Archive at home, MP3 on the road
A FLAC library is the right way to keep music: bit-perfect, future-proof. It is also the wrong thing to hand a car stereo, a USB stick for an old player or a phone with a full disk. This tool encodes at 320 kbps โ the ceiling of the MP3 format โ so the travelling copy gives up as little as possible.
Drop an album, get an album back. Everything is converted by your own device; a music collection has no business passing through anyone's server.
One-way street, said plainly
MP3 discards detail to get small, and that detail never returns โ converting the MP3 back to FLAC later would only preserve the loss in a bigger box. Keep the FLACs as your master archive; the MP3s are disposable copies you can regenerate any time.
Frequently asked questions
Why 320 kbps and not a choice?
Coming from lossless, it makes sense to spend the few extra megabytes: 320 kbps is the best MP3 can do, and for nearly all ears and gear it's indistinguishable from the source.
Will I hear the difference from FLAC?
On car speakers and earbuds โ no. In a quiet room on serious equipment, a trained ear might. That's exactly why the FLAC stays as the archive.
Can I convert MP3 back to FLAC to restore quality?
No โ lost detail is gone for good. A FLAC made from an MP3 is just a large, faithful copy of the MP3.