I wonder how much storage I’m going to save converting my mp3 library to opus
Depend on the source and output quality you have. Also do not forget conversion from lossy into lossy format will degrade quality too, even if its most of the time not noticeable. If you have them all in constant 320 kbit/s, then you could probably get a good chunk of space without sacrificing quality much.
As for the software recommendation, it would be good to know what operating system you are on. Windows, Android, iOS, Linux PC?
Depend on the source and output quality you have. Also do not forget conversion from lossy into lossy format will degrade quality too, even if its most of the time not noticeable. If you have them all in constant 320 kbit/s, then you could probably get a good chunk of space without sacrificing quality much.
As for the software recommendation, it would be good to know what operating system you are on. Windows, Android, iOS, Linux PC?
Oops, I forgot to mention the OS, it’s Win11 (I edited the main post now).