[Multimedia] create QVideoFrame for YUV420p

[Vi67]

Hello,

I'm making a bridge between OpenTok (video call library) and Qt, for mobile platforms only (Android & iOS).
It works fine on Android, now I'm working on iOS part.

The pixel format used is YUV420p (i450)
But it looks like I get only Y plane, because at the end the image is visible but green like this > https://i.imgur.com/FzLx2Cc.jpg

I have 3 planes for each Y U V, then I concat them, then I send buffer to Qt.

Objective-C part (almost like C++) :

- (void)renderVideoFrame:(OTVideoFrame*) frame
{
    __block OTVideoFrame *frameToRender = frame;
    dispatch_sync(self.renderQueue, ^{
        
        uint8_t* y = (uint8_t*)[frameToRender.planes pointerAtIndex:0];
        uint8_t* u = (uint8_t*)[frameToRender.planes pointerAtIndex:1];
        uint8_t* v = (uint8_t*)[frameToRender.planes pointerAtIndex:2];
        
        // concat Y U V
        size_t pixelNb = frameToRender.format.imageHeight * frameToRender.format.imageWidth;
        size_t pSize = pixelNb * sizeof(uint8_t);
        uint8_t* buffer = (uint8_t*)malloc(pixelNb * sizeof(uint8_t) * 6);
        memcpy(buffer, y, pSize*4);
        memcpy(buffer+pSize*4, u, pSize);
        memcpy(buffer+pSize*5, v, pSize);
        
        QVideoFrame::PixelFormat pixelFormat = QVideoFrame::Format_YUV420P; // correspond to i420
        
        // C++ call
        TokHandler::instance()->newFrame(self._id, buffer, frameToRender.format.imageWidth, frameToRender.format.imageHeight, frame.format.imageWidth, pixelFormat);
    });
}

In Qt (C++) I create QFrame like this :

void TokHandler::newFrame(int _id, uint8_t* buffer, int width, int height, int bpl, QVideoFrame::PixelFormat format)
{
    QByteArray bytes(reinterpret_cast<const char*>(buffer), bpl*height);

    QVideoFrame frame(new QMemoryVideoBuffer(bytes, bpl), QSize(width, height), format);
    frame.setStartTime(0);

    TokHandler::instance()->getRenderer(_id)->newFrame(frame);
}

An idea ? Thanks