subtitleeditor and GStreamer plugins missing

After installing subtitleeditor, I tried to open a video to edit, and got the following error message:

See: #115: Subtitle editing software
In the above ticket, I struggled for a long time before figuring out which packages needed to be installed to get rid of the above error. I have now documented in this wiki (link above) the names of the proper packages.

Still:

1) First, there is a packaging problem. The dependencies should have been installed at the same time as the main application. It's a ubuntu/debian packaging problem.

2) With so many linux distros, one never knows how the application will be packaged and who will encounter the same problem as I did in the future. The warning box in the application should be more helpful, at least by providing a direct link to the application's official documentation, and listing all the dependencies for each known distribution (apt-based, rpm-based, etc.)