hi, I can't open gazebo recently. Dedailed description as belows:

user@host:~$gazebo
gazebo: symbol lookup error: /lib/x86_64-linux-gnu/libavfilter.so.7: undefined symbol: av_write_image_line2, version LIBAVUTIL_56

It looks like a software library version problem, but i just don't know how to fix this. my env is: ubuntu 20.04; ros noetic; gazebo 11 by default. Any suggestion is appreciated.