These requirements [[https://github.com/get-iplayer/get_iplayer/wiki/installation|do change quite frequently]].

ffmpeg is back in Stretch:

  apt-get install perl libwww-perl libxml-perl libxml-simple-perl libmojolicious-perl atomicparsley ffmpeg
  
and

  crontab -e
  
  min hour day/month month day/week command
  15 0 * * * /usr/local/bin/get_iplayer --pvr --quiet -c 'echo "$(date)    <name> <episode>" >> /home/slack/log/iplayer' 2>> /tmp/get_iplayer.log
  
Download:

  mkdir src && cd src
  gcl https://github.com/get-iplayer/get_iplayer.git

As root:

  ln -s /home/slack/src/get_iplayer/get_iplayer /usr/local/bin/