[Serge Dumoulin]

Hello Dan, thanks for replying. I forgot to reply that i got an answer on another forum.
here is the command that is in fact working. Pretty impressive command:

-filter_complex “[0:a:0]pan=1c|c0=0.5*c0+0.5*c1[left];[0:a:1]pan=1c|c0=0.5*c0+0.5*c1[right];[left][right]amerge[a]” -map 0:v -map “[a]” -c:v copy -c:a pcm_s16le

Serge