QCamera reports no support for QCamera::CaptureVideo mode



  • I am trying to work with Qt 5.0.1 using a ViewFinder and to capture video from a webcam similar to that of the Camera multimedia example. Both in my application AND in the Camera example, the Camera device returns FALSE to camera->IsCaptureModeSupported(QCamera::CaptureVideo); I have tried a few different webcams including the built-in one on my Asus laptop. I have MANY encoding codecs installed but they also come back from:
    qDebug() << "Supported video codecs:" << recorder->supportedVideoCodecs(); and
    qDebug() << "No. of supported video codecs:" << recorder->supportedVideoCodecs().count();
    Showing Zero available codecs. The documentation is not at all clear as to what this means, is it a codec problem that prevents the capture mode from being supported or the other way around? There is also no documentation on what PlugIns (if any) are needed to support capture of video on Windows or Linux platforms. I suspect there are some to support using video codecs but its not clear and I have tried to build the WMV plugin and AVFoundation but both fail to build with unfound Interface errors.
    Detailed suggestions and information would be greatly appreciated.



  • Hi ProfRivkin.

    Sorry to ask you that first but is your webcam working with standard video programs?
    Do you have the correct access rights?

    I would start with mpeg1 or mpeg2. Those codecs are definitely supported by ffmpeg and gstreamer.
    Is the statndard video Qt example working?



  • As I said, there are no codecs being reported by Qt even though they are installed and usable by other programs, and yes, I can Viewfinder and even capture an image to a PNG file in a Qt app, but only capturing streaming video is "not supported".



  • Yes streaming is always the mainproblem. I'm not quite sure but QCamera will also use either ffmpeg or gstreamer under the hood to stream a video.

    In a Qt4.8project we used ffmpeg directly.
    I have to check the QCamera class by my self.

    Good luck.



  • i have same problem , my application not supporting capture video mode , i have tested app using many different webcam but still facing same problem , can anybody help me for this to capture video in qt . is there any setting or any plugins that i have to add .


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