There is much suspicious code left. This plugin needs to be fixed if it
is still used.

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

Close #10111

This should fix meta-data expansion in LibVLC (i.e. when recording).

(The unlikely corner case of ENOMEM remains unhandled/unfixed.)

This really only depends on the input item(s) and the core.