As you can see I use 2 filesrcs and 2 matroskademuxs. What am
I doing wrong in the first pipeline? Is this possible to do
with only 1 filesrc/demux ?
Yes, but you need to have queues after the matroskademux src pads as
otherwise you have a single thread driving 2 pads and it will lead
to a deadlock. Adding the queues will make sure each branch has its
own thread running.