How to convert RAW Bayer GRBG to RGB8 using Nvidia VPI3 in C programming language

Accelerated Computing GPU-Accelerated Libraries
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1 
#include <opencv2/opencv.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/core/cuda.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include <fstream>

#include <vpi/OpenCVInterop.hpp>
  
#include <vpi/Image.h>
#include <vpi/Stream.h>
#include <vpi/algo/ConvertImageFormat.h>

using namespace std;
using namespace cv;

Mat readRawImage(const string& filename, int width, int height) {
    // Open the raw file in binary mode
    FILE* file = fopen(filename.c_str(), "rb");
    if (!file) {
        cerr << "Error opening file: " << filename << endl;
        return Mat();
    }

    // Calculate the size of the image
    int imageSize = width * height;

    // Read the raw data into a buffer
    vector<uchar> buffer(imageSize);
    fread(buffer.data(), sizeof(uchar), buffer.size(), file);

    if (!file) {
        cerr << "Error reading file: " << filename << endl;
        return cv::Mat();
    }

    fclose(file);

    // Create a Mat object from the buffer
    // CV_8UC1 indicates an 8-bit single-channel image (grayscale)
    Mat image(height, width, CV_8UC1);
    memcpy(image.data, buffer.data(), buffer.size());

    return image;
}

int main(int argc, char *argv[])
{
    if (argc != 2)
    {
        cerr << "Must pass an input image to be blurred" << endl;
        return 1;
    }
    
    Mat cvImage = readRawImage(argv[1], 2048, 1216);

    if (cvImage.empty()) {
        cerr << "Failed to load image." << endl;
        return -1;
    }

    VPIStatus status;
     

    cout << "Width: " << cvImage.cols << endl;
    cout << "Height: " << cvImage.rows << endl;
    cout << "Channels: " << cvImage.channels() << endl;


    VPIStream stream;
    vpiStreamCreate(0, &stream);
    
    VPIImage inputImage, outputImage;
    Mat cvOut(cvImage.rows, cvImage.cols, CV_8UC3, Scalar(255, 255, 255));

    VPIImageFormat inputImageFormat = VPI_MAKE_RAW_IMAGE_FORMAT(VPI_RAW_BAYER_RGGB, VPI_MEM_LAYOUT_PITCH_LINEAR,
                                               VPI_DATA_TYPE_UNSIGNED, VPI_SWIZZLE_X000,
                                               1, VPI_PACKING_X8);
    //inputImageFormat = vpiImageFormatSetColorSpec(inputImageFormat, VPI_COLOR_SPEC_sRGB);
    
    status = vpiImageCreate(cvImage.cols, cvImage.rows, inputImageFormat, VPI_BACKEND_CUDA, &inputImage);
    cout << "VPI InputImage : " << status << endl;

    status = vpiImageCreateWrapperOpenCVMat(cvImage, 0 , &inputImage);
    cout << "Opencv Wrapper : " << status << endl;

    
    status = vpiImageCreate(cvImage.cols, cvImage.rows, VPI_IMAGE_FORMAT_RGB8, 0, &outputImage);
    cout << "Create output VPIImage status: " << status << endl;

    status = vpiSubmitConvertImageFormat(stream, VPI_BACKEND_CUDA, inputImage, outputImage, NULL);
    cout << "Conversion status: " << status << endl;

    VPIImageFormat outputFormat;
    status = vpiImageGetFormat(outputImage, &outputFormat);
    cout << "Ouput format status: "<< status << endl;

    vpiStreamSync(stream);

    VPIImageData outputData;
    status = vpiImageLockData(outputImage, VPI_LOCK_READ, VPI_IMAGE_BUFFER_HOST_PITCH_LINEAR, &outputData);

    cout << "Output data status: " << status << endl;

    status =  vpiImageDataExportOpenCVMat(outputData, &cvOut);

    cout << "CV Output status: " << status <<  endl;
    
    //const VPIImageBufferPitchLinear &outPitch = outputData.buffer.pitch;
  
    //Mat cvOut3(outPitch.planes[0].height, outPitch.planes[0].width, CV_8UC3, outPitch.planes[0].data,
    //                      outPitch.planes[0].pitchBytes);

    cout << "Width: " << cvOut.cols << endl;
    cout << "Height: " << cvOut.rows << endl;
    cout << "Channels: " << cvOut.channels() << endl;

    
    vpiImageUnlock(outputImage);
    imwrite("out.jpg", cvOut);
    vpiImageDestroy(inputImage);
    vpiImageDestroy(outputImage);
    vpiStreamDestroy(stream);
    return 0;
}
  • Not able to generate RGB image with this code, please anyone suggest what is wrong with the code