Automated download scripts (like those on GitHub) use these tags to sort episode intros or "Openings." 💡

It features the Straw Hat crew's backstories (Nami, Usopp, Sanji, Zoro, Luffy).

Used by fans to share high-quality video files of the intro.

is most likely a specific file naming convention or a reference to a specific piece of media, such as a One Piece (OP) opening theme or a promotional clip, rather than a widely recognized industry standard or software.

Refers to the version number, sequence number, or fourth iteration.

The final delivery format using H.264 or H.265 compression. 💻 Programming or Scripts If you encountered this in a codebase:

Because "Op04mp4" isn't a standard technical term, it usually refers to one of the following: 📺 Anime Media (One Piece)