Filter aperms
  Set permissions for the output audio frame.
    Inputs:
       #0: default (audio)
    Outputs:
       #0: default (audio)
aperms 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)

This filter has support for timeline through the 'enable' option.

