I was on the wrong track. Even though the library is not found this is
not the cause of the error. If I start vlc in a smaller frame (screen is
4k), something like less than 3k width, it works. If I resize the frame
to more than 3/4 of the screen width, vlc just shows a black screen
while sound still works. Strange!

Cheers,
Alex 

On Fri, Dec 10 2021, 15:24:58, Alexander Asteroth <alexander.asteroth@h-brs.de> wrote:

> Dear all,
>
> I'm trying to use vlc and ffmpeg on guix to cut mp4 files. When trying
> to play the mp4 files using vlc I encounter errors like:
>
>> Failed to open VDPAU backend libvdpau_nvidia.so: cannot open shared object file: No such file or directory
>
> In [0] it is suggested that missing compile options are the reason for
> these kind of errors might be missing compile flags (--enable...) which
> are in fact not enabled in the package specification of ffmpeg.
>
> On te ofther hand I tried to install vdpauinfo and it returns:
>
>> $ vdpauinfo 
>> display: :0   screen: 0
>> Failed to open VDPAU backend libvdpau_nvidia.so: cannot open shared object file: No such file or directory
>> Error creating VDPAU device: 1
>
> So it might be caused by missing libraries for my graphicscard.
>
> Any idea? Someone?
>
> Cheers,
>
> 	Alex
>
> ----
>
> [0] https://forum.videolan.org/viewtopic.php?p=517583