I suppose it's ffmpeg's issue. Can you send the sample from Arte to ffmpeg's developers ?
I doubt it : the errors buffers in VDR seems more relevant to me.
why do you think that the messages like
Aug 15 13:19:08 vdr vdr: [24729] buffer usage: 70% (tid=24728) Aug 15 13:19:08 vdr vdr: [24729] buffer usage: 60% (tid=24728)
are the erorrs buffers in VDR ?