QML Video Object does not use alpha channel of video



  • I have a video with an alpha channel that i would like to overlay onto other elements (another video).

    However, qt doesn't seem to respect the alpha channel, and instead ignores it so that i get a huge black background instead. As you can imagine, this is not ideal.

    My platform is Windows 7, running under the MinGW compiler, if this makes a difference? (though in all honesty, it is just a qml file i am running with the scene-viewer).

    Is this a bug report that needs filing? and if so, how do i go about doing that / what section is it relevant for?

    Thanks!



  • I would bet this was done for performance reasons and they don't consider it a bug. It's much slower to have to transfer data pixel by pixel checking the alpha channel than just a bulk memory copy.



  • Well surely they could have an optional flag that you can set to use the alpha channel, so that if you don't want it then you still have the improved speed?


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