Qt's multimedia demo does not work ."qtmultimedia/examples/multimedia/video/qmlvideofx"

I try to run Qt Multimedia demo "qtmultimedia/examples/multimedia/video/qmlvideofx".
GStreamer also report error "No URI".

I check Qt demo's code. And I do a modify, the demo can work now.
Modify qtmultimedia/examples/multimedia/video/qmlvideofx/qml/qmlvideofx/Content.qml
function openVideo(path)

{ console.log("[qmlvideofx] Content.openVideo \"" + path + "\"") stop() contentLoader.source = "ContentVideo.qml" videoFramePaintedConnection.target = contentLoader.item contentLoader.item.mediaSource = "file://" + path // add file:// contentLoader.item.volume = volume contentLoader.item.play() console.log("start play"); updateSource() }

Qt put all the qml into *.qrc. So we need add "file://" when we want to use a resource.