How to use the setMetadata(key,value) method in QtMultimidia CameraCapture QML Type? - qt

Question

I'm interested in setting GPS location metadata to captured images in QML. I noticed the setMetadata(key,value) method in several qml capture elements but I can't understand how it works, or find any examples.
The definition in the documentation states:
"Sets a particular metadata key to value for the subsequent image
captures."
http://qt-project.org/doc/qt-5/qml-qtmultimedia-cameracapture.html
Does the method work? if so, please place a simple example.
If not, is there any other way to set (or edit) image metadata (even if use of C++ is necessary) in Qt?
Update (but not solved):
I've tried the following code, the app runs on desktop takes the picture and saves it. After I open it up with Preview (MAC) and check the metadata... and nothing special there (no comment key).
Camera {
id: camera
captureMode: Camera.CaptureStillImage
Component.onCompleted: {
imageCapture.setMetadata("Comment","My Picture")
}
imageCapture {
resolution: "640x480"
onImageCaptured: {
console.log("Image Captured Callback : Preview : "+preview)
}
onImageSaved: {
console.log("Image Saved Callback : Save Path : "+path)
}
onImageMetadataAvailable: {
console.log("Image Metadata Callback : "+key+" = "+value)
}
}
}

Answer 1

I think you should use a subset of the keys documented here before you start the capture.
edit
FWIW, here is a minimal test on Ubuntu, Qt 5.3 - I created an empty application, added a menu command, the camera and viewer
import QtQuick 2.2
import QtQuick.Controls 1.1
import QtQuick.Window 2.0
import QtMultimedia 5.0
ApplicationWindow {
title: qsTr("Hello World")
width: 640
height: 480
menuBar: MenuBar {
Menu {
title: qsTr("File")
MenuItem {
text: qsTr("Exit")
onTriggered: Qt.quit();
}
MenuItem {
text: qsTr("Capture")
onTriggered: {
camA.imageCapture.setMetadata("Description", "my comment")
camA.imageCapture.captureToLocation("/home/carlo/Pictures/x.jpg")
}
}
}
}
Camera { id : camA }
VideoOutput { source: camA }
}
and the result seems ok...