How do I get rid of ffmpeg `WARNING: library configuration mismatch` message?
Solution 1:
To fix this remove the following package:
sudo apt remove libavcodec-ffmpeg-extra56
Apt will remove the package and replace it with libavcodec-ffmpeg56 resulting in ffmpeg no longer output a warning message.
For details on libavcodec-ffmpeg-extra56 package and why it is likely no needed, see: https://askubuntu.com/a/847566/8570
Solution 2:
On Ubuntu 18.04:
sudo apt remove libavcodec-extra57