Tensorflow==1.13.2 installation issues on raspberry pi 4b & raspbian lite

I use a raspberry pi 4 2gb ram. With Raspbain lite.
tensorflow==1.13.2 . The wheel is not available for all platforms.
so, tried to install tensorflow from source, there is an error I don´t understand. ‘Package ‘ffmpeg’ has no insstallation candidate.’
I tried to install ffmpeg from source but this didn´t help.
anyone can help me?

installation script:
image

please see below:
image