The total weight of the Kannelle application includes all your videos plus all your group elements (logos, jingles, music), etc. The more groups and video projects you have in your company account, the more storage space the application will take up.
In order of size, at installation, the weight of Kannelle (with 1 group) and no project yet created is about 200 MB (100 MB for the application itself and 100 MB for the logos, intros, outros and fonts of your group).