QT6 Using QVideoSink with QCamera to process every frame

Question

I`m digging example qt6 6.2.2 camera.pro and found next line code:

m_captureSession.setVideoOutput(ui->viewfinder);

this is the way of outing frames to ui.

I know what QVideoSinc is used for grab every frame and process it.

I have replaced this line with m_captureSession.setVideoSink(&videoSink);

where videoSinc defined as my class :

class MyVideoSinc : public QVideoSink
{
    Q_OBJECT
public:
    bool videoframeReady=false;
    MyVideoSinc()
    {
        connect(this, &QVideoSink::videoFrameChanged, this, &MyVideoSinc::hvideoFrameChanged);
    }
public Q_SLOTS:

    void hvideoFrameChanged(const QVideoFrame &frame)
    {
        videoframeReady=true;
    }
};

hvideoFrameChanged raised for every frame in Windows build, but only once in Android application.

What is wrong here. How to grab and process frames from QCamera in QT6 ? I don`t want show frames with ui->viewfinder. I need processing frames myself.

Answer 1

I made a small repository to show how to process frames with QVideoSink in Qt6. Have a look at it.

I use such approach in my own applications, I tested it on Android 9, all works like a charm.

But be careful, on Linux from launch to launch FPS can differ very much, sometimes FPS are normal, but very often FPS are very-very low - 1 FPS only. This is a bug Qt6, 6.2.3 affected still. Have a look at the bug.