC4,pixel,CVPixelBufferGetBytesPerRow(pixelBuffer));

    //End processing
    CVPixelBufferUnlockBaseAddress( pixelBuffer, 0 );

    cv::Mat matGray;
    cvtColor(mat, matGray, CV_BGR2GRAY);

    return matGray;
}

关于c++ - 将 CMSampleBufferRef 转换为 cv::Mat，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34677890/

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