使用cv::cvtColor转yuv420sp到rgb有哪些

使用cv::cvtColor将YUV420SP转换为RGB可以有以下几种方式：

1. 使用COLOR_YUV2RGB_NV21或COLOR_YUV2RGB_NV12

cv::Mat yuvMat = cv::imread("input.jpg", cv::IMREAD_UNCHANGED);
cv::Mat rgbMat;

cv::cvtColor(yuvMat, rgbMat, cv::COLOR_YUV2RGB_NV21); // 或者使用 cv::COLOR_YUV2RGB_NV12

cv::imwrite("output.jpg", rgbMat);

2. 使用COLOR_YUV2BGR_NV21或COLOR_YUV2BGR_NV12，然后使用cv::cvtColor将BGR转换为RGB

cv::Mat yuvMat = cv::imread("input.jpg", cv::IMREAD_UNCHANGED);
cv::Mat bgrMat, rgbMat;

cv::cvtColor(yuvMat, bgrMat, cv::COLOR_YUV2BGR_NV21); // 或者使用 cv::COLOR_YUV2BGR_NV12
cv::cvtColor(bgrMat, rgbMat, cv::COLOR_BGR2RGB);

cv::imwrite("output.jpg", rgbMat);

3. 自己实现转换函数，参考下面的代码

void YUV420SP_to_RGB888(const unsigned char* yuv, unsigned char* rgb, int width, int height)
{
    int frameSize = width * height;
    int chromaSize = frameSize / 4;

    const unsigned char* yData = yuv;
    const unsigned char* uvData = yuv + frameSize;

    for (int j = 0; j < height; j++) {
        int yOffset = j * width;
        int chromaOffset = (j / 2) * width / 2;
        for (int i = 0; i < width; i++) {
            int Y = yData[yOffset + i];
            int V = uvData[chromaOffset + i / 2] - 128;
            int U = uvData[frameSize + chromaOffset + i / 2] - 128;

            int R = Y + 1.402 * V;
            int G = Y - 0.344 * U - 0.714 * V;
            int B = Y + 1.772 * U;

            R = R < 0 ? 0 : (R > 255 ? 255 : R);
            G = G < 0 ? 0 : (G > 255 ? 255 : G);
            B = B < 0 ? 0 : (B > 255 ? 255 : B);

            int index = (j * width + i) * 3;
            rgb[index] = R;
            rgb[index + 1] = G;
            rgb[index + 2] = B;
        }
    }
}

cv::Mat yuv420sp_to_rgb(const unsigned char* yuv, int width, int height)
{
    cv::Mat rgbMat(height, width, CV_8UC3);
    unsigned char* rgbData = rgbMat.data;

    YUV420SP_to_RGB888(yuv, rgbData, width, height);

    return rgbMat;
}