You are saving your music in a format more efficient than opus or aac? What format is that?
Chiptune formats for retro videogame music can be very efficient. Just picking two with particularly good music, I have a 21 KB (0.02 MB) file storing 28:30 of music and 4.72 MB of files storing 1:54:48 of music, both at source quality.
The catch is that they are designed exclusively to rip chiptunes from retro videogames as close as the format designers and player coders could manage to the original. So even the oversized ones like the 4.72 MB of files extracted from a 3 MB game are going to be far smaller than a general use format like opus. But you can’t encode your own music in the format without going to massive effort to code it like you would an authentic chiptune, and you’re unlikely to like the results.
Can you name the format you’re using to store 1:54:48 of music in 4.72 MB?
Those are SPC files, and that particular example was one rip of Final Fantasy VI (III)'s soundtrack.
Unfortunately, it only handles music embedded in Super Famicom/Super Nintendo games. To convert your own music to SPC, you’d have to rewrite it for the SNES sound chip.
Damn, may I ask how big your entire library is? At those sizes, you can store more music than I’ll ever need in a couple of gbs.
Everything filed under “Chiptune”, excluding the AT3 and MAB files which are effectively general purpose music formats, comes to 1.14 GB for 4211 items totaling 158:50:29. There are a lot of duplicates in there, because for a lot of these items it’s more trouble to hunt down a replacement copy than it is to store a backup.
The catch, of course, is that it’s all retro videogame music from bleep to bloop.