I know this is an old post
What is "an old post"? This is a brand new thread.

Your error messages indicate that you aren't linking whatever library or other binary that contains the VlcQmlPlayer class implementation into your program. It could also be the case that MOC has not been run on the VlcQmlPlayer class to generate the metaobject code.

Check you qmake project file to make sure you are linking to the library that contains the Vlc code.