Filter perms
  Set permissions for the output video frame.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
perms AVOptions:
  mode              <int>        ..FVA.... select permissions mode (from 0 to 4) (default none)
     none            0            ..FVA.... do nothing
     ro              1            ..FVA.... set all output frames read-only
     rw              2            ..FVA.... set all output frames writable
     toggle          3            ..FVA.... switch permissions
     random          4            ..FVA.... set permissions randomly
  seed              <int64>      ..FVA.... set the seed for the random mode (from -1 to UINT32_MAX) (default -1)


