(In reply to comment #6)
> (In reply to comment #5)
> > You have to enable VDPAU output as well.
> 
> Sorry, but where and how?
> In VLC?
> *.conf file?
>

In preferences go to the "Video" tab and select VDPAU from the list of outputs.

> > If you don't do that, in case the
> > readback method is used,
> 
> I read something about it.
> Can I disable 'readback method' as interrims solution?
>

No, you can't disable it, it is required for non-VDPAU outputs.

> > it won't work because the necessary format
> > conversions have not been implemented yet (I'm working on it).
> 
> Go ahead ;-)

It's already finished, try this patch series:
http://lists.freedesktop.org/archives/mesa-dev/2013-October/046014.html

With that, readback works flawlessly.