How to processing multiple camera/video by a filter in qml/qt?

Unique66

I have multiple Camera/video and i want to processing all concurrently by a unique filter (QAbstractVideoFilter) . I need show processed frame results separately too. It means that my filterFrame should know about each frame that have send by different Camera/video. how to implement this idea ? i think i have to send a parameter to filter from each VideoOutput like code below but how to do that ?

MediaPlayer {
       id: mediaPlayer1
       source: "video1.mp4"
   }
VideoOutput {
       id: videoOutput1
       source: mediaPlayer1
       filters: [FilterFrame](parameterVideo1)
}
————————
MediaPlayer {
       id: mediaPlayer2
       source: "video2.mp4"
   }
VideoOutput {
       id: videoOutput2
       source: mediaPlayer2
       filters: [FilterFrame](parameterVideo1)
}

GrecKo

You can't do that with a QAbstractVideoFilter

The solution would be to instantiate multiple QAbstractVideoFilter and link them to your own object doing the processing.

MultipleVideoProcessor {
    id: videoProcessor
}
MediaPlayer {
    id: mediaPlayer1
    source: "video1.mp4"
}
VideoOutput {
    id: videoOutput1
    source: mediaPlayer1
    filters: CustomVideoFilter {
        processor: videoProcessor
        parameter: "video1"
    }
}
————————
MediaPlayer {
    id: mediaPlayer2
    source: "video2.mp4"
}
VideoOutput {
    id: videoOutput2
    source: mediaPlayer2
    filters: CustomVideoFilter {       
        processor: videoProcessor       
        parameter: "video2"
     }
}

The filterRunnables of the filters will just proxy the frame to the actual processor, giving it an additional parameter.
Something like this:

void CustomVideoFilterRunnable::run(QVideoFrame *input, const QVideoSurfaceFormat &surfaceFormat, QVideoFilterRunnable::RunFlags flags)
{
    m_processor->run(input, surfaceFormat, flags, m_parameter);
}

Unique66

something is not clear for me in your sample code, please explain little more about where i can access to (parameter: "video1") in filter class, and where and how i implement MultipleVideoProcessor class in relation to CustomVideoFilter ? because i need multiple threads to run each video in filters. thanks again

GrecKo

please explain little more about where i can access to (parameter: "video1") in filter class

You declare a new type in C++ inheriting from QAbstractVideoFilter with a processor Q_PROPERTY with your processor class as a type, a parameter Q_PROPERTY (or multiple) with whatever you need as a type and expose it to QML.

how i implement MultipleVideoProcessor class in relation to CustomVideoFilter ? because i need multiple threads to run each video in filters.

Like in my example, you declare a function similar to QAbstractVideoFilter::run but with the parameters you need for each video in addition.
The threading should be handled by the multimedia framework, meaning that your different Filter run methods will be called in different threads. Just make sure your Processor class is thread safe.

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