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Details

Type: Bug
Resolution: Done
Priority: P1: Critical
Fix Version/s: 5.9.5
Affects Version/s: 5.9.0, 5.9.1
Component/s: Multimedia, QML: Declarative and Javascript Engine, Quick: Core Declarative QML
Labels:
None
Environment:
Windows

Description

We have tested the YUV Format on QML VideoOutput with an QAbstractVideoSurface.The picture 'yuyv_source.png' is a screenshot of the source QVideoFrame and the 'yuyv_QVideoOutput.png' is a screenshot of the VideoOutput. There you can see a huge different in the quality of the image, where the QT rendering is pretty bad. In our application we need the YUV Rendering, because it is much faster an need les cpu performance, as the conversion from YUV in RGB on CPU. But with this quality the YUV rendering capability ist not useful.

// C++
QAbstractVideoSurface* m_videoSurface;

m_surfaceFormat = QVideoSurfaceFormat(QSize(bmiHeader.biWidth,
                                            bmiHeader.biHeight),
                                      QVideoFrame::Format_YUYV,
                                      QAbstractVideoBuffer::NoHandle);
             m_surfaceFormat.setScanLineDirection(QVideoSurfaceFormat::TopToBottom);                m_surfaceFormat.setYCbCrColorSpace(QVideoSurfaceFormat::YCbCr_xvYCC709);

QAbstractVideoSurface* ANTCapCamDevice::videoSurface() const
{
    return m_videoSurface;
}

void ANTCapCamDevice::setVideoSurface(QAbstractVideoSurface* surface)
{
    if((m_videoSurface != surface) &&
       (m_videoSurface) &&
       (m_videoSurface->isActive()))
    {
        m_videoSurface->stop();
    }
    m_videoSurface = surface;
}

void ANTCapCamDevice::onVideoFrameAvailable(QVideoFrame frame)
{
    /** Variablen **/
    /** Start **/

    if(m_videoSurface != NULL)
    {
        m_videoSurface->present(frame);
    }

   // video.yuyv shown at http://rawpixels.net
   // video.yuyv is the source image (yuyv_source.png) 
   QFile file;
   file.setFileName(QLatin1String("C:\\video.yuyv"));
   file.open(QIODevice::ReadWrite|QIODevice::Truncate);

   frame.map(QAbstractVideoBuffer::ReadOnly);
   file.write((char*)frame.bits(),frame.width()*frame.height()*2);
   frame.unmap();
}

void ANTCapCamDevice::startPreview()
{
    /** Variablen **/
    /** Start **/

    // Start surface
    putDebug << "Start VideoSurface" << m_videoSurface;
    putDebug << "VideoSurfaceFormat:" << m_surfaceFormat;

    if(m_videoSurface->isActive()) {m_videoSurface->stop();}

    if((m_videoSurface->start(m_surfaceFormat)) != true)
    {
        // Error
    }
    /** Ende **/
}

// QML
// screenshot from VideoOutput is the image (yuyv_QVideoOutput.png) 

VideoOutput {
   id: videoOutput_livestream

   width: (resizingOfLive)?(parent.width):(sourceRect.width)
   height: (resizingOfLive)?(parent.height):(sourceRect.height)

   anchors.centerIn: parent
   visible: true

   fillMode: VideoOutput.PreserveAspectFit

   source = classHandle.camDeviceListModel.get(activeCameraIndex).videoOutput
}