Converting a data buffer (YUV) to QImage (RGBA) - c++

Question

I'm trying to convert an image buffer with YUV data to a QImage (RGBA8888 format).
Here is the conversion from the buffer to an IplImage :
void DeckLinkCaptureDelegate::convertFrameToOpenCV(void* frameBytes, IplImage * m_RGB){
if(!m_RGB) m_RGB = cvCreateImage(cvSize(width, height), IPL_DEPTH_8U, 3);
unsigned char* pData = (unsigned char *) frameBytes;
for(int i = 0, j=0; i < width * height * 3; i+=6, j+=4)
{
unsigned char u = pData[j];
unsigned char y = pData[j+1];
unsigned char v = pData[j+2];
//fprintf(stderr, "%d\n", v);
m_RGB->imageData[i+2] = 1.0*y + 8 + 1.402*(v-128); // r
m_RGB->imageData[i+1] = 1.0*y - 0.34413*(u-128) - 0.71414*(v-128); // g
m_RGB->imageData[i] = 1.0*y + 1.772*(u-128) + 0; // b
y = pData[j+3];
m_RGB->imageData[i+5] = 1.0*y + 8 + 1.402*(v-128); // r
m_RGB->imageData[i+4] = 1.0*y - 0.34413*(u-128) - 0.71414*(v-128); // g
m_RGB->imageData[i+3] = 1.0*y + 1.772*(u-128) + 0;
}
}
The goal would be to replace IplImage * m_RGB to a QImage object. The format of the QImage can be change later with a Qt function to convert QImage format. I've managed to get a QImage from the IplImage but I'm trying to bypass this step to completely remove the IplImage step.
The problem is, I'm having a hard time understanding the code above so I don't know how I could do it for a QImage.
Could you help me do it or at least understand the code above ?
Thanks.
EDIT : Here is what I have for the moment but it's not working.
void DeckLinkCaptureDelegate::convertFrameToOpenCV(void* frameBytes, QImage m_RGB){
//if(!m_RGB) m_RGB = QImage(width, height, QImage::Format_RGB888);
unsigned char* pData = (unsigned char *) frameBytes;
for(int i = 0, j=0; i < width * height * 3; i+=6, j+=4)
{
unsigned char u = pData[j];
unsigned char y = pData[j+1];
unsigned char v = pData[j+2];
//fprintf(stderr, "%d\n", v);
m_RGB.bits()[i+2] = 1.0*y + 8 + 1.402*(v-128); // r
m_RGB.bits()[i+1] = 1.0*y - 0.34413*(u-128) - 0.71414*(v-128); // g
m_RGB.bits()[i] = 1.0*y + 1.772*(u-128) + 0; // b
y = pData[j+3];
m_RGB.bits()[i+5] = 1.0*y + 8 + 1.402*(v-128); // r
m_RGB.bits()[i+4] = 1.0*y - 0.34413*(u-128) - 0.71414*(v-128); // g
m_RGB.bits()[i+3] = 1.0*y + 1.772*(u-128) + 0;
}
}

Answer 1

Create another unsigned char array(say pDataRGB), convert yuv(pData) into rgb(pDataRGB), and then create QImage like-
QImage *m_RGB = new QImage(pDataRGB, width, height, QImage::Format_RGB888);
If you want to use only Qimage then setPixel data as following:-
m_RGB->setPixel(i, j, qRgb(r, g, b));