wger also supports adding videos to the exercises and are served locally like the images.

If you just want to mirror/download the files from, just do:

python download-exercise-videos

If you want to upload your own videos to your instance, it is recommended that you install the ffmpeg package both in the system and in the virtualenv. Without this, no validation can be performed during upload and the video metadata wont be saved to the database. Due to the size of this package and its dependencies, they are not installed by default:

$ apt-get install ffmpeg
$ pip install ffmpeg-python