Fix .webm files not including the `FFmpeg:VideoBitRate` and `FFmpeg:AudioBitRate`
fields in the media_metadata table. This was because the .webm format
doesn't include the video or audio bit rates in the metadata, and
ffprobe doesn't calculate them either, so we have to calculate them
ourselves by hand.
Fixup for 523d7afdd.
This directory contains library code used through Danbooru. This includes things like defining API clients, dealing with
sources, parsing tag searches, storing and resizing images, and so on.
Many of the files here use the Service Object pattern. Instead of putting complex code in models or controllers, it goes
here, in plain old Ruby objects (POROs). This keeps models and controllers simpler, and keeps domain logic isolated and
independent from the database and the HTTP request cycle.