Docker for opencv 3.4.5 with python and ffmpeg. I created this because the ones I found were opencv 3.4.2, and I needed some things in 3.4.5.
The hard work of creating this is from https://hub.docker.com/r/valian/docker-python-opencv-ffmpeg . I changed the version changed to 3.4.5 (rather than 3.4.2). In turn, valian's docker file references: https://www.learnopencv.com/install-opencv3-on-ubuntu/
In addition, I updated the version of gcc / g++ in the docker to 7.