Hey Hi-FiMan,
Thanks for the kind reply! In regards to using Japanese information, this is something that could be considered. Right now, only English is scraped because the lion-share of users online use English as their primary or secondary language. This is also important for metadata, since linking actors, genres, and series would not work across different languages. For example, it is impossible for software to know that “Momo Sakura” is really “桜空もも” in Japanese, so the relationship between them is lost.
In regards to identifiers, Indeed the program does not use the DVD ID when tagging videos. While DVD IDs may appear to be unique, there are many edge-cases where one DVD ID will collide with another ID from a different studio. That’s why the Content ID is used as an identifier instead, since it is guaranteed to be unique across all entries. I suppose a flag could be added to use DVD IDs instead for naming, but to be honest, your the first person to request this as that information can be found in the meta-data anyway. (^_^); You could as a workaround use the “--alt-naming-method” and set the flag to “dvd-id” and see if that works better for you. Though, I suspect that may not be exactly what you want.
Anyway, these feature requests are probably feasible (DVD ID more-so than Japanese scraping, due to technical limitations), but as always, I need to prioritize my backlog work based on what will benefit the most people. Naturally, Patreon requests get prioritized higher in the backlog as well.