[Interest] qcamera resolution issue

[Lopes Yoann]

Yes the backend is DirectShow. You can find the code in "qtmultimedia/src/plugins/directshow/camera".
Changing the preview resolution is simply not implemented, it's of course technically possible.

Your solution using directly DirectShow doesn't work because a QWidget embedded in a QGraphicsProxyWidget cannot be controlled externally, the proxy doesn't have a window handle.
You could try having the QWidget behind the QDeclarativeView instead of using QGraphicsProxyWidget. The QDeclarativeView should have no background and you should make sure nothing is painted at the location the QWidget is. You'll see the camera widget through the QDeclarativeView.

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Yoann