QtAV/examples/qml/multiwindow.qml

import QtQuick 2.0
import QtQuick.Window 2.0
import QtAV 1.3

Item {
    MediaPlayer { //or AVPlayer
        id: player
        source: "test.mov"
        autoPlay: true
    }
    MouseArea {
        anchors.fill: parent
        onClicked: player.play()
    }
    VideoOutput {
        anchors.fill: parent
        source: player
        width: 400
        height: 300
    }
    Window {
        x: 0; y: 100; width: 600; height: 400; visible: true
        VideoOutput {
            anchors.fill: parent
            source: player
            regionOfInterest: Qt.rect(0, 0, 0.5, 1);
        }
    }
    Window {
        x: 600; y: 100; width: 400; height: 300; visible: true
        VideoOutput {
            anchors.fill: parent
            source: player
            regionOfInterest: Qt.rect(0.5, 0, 0.5, 1);
        }
    }
}