I’m new to Beets and i’m unable to find this information anywhere.
How can i format the “track number” field directly sotred inside the MP3 tags by padding the value with 0 as a prefix (depending on the size of the current track number : 1 will be padded as “01” and “12” will of couse be kept as is).
That’s not currently possible; sorry! Our tag abstraction layer exposes these values as integers, not strings, so beets doesn’t give you control over that kind of detail.
mediafile still exposes track as an integer, so this isn’t supported at the moment. It’s a bit of a hack but you could possibly look at using the hook plugin with the after_write event to modify the file’s metadata yourself once beets is done with it.